enemy.py

"""
enemy.py:
Define all kinds of monsters and impediments in game.
Classes in this module is organised in the order of chapters.
"""
import pygame
from pygame.image import load
from pygame.transform import flip   # this function is non-destructive to images
from pygame.sprite import collide_mask
import math
from random import choice, random, randint

from database import MB, NB, DMG_FREQ
from util import InanimSprite, HPBar
from util import getPos, rot_center, generateShadow, getCld


# -------------------------------------------------
# some helpful functions for this module
def cldList(subject, objList):
    '''Check whether subject collides with any object in the list:
    if yes, invoke hitted() of the collided object.'''
    for each in objList:
        if ( collide_mask( subject, each ) ):
            each.hitted( subject.damage, subject.push, subject.dmgType )
            if hasattr(subject, "dmgType") and subject.dmgType=="freezing":
                each.freeze(1)
            return each   # 返回碰撞对象表示发生碰撞，否则函数最后返回默认值None

def createCanvas(size, colorKey=(0,0,0)):
    '''为调用者生成一个画布对象。接受参数为画布尺寸和透明色信息（RGB无A），返回画布的surface及其rect。'''
    canvas = pygame.Surface( size ).convert()
    canvas.set_colorkey( colorKey )  # set black as transparent color, generally make the canvas transparent
    cRect = canvas.get_rect()
    cRect.left = 0
    cRect.top = 0
    return (canvas, cRect)

def createImgList(*paths):
    '''为调用者生成一个含左右图片列表的字典并返回。接受参数为左向的图片路径列表。注意使用了收集参数的机制，
    必须要把所有图片路径按顺序传入。如果实际只有一个图片传入，字典中的元素也会是列表，该表中只有一张图。'''
    imgDic = { "left":[], "right":[] }
    # 先建立left图片列表，再依次变换至right图片列表
    for path in paths:
        imgDic["left"].append( load(path).convert_alpha() )
    for img in imgDic["left"]:
        imgDic["right"].append( flip(img, True, False) )
    return imgDic

def getShadLib(imgLib):
    '''根据所给的imgLib转化出相应的阴影shadLib，并返回（适用于monsters）'''
    shadLib = {}
    for name in imgLib:            # 对于每一项动作名称
        shadLib[name] = { "left":[], "right":[] }
        for dir in imgLib[name]:   # 对于该动作的每一方向
            for img in imgLib[name][dir]:
                shadLib[name][dir].append( generateShadow(img) )
    return shadLib


# ========================================================================
# Basic class for all monsters: 
# 此类将提供所有enemy应有的方法和属性，子类可在此基础上扩展
# ========================================================================
class Monster(InanimSprite):

    # NOTE: 所有的怪物类别都应维护自己的一些媒体静态变量。它们应该只加载一次，然后所有实例都可以使用这些媒体对象，如图片、声音。
    # 以下是monster大类共享的2个共享静态变量。在模式初始化时，由model对象来对这2个值进行初始化。（1表示原生命）
    healthBonus = 1
    # model的spurtcanvas对象，每个monster均应能快速访问，来实现多种效果
    spurtCanvas = None
    # monster 眩晕图片列表
    stun_img = []
    # a msgList of the model: could be visited by all monsters
    msgList = None

    def __init__(self, cate, bldColor, push, weight, onlayer, 
                    sideGroup=None, shadOffset=8, bar=False, debri=()):
        '''debri: pair (debriType, num)'''
        InanimSprite.__init__(self, cate)   # 首先它应该是一个InanimSprite
        if not Monster.stun_img:
            Monster.stun_img = [load("image/stun_1.png"), load("image/stun_2.png"), 
                    load("image/stun_3.png"), load("image/stun_4.png")]
            Monster.stun_rect = Monster.stun_img[0].get_rect()
        self.bldColor = bldColor            # tuple类型
        self.health = round( MB[cate].health * self.healthBonus )
        self.full = self.health
        self.coin = MB[cate].coin
        self.damage = MB[cate].damage
        self.dmgType = MB[cate].dmgType     # 伤害类型：大部分为物理伤害。
        self.manner = MB[cate].manner       # 行为方式：大部分为地面类型。
        self.armor = MB[cate].armor         # 护甲(伤害减免)：大部分无减伤。

        self.pushList = (-push, push)
        self.push = push
        self.weight = weight
        self.hitBack = 0
        self.realDmgRate = 1-self.armor
        self.shadOffset = shadOffset
        
        self.onlayer = int(onlayer)         # 怪物的onlayer是其所处的砖块的层数。
        self.direction = "left"             # 默认初始朝left。若需自定义，可在monster子类的构造函数中修改本值。
        self.gravity = 0
        self.obstacle = pygame.sprite.Group()
        if sideGroup:
            self.renewObstacle(sideGroup)

        # The followings are parameters about HP bar.
        self.bar = HPBar(self.full, blockVol=200, barH=10) if bar else None
        self.debri = debri
        self.stun_time = 0

    def alterSpeed(self, speed):
        self.speed = speed
        if speed > 0:
            self.direction = "right"
        elif speed < 0:
            self.direction = "left"
        self.push = self.pushList[0] if (self.direction=="left") else self.pushList[1]

    def checkHitBack(self, obstacle=False):
        if abs(self.hitBack)>0:
            # NOTE:和fall的处理方式不同。如果和参数中的物体相撞，则尝试保持原位置不变并直接消除hitback效果，而不是移至物体之外。
            if pygame.sprite.spritecollide(self, self.obstacle, False, collide_mask):
                self.hitBack = 0
                return False
            self.rect.left += self.hitBack
            self.hitBack -= self.hitBack//abs(self.hitBack) # 大于0取1，小于零取-1。
            return True
        return False
    
    def fall(self, keyLine, groupList, GRAVITY):
        if self.gravity<GRAVITY:
            self.gravity += 1
        self.rect.bottom += self.gravity
        while ( pygame.sprite.spritecollide(self, self.wallList, False, collide_mask) ):  # 如果和参数中的物体相撞，则尝试纵坐标-1
            self.rect.bottom -= 1
            self.gravity = 0
        if self.rect.top >= keyLine:
            self.onlayer  = max(self.onlayer-2, -1)
            self.initLayer( groupList[str(self.onlayer)], groupList["0"], wallChosen=True )
            # 更新obstacle砖块
            self.renewObstacle(groupList["0"])
    
    def initLayer(self, lineGroup, sideGroup, wallChosen=False):
        '''
        用于确定新一行中的位置及scope。
        param lineGroup: 该行的所有lineWall。
        param sideGroup: Add sidewalls that are of same layer to avoid monsters fall from the top layer.
        '''
        self.wallList = []          # 存储本行的所有砖块。每次初始化一个新实例时，清空此类的wallList
        posList = []                # 辅助列表，用于暂时存储本行砖块的位置（左边线）
        # 若已确定位置，是在下落过程中重新更新layer。
        if wallChosen:
            wall = None          # 此刻monster正下方的wall
            for aWall in lineGroup:   # 由于spriteGroup不好进行索引/随机选择操作，因此将其中的sprite逐个存入列表中存储
                if aWall.category in ("lineWall","specialWall","baseWall"):
                    self.wallList.append(aWall)
                    posList.append(aWall.rect.left)
                    if aWall.rect.left<getPos(self,0.5,0)[0]<aWall.rect.right:  # 可以落到下一行上，有砖接着
                        wall = aWall
            if not wall:         # 没wall接着，直接返回，继续下落吧！
                return None
        # 否则，是首次生成，直接随机选择生成地。
        else:
            for aWall in lineGroup:  # 由于spriteGroup不好进行索引/随机选择操作，因此将其中的sprite逐个存入列表中存储
                self.wallList.append(aWall)
                posList.append(aWall.rect.left)
            wall = choice(self.wallList)
        # 到了这一步，已经得到了wall，好，可以开始计算scope了。
        leftMax = wall.rect.left
        rightMax = wall.rect.right          # note：此处砖块的右坐标即下一砖块的左坐标
        while True:
            if leftMax in posList:          # warmachine比较宽，可以占两格行进
                leftMax -= wall.rect.width
            else:
                leftMax += wall.rect.width  # 将多减的加回来
                break
        while True:
            if rightMax in posList:
                rightMax += wall.rect.width
            else:
                break
        self.scope = (leftMax, rightMax)
        # Add sidewalls of the same layer to wallList
        for each in sideGroup:
            if each.coord[1]==self.onlayer:
                self.wallList.append(each)
        return wall
    
    def renewObstacle(self, sideGroup):
        # 更新obstacle砖块
        self.obstacle.empty()
        for each in sideGroup:
            if each.coord[1] == self.onlayer+1:
                self.obstacle.add(each)

    def detectHero(self, heroes):
        for hero in heroes:
            # 如果有英雄在同一层，则将速度改为朝英雄方向。
            if (hero.onlayer-1)==self.onlayer and ( self.scope[0]<=getPos(hero,0.5,0)[0]<=self.scope[1] ):
                if self.speed*( getPos(hero,0.5,0)[0]-getPos(self,0.5,0)[0] ) < 0:
                    self.alterSpeed(-self.speed)
                return hero
        return None

    def paint(self, surface):
        '''所有monster都应有paint()函数，供外界调用，将自身画在传来的surface上。NOTE:此函数不负责绘制生命条，应该由怪物管理类主动绘制'''
        # 画阴影
        shadRect = self.rect.copy()
        shadRect.left -= self.shadOffset
        surface.blit(self.shad, shadRect)
        surface.blit( self.image, self.rect )
        # 画打击阴影
        if self.hitBack:
            surface.blit( self.shad, self.rect )
        
    # stun(): similar to hero's freeze()
    def stun(self, duration):
        self.stun_time = duration
        self.reset()

    def reset(self):    # to be override by specific monster class
        pass

    def count_stun(self):
        if self.stun_time>0:
            self.stun_time -= 1
    
    def setImg(self, name, indx=0):  # 根据状态名称切换图片。如果是列表，应给出indx值。
        self.image = self.imgLib[name][self.direction][indx]
        self.shad = self.shadLib[name][self.direction][indx]
    
    def drawHealth(self, surface):
        if self.bar:
            self.bar.paint(self, surface)
        # 画眩晕
        if self.stun_time > 0:
            self.stun_rect.bottom = self.rect.top
            self.stun_rect.left = self.rect.left +self.rect.width//2 -self.stun_rect.width//2
            surface.blit(self.stun_img[self.stun_time//3%4], self.stun_rect)
        
    def assignGoalie(self, HPInc):
        # Redefine its health. All settings will be inherited.
        self.full = self.health = round( self.health * HPInc )
        if self.bar:
            self.bar = HPBar(self.full, blockVol=self.bar.blockVol, barH=self.bar.barH, color="goldRed", icon=True)

    def hitted(self, damage, pushed, dmgType):
        # decrease health
        true_dmg = round(damage*self.realDmgRate)
        self.health -= true_dmg
        self.msgList.append( [getPos(self,0.5,0.5), str(true_dmg), 60] )
        if self.health <= 0:        # dead
            self.health = 0
            if self.debri:
                self.spurtCanvas.addPebbles(self, self.debri[1], type=self.debri[0])
            self.kill()
            return True
        if pushed>0:   # 向右击退
            self.hitBack = max( pushed-self.weight, 0 )
        elif pushed<0: # 向左击退
            self.hitBack = min( pushed+self.weight, 0 )

    def recover(self, heal):
        if self.health<=0:
            return
        #self.spurtCanvas.addSpatters(8, (2,3,4), (20,22,24), (10,240,10), getPos(self,0.5,0.4) )
        self.health += heal
        self.msgList.append( [getPos(self,0.5,0.5), "+"+str(heal), 60, "green"] )
        if (self.health > self.full):
            self.health = self.full

# Boss: 比普通Monster更高级一些，拥有更多属性和特殊方法
class Boss(Monster):
    '''Boss相比于Monster，拥有一些特殊的行为和属性'''
    def __init__(self, font, cate, bldColor, push, weight, onlayer, sideGroup=None, shadOffset=8, bar=True):
        Monster.__init__(self, cate, bldColor, push, weight, onlayer, sideGroup, shadOffset)
        self.activated = False
        self.font = font    # For showing outscreen pos
        self.bar = HPBar(self.full, blockVol=200, barH=12)

    def _tipPosition(self, canvas):
        if (self.rect.top > canvas.rect.height):
            txt = self.font.render( "▼ "+str(self.rect.top-canvas.rect.height), True, (255,255,255) )
            canvas.txtList.append( [txt, "BOTTOM"] )
        elif (self.rect.bottom < 0):
            txt = self.font.render( "▲ "+str(-self.rect.bottom), True, (255,255,255) )
            canvas.txtList.append( [txt, "TOP"] )

    def initLayer(self, groupList):
        """Boss 一般体型较大，有其特殊的处理行砖方式"""
        self.wallList = []
        posList = []                # 辅助列表，用于暂时存储本行砖块的位置（左边线）
        while True:    # in case that wallList of chosen layer is empty
            for aWall in groupList[str(self.onlayer)]:  # 由于spriteGroup不好进行索引/随机选择操作，因此将其中的sprite逐个存入列表中存储
                self.wallList.append(aWall)
                posList.append(aWall.rect.left)
            if not self.wallList:
                self.onlayer -= 2
            else:
                break
        wall = choice(self.wallList)
        self.initPos = getPos(wall, 0.5, 0)   # 新点，居中
        leftMax = wall.rect.left
        rightMax = wall.rect.right
        while True:
            if (leftMax in posList) or (leftMax-wall.rect.width in posList): # Chicheng比较宽，可以占两格行进
                leftMax -= wall.rect.width
            else:
                leftMax += wall.rect.width
                break
        while True:
            if (rightMax in posList) or (rightMax+wall.rect.width in posList):
                rightMax += wall.rect.width
            else:
                break 
        self.scope = (leftMax-wall.rect.width//2, rightMax+wall.rect.width//2)
        # Add sidewalls of the same layer to wallList
        for each in groupList["0"]:
            if each.coord[1]==self.onlayer:
                self.wallList.append(each)
        return wall

# Ajunction: 一个Boss往往由一个Boss主体和多个Ajunction构成，如Dragon=身体本身(Boss类)+翅膀+头+尾巴（后三个均为Ajunction）
class Ajunction(pygame.sprite.Sprite):
    '''此类应附属于某个monster主体而存在。由于是附属物，此类只提供供主物移动位置、替换image的函数接口，需要主物来执行相应的删除工作。'''
    def __init__(self, img, pos):
        pygame.sprite.Sprite.__init__(self)
        self.image = img
        self.rect = self.image.get_rect()
        self.rect.left = pos[0] - self.rect.width//2
        self.rect.bottom = pos[1] - self.rect.height//2
        self.mask = pygame.mask.from_surface(self.image)

    def updatePos(self, pos):
        self.rect.left = pos[0] - self.rect.width//2
        self.rect.top = pos[1] - self.rect.height//2
    
    def updateImg(self, img):
        trPos = [ self.rect.left + self.rect.width//2, self.rect.top + self.rect.height//2 ]
        self.image = img
        self.rect = self.image.get_rect()
        self.rect.left = trPos[0]-self.rect.width//2
        self.rect.bottom = trPos[1]
        self.mask = pygame.mask.from_surface(self.image)


# ========================================================================
# ------------------------- CP 0 (endless mode)---------------------------
# ========================================================================
class BiteChest(Monster): 
    imgLib = None
    shadLib = None

    def __init__(self, wallGroup, sideGroup, onlayer):
        if not self.imgLib:
            BiteChest.imgLib = {
                "iList": createImgList("image/stg0/biteChest1.png","image/stg0/biteChest0.png","image/stg0/biteChest0.png",
                    "image/stg0/biteChest0.png","image/stg0/biteChest0.png","image/stg0/biteChest0.png", 
                    "image/stg0/biteChest1.png")
            }
            BiteChest.shadLib = getShadLib(BiteChest.imgLib)
        # calculate its position
        Monster.__init__(self, "biteChest", (250,210,160), 4, 3, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        self.coin = randint(6,10)

        # initialize the sprite
        self.imgIndx = 0
        self.setImg("iList",0)
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top
        self.reset()
        self.restCnt = self.resetCntFull = 8
        self.alterSpeed( choice([-1,1]) )
        self.rise = ( 1, -8, -13, -16, -13, -8, 1 )

    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        
        if self.imgIndx<len(self.rise)-1:       # 在空中时水平移动
            if self.stun_time==0:
                self.rect.left += self.speed
            if (getPos(self,0.8,0)[0]>=self.scope[1] and self.speed>0) or (getPos(self,0.2,0)[0]<=self.scope[0] and self.speed<0):
                self.alterSpeed( -self.speed )
            if not (delay % 4 ):
                trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom-self.rise[self.imgIndx] ]  # 为保证图片位置正确，临时存储之前的位置信息
                self.imgIndx += 1
                self.setImg("iList",self.imgIndx)
                self.mask = pygame.mask.from_surface(self.image)
                self.rect = self.image.get_rect()
                self.rect.left = trPos[0]-self.rect.width//2
                self.rect.bottom = trPos[1] + self.rise[self.imgIndx]
        else:
            if self.stun_time==0:
                # rise最后一下落地，0.33秒停顿
                self.restCnt -= 1
                if self.restCnt<0:
                    self.restCnt = self.resetCntFull
                    self.imgIndx = 0
        if self.stun_time==0:
            # Bite
            if ( self.coolDown==0 ):
                for each in sprites:
                    if collide_mask(self, each):
                        self.coolDown = 36
            elif (self.coolDown > 0):
                self.coolDown -= 1
                if ( self.coolDown == 20 ):
                    cldList( self, sprites )

    def reset(self):
        self.coolDown = 0

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)


# ========================================================================
# --------------------------------- CP 1 ---------------------------------
# ========================================================================
class InfernoFire(InanimSprite):
    def __init__(self, bg_size):
        InanimSprite.__init__(self, "infernoFire")
        self.ori_imgList = [load("image/stg1/infernoFire0.png").convert_alpha(), 
            load("image/stg1/infernoFire1.png").convert_alpha(), 
            load("image/stg1/infernoFire2.png").convert_alpha()]
        self.snd = pygame.mixer.Sound("audio/infernoFire.wav")
        self.width = bg_size[0]
        self.height = bg_size[1]
        self.damage = NB["infernoFire"]["damage"]
        self.dmgType = "fire"
        self._reset()

    def update(self, delay, sprites, canvas):
        if self.rect.top<self.height:
            self.rect.left += self.speed[0]
            self.rect.top += self.speed[1]
            color = choice( [(60,10,0,210), (120,40,0,210)] )
            canvas.addTrails( [3,5,7], [21,24,27], color, getPos(self, 0.3+random()*0.4, 0.5+random()*0.1) )
        else:
            self._reset()
            return
        if not delay%DMG_FREQ:
            for each in sprites:
                if ( collide_mask( self, each ) ):
                    if each.rect.left+each.rect.width//2 > self.rect.left+self.rect.width//2:
                        each.hitted(self.damage, 3, self.dmgType)
                        canvas.addSpatters( 4, (2,4,6), (6,7,8), (255,240,0,230), getPos(self, 0.5+random()*0.5, 0.2+random()*0.2), True )
                    else:
                        each.hitted(self.damage, -3, self.dmgType)
                        canvas.addSpatters( 4, (2,4,6), (6,7,8), (255,240,0,230), getPos(self, random()*0.5, 0.2+random()*0.2), False )
        if not (delay % 5):              # 切换图片
            self.imgIndx = ( self.imgIndx+1 ) % len(self.imgList)
            self.image = self.imgList[self.imgIndx]
            self.mask = pygame.mask.from_surface(self.image)
    
    def _reset(self):
        self.snd.play(0)
        self.speed = [choice([-5, 5]), 3]
        rot = -115 if self.speed[0]<0 else 115
        self.imgList = [pygame.transform.rotate(each, -rot) for each in self.ori_imgList]
        self.image = self.imgList[0]
        self.imgIndx = 0
        self.rect = self.image.get_rect()
        self.mask = pygame.mask.from_surface(self.image)
        if self.speed[0]<0:
            self.rect.left = self.width
        else:
            self.rect.right = 0
        self.rect.bottom = randint(-60, self.height//2)

# -----------------------------------
class Tizilla(Monster):
    imgLib = None
    shadLib = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLib:
            Tizilla.imgLib = {
                "iList": createImgList( "image/stg1/tizilla0.png", "image/stg1/tizilla1.png", 
                    "image/stg1/tizilla0.png", "image/stg1/tizilla2.png" ),
                "attList": createImgList( "image/stg1/tizillaAtt1.png", 
                    "image/stg1/tizillaAtt2.png", 
                    "image/stg1/tizillaAtt3.png", 
                    "image/stg1/tizillaAtt4.png")
            }
            Tizilla.shadLib = getShadLib(Tizilla.imgLib)
        
        # calculate its position
        Monster.__init__(self, "tizilla", (255,0,0,240), 6, 1, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top
        self.alterSpeed( choice([1,-1]) )

    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()

        self.rect.bottom += self.gravity

        if self.stun_time==0:
            self.rect.left += self.speed
            if (getPos(self,0.8,0)[0] >= self.scope[1] and self.speed > 0) or (getPos(self,0.2,0)[0] <= self.scope[0] and self.speed < 0):
                self.alterSpeed(-self.speed)
            if not (delay % 8):
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                self.setImg("iList",self.imgIndx)
            if ( self.coolDown==0 ):
                for each in sprites:
                    if collide_mask(self, each):
                        self.coolDown = 40
            if (self.coolDown > 0):
                self.coolDown -= 1
                self.cratch( sprites )
            # Check Hero and Turn speed
            self.detectHero(sprites)
    
    def cratch(self, sprites):
        if (self.coolDown <= 22):
            return
        if (self.coolDown >= 36):
            self.attIndx = 0
        elif (self.coolDown >= 32):
            self.attIndx = 1
        elif (self.coolDown >= 29):
            self.attIndx = 2
        elif (self.coolDown >= 26):
            self.attIndx = 3
            if ( self.coolDown == 26 ):
                cldList( self, sprites )
        trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]
        self.setImg("attList",self.attIndx)
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = trPos[0]-self.rect.width//2
        self.rect.bottom = trPos[1]

    def reset(self):
        self.imgIndx = 0
        self.attIndx = 0
        self.setImg("iList",0)
        self.coolDown = 0

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

# -----------------------------------
class MegaTizilla(Monster):
    imgLib = None
    shadLib = None
    fireSnd = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLib:
            MegaTizilla.imgLib = {
                "iList": createImgList( "image/stg1/megaTizilla0.png", "image/stg1/megaTizilla1.png", 
                    "image/stg1/megaTizilla0.png", "image/stg1/megaTizilla2.png" ),
                "att": createImgList( "image/stg1/megaTizillaAtt.png"), 
                "alarm": createImgList("image/stg1/megaTizillaAlarm.png")
            }
            MegaTizilla.shadLib = getShadLib(MegaTizilla.imgLib)
            MegaTizilla.fireSnd = pygame.mixer.Sound("audio/megaTizFire.wav")
        
        # calculate its position
        Monster.__init__(self, "megaTizilla", (255,0,0,240), 6, 3, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top
        self.alterSpeed( choice([1,-1]) )
        self.hitAccum = 0
    
    def move(self, delay, sprites, canvas):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        if self.stun_time==0:
            if (self.airCnt==0):
                if not (delay%2):
                    self.rect.left += self.speed
                    self.rect.bottom += self.gravity
                    # touch the edge and turn around
                    if (getPos(self,0.75,0)[0] >= self.scope[1] and self.speed > 0) or (getPos(self,0.25,0)[0] <= self.scope[0] and self.speed < 0):
                        self.alterSpeed(-self.speed)
                    # renew image
                    if not (delay % 10):
                        trPos = [ self.rect.left+self.rect.width//2, self.rect.bottom ]
                        self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                        self.setImg("iList",self.imgIndx)
                        self.rect = self.image.get_rect()
                        self.rect.left = trPos[0]-self.rect.width//2
                        self.rect.bottom = trPos[1]
                for hero in sprites:
                    heroPos = getPos(hero,0.5,0)
                    myPos = getPos(self,0.5,0)
                    # 如果有英雄在同一层，则将速度改为朝英雄方向。
                    if (hero.onlayer-1)==self.onlayer:
                        # 判断是否需要转向
                        if ( self.scope[0]<=heroPos[0]<=self.scope[1] ):
                            if self.speed*( heroPos[0]-myPos[0] ) < 0:
                                self.alterSpeed(-self.speed)
                                break     # ***这里碰到第一个英雄符合条件就退出了。因此，如果两个英雄同时在一层中，P1总是会被针对，而P2永远不会被选中为目标。
                        # 判断是否需要攻击
                        if (self.speed<0 and -225<=heroPos[0]-myPos[0]<0) or (self.speed>0 and 0<heroPos[0]-myPos[0]<225):
                            self.airCnt = 76
                            self.fireSnd.play(0)
            elif self.airCnt>0:
                self.airCnt -= 1
                if self.airCnt>60:
                    self.setImg("alarm")
                else:
                    self.setImg("att")
                    if self.speed <= 0:
                        spd = [ choice([-3,-4]), choice([-2, -1, 1, 2]) ]
                        startX = 0.34
                    elif self.speed > 0:
                        spd = [ choice([3,4]), choice([-2, -1, 1, 2]) ]
                        startX = 0.66
                    # 每次刷新均吐出2个气团
                    canvas.addAirAtoms( self, 2, getPos(self, startX, 0.37), spd, sprites, "fire" )
    
    def reportHit(self, tgt):
        self.hitAccum += 1
        if self.hitAccum>=12:
            self.hitAccum = 0
            tgt.hitted( self.damage, self.push, "fire" )

    def reset(self):
        self.imgIndx = 0
        self.attIndx = 0
        self.setImg("iList",0)
        self.airCnt = 0           # indicate if spitting!

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)
    
# -----------------------------------
class Dragon(Monster):
    imgLib = None
    shadLib = None
    fireSnd = None

    def __init__(self, wallHeight, onlayer, boundaries):
        if not self.imgLib:
            Dragon.imgLib = {
                "iList": createImgList("image/stg1/dragonLeft0.png","image/stg1/dragonLeft1.png",
                    "image/stg1/dragonLeft2.png","image/stg1/dragonLeft3.png",
                    "image/stg1/dragonLeft2.png","image/stg1/dragonLeft1.png")
            }
            Dragon.shadLib = getShadLib(Dragon.imgLib)
            Dragon.fireSnd = pygame.mixer.Sound("audio/dragonFire.wav")
        
        # calculate its position
        Monster.__init__(self, "dragon", (255,0,0,240), 0, 1, onlayer)
        self.boundaries = boundaries
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = randint(boundaries[0], boundaries[1]-self.rect.width)
        self.rect.top = wallHeight - 190
        self.alterSpeed( choice([-1, 1]) )

    def move(self, delay):
        self.checkHitBack()
        self.count_stun()

        if not (delay % 20):
            self.rect.top += self.upDown
            self.upDown = - self.upDown
        if not (delay % 6 ):
            self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
            self.setImg("iList",self.imgIndx)
        if self.stun_time==0:
            self.rect.left += self.speed
            if (self.rect.left<=self.boundaries[0] and self.speed < 0) or (self.rect.right>=self.boundaries[1] and self.speed > 0):
                self.alterSpeed(-self.speed)
            # randomly fire
            self.coolDown -= 1
            if self.coolDown<=0:
                self.fireSnd.play(0)
                self.coolDown = randint(120,480)
                return Fire(getPos(self, 0, 1), self.onlayer, -2, 0) if (self.direction=="left") else Fire(getPos(self,0.95,1), self.onlayer, 2, 0)
        return None

    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.coolDown = randint(240,480)
        self.upDown = 2

    def level(self, dist):
        self.rect.left += dist
        self.boundaries = (self.boundaries[0]+dist, self.boundaries[1]+dist)
    
class Fire(InanimSprite):
    def __init__(self, pos, layer, speed, iniG):
        InanimSprite.__init__(self, "fire")
        self.ori_image = load("image/stg1/fire.png").convert_alpha()
        self.image = self.ori_image.copy()
        self.rect = self.image.get_rect()
        self.rect.left = pos[0]
        self.rect.bottom = pos[1]
        self.mask = pygame.mask.from_surface(self.image)
        self.damage = MB["dragon"].damage
        self.dmgType = MB["dragon"].dmgType
        self.onlayer = int(layer)
        self.gravity = iniG
        self.speed = speed
        self.angle = 0
        if speed>0:
            self.push = 6
        else:
            self.push = -6

    def update(self, delay, sideWalls, downWalls, keyLine, sprites, canvas, bg_size):
        self.rect.left += self.speed
        self.rect.bottom += self.gravity
        canvas.addTrails( [4,5,6], [8,10,12], (240,190,0,220), getPos(self, 0.4+random()*0.3, 0.4+random()*0.3) )
        if cldList( self, sprites ):      # 命中英雄
            self._explode(canvas)
            return None
        if ( pygame.sprite.spritecollide(self, downWalls, False, collide_mask) ) or ( pygame.sprite.spritecollide(self, sideWalls, False, collide_mask) ) or self.rect.top>=bg_size[1] or self.rect.right<=0 or self.rect.left>=bg_size[0]:
            self._explode(canvas)
            return None
        if not (delay % 6):
            if self.speed <= 0:
                self.angle = (self.angle+40) % 360
            else:
                self.angle = (self.angle-40) % 360
            self.image = rot_center(self.ori_image, self.angle)
            if (self.gravity < 5):
                self.gravity += 1
        if ( self.rect.top >= keyLine ):  # 因为只有大于检查，因此只有初始行之下的砖块会与之碰撞
            self.onlayer = max(self.onlayer-2, -1)
        return None

    def _explode(self, canvas):
        canvas.addSpatters( 5, [4,5,6], [18,20,22], (20,10,10,255), getPos(self,0.5,0.8), True )
        canvas.addSmoke(5, (6,8,10), 6, (10,10,10,180), getPos(self,0.5,0.8), 10)
        self.kill()
        del self

#------------------------------------
class DragonEgg(Monster):
    imgLib = None
    shadLib = None
    fireSnd = None
    crushSnd = None

    def __init__(self, wallGroup, sideGroup, onlayer):
        if not self.imgLib:
            DragonEgg.imgLib = {
                "iList": createImgList("image/stg1/dragonEgg.png", "image/stg1/dragonEggBroken.png"),
                "baby": createImgList("image/stg1/eggBaby.png", "image/stg1/eggBabyAtt.png")
            }
            DragonEgg.shadLib = getShadLib(DragonEgg.imgLib)
            DragonEgg.fireSnd = pygame.mixer.Sound("audio/dragonFire.wav")
            DragonEgg.crushSnd = pygame.mixer.Sound("audio/wizard/hit.wav")
        
        # calculate its position
        Monster.__init__(self, "dragonEgg", (250,0,80,240), 0, 4, onlayer, sideGroup)
        # note： 这里bowler的onlayer，以及其stone的onlayer值均为砖的行数，并非自身的行数，使用时不需要-1操作
        self.wallList = []       # 存储本行的所有砖块;
        for aWall in wallGroup:  # 由于spriteGroup不好进行索引/随机选择操作，因此将其中的sprite逐个存入列表中存储
            self.wallList.append(aWall)
        wall = choice(self.wallList)
        # initialize the sprite
        self.imgIndx = 0
        self.setImg("iList",0)
        self.attCnt = 0
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top
        # Inner baby dragon
        self.babyR = { "left":[ (0.5,0.04), (0.52,0.06) ], "right":[ (0.5,0.04), (0.48,0.06) ] }    # 分别为左和右时的位置信息
        self.baby = Ajunction( 
                            self.imgLib["baby"][self.direction][0], 
                            getPos(self, self.babyR[self.direction][0][0], 
                            self.babyR[self.direction][0][1]) 
                    )
        self.barOffset = 30

    def move(self, delay, sprites):
        if self.health<=0:
            return
        # checkhitback: 仅计算时间，不进行位移
        if abs(self.hitBack)>0:
            self.hitBack -= self.hitBack//abs(self.hitBack)
                
        # update baby image. Note: 因为有壳保护，龙宝不会受到stun效果影响。
        if self.attCnt>0:
            self.attCnt -= 1
            r = self.babyR[self.direction][1]
            bimg = self.imgLib["baby"][self.direction][1]
        else:
            r = self.babyR[self.direction][0]
            bimg = self.imgLib["baby"][self.direction][0]
        self.baby.updateImg( bimg )
        self.baby.updatePos( getPos(self, r[0], r[1]) )

        if not (delay % 30 ):
            heroX = choice(sprites).rect.left
            if self.rect.left > heroX:
                self.direction = "left"
            else:
                self.direction = "right"
            # randomly fire
            if not (delay % 60) and random()<0.4:  # Controlling the frequency of fire.
                self.attCnt = 12
                self.fireSnd.play(0)
                if self.direction=="left":
                    return Fire(getPos(self,0.2,0), self.onlayer+2, randint(-3,-1), -2)
                else:
                    return Fire(getPos(self,0.8,0), self.onlayer+2, randint(1,3), -2)

    def stun(self, duration):
        pass

    def hitted(self, damage, pushed, dmgType):
        # decrease health & no hitback
        if self.health<=0:
            return False
        true_dmg = round(damage*self.realDmgRate)
        self.health -= true_dmg
        self.msgList.append( [getPos(self,0.5,0.5), str(true_dmg), 60] )
        if self.health <= 0:        # broken
            self.health = 0
            self.crushSnd.play(0)
            self.spurtCanvas.addPebbles(self, 6, type="eggDebri")
            return True

    def paint(self, screen):
        # draw shadow
        shadRect = self.rect.copy()
        shadRect.left -= 8
        screen.blit(self.shad, shadRect)
        # draw baby
        if self.health>0:
            screen.blit( self.baby.image, self.baby.rect )
        screen.blit( self.image, self.rect )
        # Hit highlight
        if self.hitBack:
            screen.blit( self.shad, self.rect )

# Goalie ----------------------------
class HellHound(Monster):
    imgLib = None
    shadLib = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLib:
            HellHound.imgLib = {
                "iList": createImgList("image/stg1/hellHound0.png", "image/stg1/hellHound1.png"),
                "jump": createImgList("image/stg1/hellHound_Att.png"),
                "knock": createImgList("image/stg1/hellHound_Land.png")
            }
            HellHound.shadLib = getShadLib(HellHound.imgLib)
            HellHound.mockSnd = pygame.mixer.Sound("audio/wolf.wav")
            HellHound.knockSnd = pygame.mixer.Sound("audio/chichengKnock.wav")
        
        # calculate its position
        Monster.__init__(self, "hellHound", (255,0,0,240), 6, 3, onlayer, sideGroup, bar=True)
        #self.bar = HPBar(self.full, blockVol=200, barH=12)
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top
        self.alterSpeed( choice([1,-1]) )
        self.jumping = False
        self.dealt = False
        self.cnt = 350      # count for the loop of shift position
        self.knockCnt = 0
        self.max_spd = 5    # horrizontal

    def move(self, sprites, canvas, groupList, knock, GRAVITY):
        self.checkHitBack()
        self.count_stun()

        # when knockcnt>0, dealing damage
        if self.knockCnt>0:
            self.knockCnt -= 1
            if not self.dealt:
                if cldList(self, sprites):
                    self.dealt = True
        else:
            if knock:         # on landing, start dealing damage
                self.setImg("knock")
                self.weaponIndx = 2
                self.knockCnt = 18
                self.dealt = False
                self.push = self.pushList[0] if self.direction=="left" else self.pushList[1]
                for i in (0.2,0.4,0.6,0.8):
                    canvas.addSpatters(randint(2,6), [3,5,7], [28,32,36], (30,20,20,210), getPos(self,i,0.99), True)
            # knockCnt = 0的情况，可能的状态有很多
            elif self.combo>0 and not self.jumping:
                self.takeOff(sprites, groupList, GRAVITY)
                self.combo -= 1
            elif self.jumping:    # jumping
                self.setImg("jump")
            else:       # end dealing damage, back to waiting state
                # update image.
                if not (self.cnt % 10):
                    self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                    self.setImg("iList",self.imgIndx)
            self.mask = pygame.mask.from_surface(self.image)
        # flickering yellow
        canvas.addSmoke( 1, (1,2,4), 5, (210,140,20,210), getPos(self,0.5,random()), 60 )
        # count down for rage actions.
        self.cnt -= 1
        if self.cnt<=0:
            self.cnt = randint(280,300)
        if self.jumping:
            self.rect.left += self.speed    # Only consider x here. y is acted by fall()
        elif not self.jumping and self.cnt==240:
            if self.stun_time==0:
                self.takeOff(sprites, groupList, GRAVITY)
                self.combo = randint(1,3)

    def takeOff(self, sprites, groupList, GRAVITY):
        self.mockSnd.play(0)
        tgt = choice(sprites)
        self.jumping = True
        tgtPos, myPos = getPos(tgt,0.5,1), getPos(self,0.5,1)
        # 目标在下方
        if tgt.onlayer-1<self.onlayer:
            self.onlayer -= 2
            self.gravity = -14
            self.alarmTime = self.estimateTime(14, tgtPos[1]-myPos[1], GRAVITY)
        # 否则目标在上方或同行
        else:
            if (tgt.onlayer-1>self.onlayer) and (str(self.onlayer+2) in groupList):
                # need to confirm that new layer is in groupList (in case of hero jump to the highest layer)
                self.onlayer += 2
            self.gravity = -18
            self.alarmTime = self.estimateTime(18, tgtPos[1]-myPos[1], GRAVITY)
        while True:
            try:
                self.initLayer(groupList[str(self.onlayer)], groupList["0"])
            except:
                self.onlayer -= 2
            else:
                break
        x_spd = round( (tgtPos[0]-myPos[0])/self.alarmTime )
        if x_spd<-self.max_spd:
            x_spd = -self.max_spd
        elif x_spd>self.max_spd:
            x_spd = self.max_spd
        self.alterSpeed( x_spd )

    def estimateTime(self, upwardSpd, absVertical, GRAVITY):
        absDistY = 0
        for y in range(upwardSpd+1):     # 计算得上升总高度(此过程用时upwardSod减至0)
            absDistY += y
        downY = abs(absVertical) + absDistY  # 下降总位移
        anaSpd = 0
        estTime = upwardSpd
        while downY>0:
            absDistY += anaSpd
            downY -= anaSpd
            anaSpd = min(anaSpd+1, GRAVITY)
            estTime += 1
        return estTime

    def fall(self, keyLine, groupList, GRAVITY):
        if self.gravity<GRAVITY:
            self.gravity += 1
        self.rect.bottom += self.gravity
        if self.gravity<0:      # Still in upward action, don't check fall!
            return
        while ( pygame.sprite.spritecollide(self, self.wallList, False, collide_mask) ):  # 如果和参数中的物体相撞，则尝试纵坐标-1
            self.rect.bottom -= 1
            self.gravity = 0
            if self.jumping:
                self.knockSnd.play(0)
                self.jumping = False
                return "vib"
        if getPos(self, 0, 0.5)[1] > keyLine:
            self.onlayer  = max(self.onlayer-2, -1)
            self.initLayer( groupList[str(self.onlayer)], groupList["0"] )
            # 更新obstacle砖块
            self.renewObstacle(groupList["0"])
                
    def reset(self):
        self.imgIndx = 0
        self.setImg("iList")
        self.alarmTime = 0
        self.combo = 0

# Boss ------------------------------
class CrimsonDragon(Boss):
    def __init__(self, x, y, onlayer, font):
        # initialize the sprite
        Boss.__init__(self, font, "CrimsonDragon", (255, 0, 0, 240), 0, 3, onlayer, shadOffset=12)
        self.imgLib = {
            "body": createImgList("image/stg1/DragonBody.png")
        }
        self.shadLib = getShadLib(self.imgLib)
        # ----- body part (the core of the CrimsonDragon) ------
        self.setImg("body")
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.rect.left = x
        self.rect.top = y
        # ------------- head part --------------
        self.headLeft = [ load("image/stg1/DragonHead0.png").convert_alpha(), load("image/stg1/DragonHead1.png").convert_alpha(), 
            load("image/stg1/DragonHead2.png").convert_alpha() ]
        self.headRight = [ flip(self.headLeft[0], True, False), flip(self.headLeft[1], True, False), 
            flip(self.headLeft[2], True, False) ]
        self.headR = { "left":[ (0,0.6), (0,0.61), (0,0.62) ], "right":[ (1,0.6), (1,0.61), (1,0.62) ] }    # 分别为左和右时的位置信息
        self.head = Ajunction( self.headLeft[2], getPos(self, self.headR[self.direction][0][0], self.headR[self.direction][0][1]) )
        # ------------- wing part ----------------
        self.wingLeft = [ load("image/stg1/wing0.png").convert_alpha(), load("image/stg1/wing1.png").convert_alpha(), load("image/stg1/wing2.png").convert_alpha(), load("image/stg1/wing3.png").convert_alpha(), 
            load("image/stg1/wing2.png").convert_alpha(), load("image/stg1/wing1.png").convert_alpha(), load("image/stg1/wing0.png").convert_alpha() ]
        self.wingRight = [ flip(self.wingLeft[0], True, False), flip(self.wingLeft[1], True, False), flip(self.wingLeft[2], True, False), flip(self.wingLeft[3], True, False), 
            flip(self.wingLeft[4], True, False), flip(self.wingLeft[5], True, False), flip(self.wingLeft[6], True, False) ]
        self.wingR = { "left":[ (0.5,-0.3), (0.5,-0.21), (0.5,0.1), (0.5,0.3), (0.5,0.1), (0.5,-0.21), (0.5,-0.3) ], "right":[ (0.5,-0.3), (0.5,-0.21), (0.5,0.1), (0.5,0.3), (0.5,0.1), (0.5,-0.21), (0.5,-0.3) ] }
        self.wing = Ajunction( self.wingLeft[0], getPos(self, self.wingR[self.direction][0][0], self.wingR[self.direction][0][1]) )
        # -------------- tail part ---------------
        self.tailLeft = [ load("image/stg1/tail0.png").convert_alpha(), load("image/stg1/tail1.png").convert_alpha(), load("image/stg1/tail2.png").convert_alpha(), 
            load("image/stg1/tail3.png").convert_alpha(), load("image/stg1/tail2.png").convert_alpha(), load("image/stg1/tail1.png").convert_alpha() ]
        self.tailRight = [ flip(self.tailLeft[0], True, False), flip(self.tailLeft[1], True, False), flip(self.tailLeft[2], True, False), 
            flip(self.tailLeft[3], True, False), flip(self.tailLeft[4], True, False), flip(self.tailLeft[5], True, False) ]
        self.tailR = { "left":[ (0.76,0.84), (0.76,0.84), (0.72,0.84), (0.68,0.84), (0.72,0.84), (0.76,0.84) ], "right":[ (0.24,0.84), (0.24,0.84), (0.28,0.84), (0.32,0.84), (0.28,0.84), (0.24,0.84) ] }
        self.tail = Ajunction( self.tailLeft[0], getPos(self, self.tailR[self.direction][0][0], self.tailR[self.direction][0][1]) )
        # ----------- other attributes -------------------------
        self.reset()
        self.nxt = getPos(self, 0.5, 0.5)
        self.growlSnd = pygame.mixer.Sound("audio/redDragonGrowl.wav")
        self.moanSnd = pygame.mixer.Sound("audio/redDragonMoan.wav")
        self.upDown = 3      # 悬停状态身体上下振幅
        self.cnt = 1500      # count for the loop of shift position & rage. should not be stunned!

    def update(self, delay, sprites, canvas):
        self.checkHitBack()
        self._tipPosition(canvas)
        self.count_stun()
        if not (delay % 3):
            if self.shift( self.nxt[0], self.nxt[1] ):
                # 如果处于悬停状态，则随着扇翅上下摆动，and shakes tail。
                if not (delay % 18):
                    self.rect.top += self.upDown
                    self.upDown = - self.upDown
                    self.tailIndx = (self.tailIndx+1)%len(self.tailLeft)
            self.wingIndx = (self.wingIndx+1) % len(self.wingLeft)
            self.setImg("body")
            if self.direction == "left":
                self.head.updateImg( self.headLeft[self.headIndx] )
                self.wing.updateImg( self.wingLeft[self.wingIndx] )
                self.tail.updateImg( self.tailLeft[self.tailIndx] )
            elif self.direction == "right":
                self.head.updateImg( self.headRight[self.headIndx] )
                self.wing.updateImg( self.wingRight[self.wingIndx] )
                self.tail.updateImg( self.tailRight[self.tailIndx] )
            self.mask = pygame.mask.from_surface(self.image)
            self.head.updatePos( getPos(self, self.headR[self.direction][self.headIndx][0], self.headR[self.direction][self.headIndx][1]) )
            self.wing.updatePos( getPos(self, self.wingR[self.direction][self.wingIndx][0], self.wingR[self.direction][self.wingIndx][1]) )
            self.tail.updatePos( getPos(self, self.tailR[self.direction][self.tailIndx][0], self.tailR[self.direction][self.tailIndx][1]) )
        
        if self.stun_time==0:
            # count down for rage actions.
            self.cnt -= 1
            if self.cnt<=0:
                self.cnt = 1700
            elif self.cnt>=240:
                if not self.cnt%60:
                    self.nxt = ( randint(100,640), randint(80,520) )   # randomize a new position
                    self.direction = "left" if ( self.nxt[0] < getPos(self, 0.5, 0.5)[0] ) else "right"
            else:
                self.nxt = ( 520, 80 )
                self.direction = "left"
                if not self.cnt%8:
                    return self.makeFire( sprites )
            # deal regular fire attack:
            self.headIndx = 0
            if not (self.cnt % 12) and self.coolDown<=0 and random()<0.26:
                self.growlSnd.play(0)
                self.coolDown = 90
                return self.makeFire( sprites )
            elif self.coolDown > 0:
                self.coolDown -= 1
                if self.coolDown >= 84:
                    self.headIndx = 1
                elif self.coolDown >= 78:
                    self.headIndx = 2
                elif self.coolDown >= 72:
                    self.headIndx = 1
            return None
    
    def makeFire(self, sprites):
        tgt = choice( sprites )
        aim = getPos( tgt,0.5,0.5 )
        deltaX = aim[0] - getPos( self.head, 0.5, 0.5 )[0]
        deltaY = aim[1] - getPos( self.head, 0.5, 0.5 )[1]
        time = round( ( deltaX**2 + deltaY**2 )**0.5 / 6 )
        spdX = round( deltaX/time )
        spdY = round( deltaY/time )
        degree = math.degrees( math.atan2(spdY, spdX) )      # 两点线段的弧度值，并弧度转角度
        fire = RedDragonFire( getPos(self.head,0.2,0.6), (spdX, spdY), tgt.onlayer-1, degree ) if self.direction=="left" else RedDragonFire( getPos(self.head,0.8,0.6), (spdX, spdY), tgt.onlayer-1, degree )
        return fire

    def paint(self, screen):
        '''鉴于本对象的构造非常复杂，因此提供一个专门的绘制接口
            给此函数传递一个surface参数，即可在该surface上绘制（blit）完整的本对象'''
        # draw shadow
        shadRect = self.rect.copy()
        shadRect.left -= self.shadOffset
        screen.blit(self.shad, shadRect)
        # draw self
        screen.blit( self.tail.image, self.tail.rect )
        screen.blit( self.image, self.rect )
        screen.blit( self.head.image, self.head.rect )
        screen.blit( self.wing.image, self.wing.rect )
        # Hit highlight
        if self.hitBack:
            screen.blit( self.shad, self.rect )
    
    def reset(self):
        self.headIndx = 0
        self.wingIndx = 0
        self.tailIndx = 0
        self.coolDown = 0    # count for attack coolDown

    def erase(self):
        self.moanSnd.play(0)
        self.head.kill()
        self.wing.kill()
        del self.head, self.wing
        self.kill()
        return True   # dead

    def shift(self, final_x, final_y):
        x = self.rect.left + self.rect.width/2
        y = self.rect.top + self.rect.height/2
        if (x == final_x) or (y == final_y):
            return True   # 表示已到目标
        maxSpan = 8
        spd = 4
        dist = 0
        if (x < final_x):
            dist = math.ceil( (final_x - x)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.left += dist
        elif (x > final_x):
            dist = math.ceil( (x - final_x)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.left -= dist
        if (y < final_y):
            dist = math.ceil( (final_y - y)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.top += dist
        elif (y > final_y):
            dist = math.ceil( (y - final_y)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.top -= dist
        return False    # 表示未到目标

class RedDragonFire(InanimSprite):
    def __init__(self, pos, spd, layer, degree):   # 参数pos为本对象初始的位置
        InanimSprite.__init__(self, "fire")
        self.imageList = [ pygame.transform.rotate( load("image/stg1/fire.png").convert_alpha(), -degree ), 
            pygame.transform.rotate( load("image/stg1/fire.png").convert_alpha(), degree ) ]
        self.imgIndx = 0
        self.image = self.imageList[0]
        self.rect = self.image.get_rect()
        self.rect.left = pos[0]-self.rect.width//2
        self.rect.top = pos[1]-self.rect.height//2
        self.mask = pygame.mask.from_surface(self.image)
        self.speed = spd
        if spd[0]>0:
            self.push = 9
        else:
            self.push = -9
        self.damage = MB["CrimsonDragon"].damage
        self.dmgType = MB["CrimsonDragon"].dmgType
        self.blastSnd = pygame.mixer.Sound("audio/wizard/hit.wav")
        self.onlayer = layer

    def update(self, delay, sideWalls, downWalls, keyLine, sprites, canvas, bg_size):
        if pygame.sprite.spritecollide(self, downWalls, False, collide_mask) or pygame.sprite.spritecollide(self, sideWalls, False, collide_mask):
            self._explode(canvas)
            return "vib"
        # generate some sparks
        canvas.addTrails( [4,5,6], [20,24,28], (240,160,20,210), getPos(self, 0.3+random()*0.4, 0.3+random()*0.4) )
        if not delay%4:
            self.imgIndx = (self.imgIndx+1) % len(self.imageList)
            self.image = self.imageList[self.imgIndx]
            self.mask = pygame.mask.from_surface(self.image)
            canvas.addTrails( [4,5,6], [10,12,14], (120,90,30,190), getPos(self,0.5,0.5) )
        if cldList(self, sprites):
            self._explode(canvas)
            return "vib"
        # move the object
        self.rect.left += self.speed[0]
        self.rect.top += self.speed[1]
        return None

    def _explode(self, canvas):
        self.blastSnd.play(0)
        canvas.addExplosion(getPos(self,0.5,0.5), 30, 15)
        canvas.addSmoke( 6, (4, 6, 8), 2, (2,2,2,240), getPos(self,0.5,0.5), 4 )
        self.kill()
        del self
        return


# ========================================================================
# --------------------------------- CP 2 ---------------------------------
# ========================================================================
class Column(InanimSprite):
    def __init__(self, bg_size):
        InanimSprite.__init__(self, "column")
        self.image = load("image/stg2/column.png").convert_alpha()
        self.alarmList = [ load("image/stg2/alarm0.png").convert_alpha(), load("image/stg2/alarm1.png").convert_alpha(), 
            load("image/stg2/alarm2.png").convert_alpha(), load("image/stg2/alarm3.png").convert_alpha(), 
            load("image/stg2/alarm4.png").convert_alpha(), load("image/stg2/alarm5.png").convert_alpha() ]
        self.alarmRect = None
        self.rect = self.image.get_rect()
        self.mask = pygame.mask.from_surface(self.image)
        self.width = bg_size[0]
        self.height = bg_size[1]
        self.damage = NB["column"]["damage"]
        self.dmgType = "physical"
        self.speed = 8
        self.aim = [0, 0]     # 当delay重置为0时就获取并更新hero的中心坐标
        self.rect.right = 0
        self.rect.bottom = 0  # 初始位置于屏幕左上角 （每个区域都有一个，因此其他区域的会保持在此处一段时间）
        self.t = 260          # 循环时间周期，可在main中动态调整以改变游戏难度
        self.delay = self.t-30 # index that controll the fall and wait (there would be 0.5 sec before the first fall)
        self.dustCnt = -1
        self.status = None
        self.hitSnd = pygame.mixer.Sound("audio/crush.wav")

    def update(self, sprites, frnLayer, groupList, spurtCanvas):
        self.delay = ( self.delay + 1 ) % self.t
        # 确认目的地 (0为等待目的地的状态)
        if ( self.delay == 0 ):
            tgt = choice(sprites)
            if tgt.aground:
                # 英雄在落地状态，可以进行攻击。但首先需要判断自己的真正落点（必须落在linewall上，不能悬空）。
                self.aim[0] = tgt.rect.left + tgt.rect.width // 2
                self.aim[1] = tgt.rect.bottom
                aimLayer = tgt.onlayer-1   # 这里采用砖块的行数系统（奇数），以方便查找最终落点
                flag = False               # 修改位
                while (not flag) and (str(aimLayer) in groupList):
                    #遍历该层所有行砖，检查是否可以落在该行上
                    for wall in groupList[str(aimLayer)]:
                        if wall.rect.left <= self.aim[0] <= wall.rect.right:
                            self.aim[1] = wall.rect.top
                            flag = True
                            break
                    aimLayer -= 2
            else:
                return
        # 警告阶段 (1~33)
        elif ( 1 <= self.delay < 34 ):
            self.status = "alarm"
            return
        # 开始下落（34时刻reset）
        elif ( self.delay == 34 ):
            if ( frnLayer >= 30 and self.t >= 260 ) or ( frnLayer >= 60 and self.t >= 240 ) or ( frnLayer >= 90 and self.t >= 220 ):
                self.t -= 20
            self.rect.left = self.aim[0] - self.rect.width//2
            self.rect.bottom = 0
            self.status = "falling"
            return
        # 下落中（34时刻以后首先进入falling状态）
        elif (self.status=="falling"):
            self.rect.bottom += self.speed
            if not self.delay%DMG_FREQ:
                for each in sprites:
                    if ( collide_mask( self, each ) ):
                        if each.rect.left+each.rect.width//2 > self.rect.left+self.rect.width//2:
                            each.hitted(self.damage, 3, self.dmgType)
                        else:
                            each.hitted(self.damage, -3, self.dmgType)
            if ( self.rect.bottom >= self.aim[1] ):  # 抵达落点
                self.hitSnd.play(0)
                # 炸开
                spurtCanvas.addPebbles( self, 9 )
                spurtCanvas.addSpatters(6, [3,5,7], [24,28,32], (80,80,110), getPos(self,0.5,0.6), falling=True)
                self.dustCnt = 0
                self.status = "ash"
                return "vib"
        # 抵达落点后
        else:
            if self.dustCnt == 47:
                self.dustCnt = -1
                self.alarmRect = None
            elif (self.dustCnt >= 0) and (self.dustCnt < 47):
                self.alarmRect = self.alarmList[ (self.dustCnt)//8 ].get_rect()  # 获取新的图片的rect
                self.alarmRect.left = self.aim[0] - self.alarmRect.width // 2  # 设定x位置
                self.alarmRect.bottom = self.aim[1]  # 设定y位置
                self.dustCnt += 1
    
    def paint(self, surface):
        if self.status == "falling":
            surface.blit( self.image, self.rect )
        # 特殊阶段额外paint
        if self.status == "alarm":
            pygame.draw.line( surface, (0,160,210), (self.aim[0],0), (self.aim[0],self.aim[1]), randint(1,4))
        elif self.status == "ash" and self.alarmRect:
            surface.blit( self.alarmList[ (self.dustCnt)//8 ], self.alarmRect )

    def lift(self, dist, limit=False):
        self.rect.bottom += dist
        self.aim[1] += dist

    def level(self, dist):
        self.rect.left += dist
        self.aim[0] += dist

# -----------------------------------
class Bat(Monster):
    imgLib = None
    shadLib = None

    def __init__(self, wallGroup, onlayer):
        if not self.imgLib:
            Bat.imgLib = {
                "hang": createImgList("image/stg2/batHang.png"),
                "flyList": createImgList("image/stg2/bat0.png","image/stg2/bat1.png")
            }
            Bat.shadLib = getShadLib(Bat.imgLib)
        
        # calculate its position
        Monster.__init__(self, "bat", (80,10,80,240), 3, 1, onlayer)
        self.wallList = []       # 存储本行的所有砖块; # 每次初始化一个新实例时，清空此类的wallList（否则会在上一个实例的基础上再加！）
        posList = []             # 辅助列表，用于暂时存储本行砖块的位置（左边线）
        for aWall in wallGroup:  # 由于spriteGroup不好进行索引/随机选择操作，因此将其中的sprite逐个存入列表中存储
            #if not aWall.category == "specialWall":
            self.wallList.append(aWall)
            posList.append(aWall.rect.left)
        if len(self.wallList)==0:
            self.kill()
            return
        wall = choice(self.wallList)
        self.onlayer = int(onlayer)
        self.foot = wall.rect.bottom - 8
        # initialize the sprite ---------------
        self.imgIndx = 0
        self.setImg("hang")
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left + (wall.rect.width-self.rect.width) // 2
        self.rect.top = self.foot
        self.damage = MB["bat"].damage
        self.coolDown = 0
        self.speed = [0, 0]
        self.vib = 2
        self.tgt = None      # tgt将取三类值：None表示休息中；hero对象表示追击敌人；lineWall对象表示从飞行状态转入休息的短暂动作。
    
    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        # 睡眠状态。若有hero接近，则将之唤醒。
        if not self.tgt:
            for each in sprites:
                if math.pow( getPos(each,0.5,0.5)[0]-getPos(self,0.5,0.5)[0], 2 ) + math.pow( getPos(each,0.5,0.5)[1]-getPos(self,0.5,0.5)[1], 2 )<100**2:
                    self.tgt = each
                    self.imgIndx = 0
                    break
        # 有tgt的飞行状态，又分为两类：
        else:
            myPos = getPos(self, 0.5, 0.5)
            tgtPos = getPos(self.tgt, 0.5, 0.5)
            # tgt引用的是砖块，表示飞向最近的砖块，并悬停在下面。
            if self.tgt.category in ("lineWall", "specialWall"):
                if ( self.tgt.rect.left < myPos[0] < self.tgt.rect.right ) and ( self.rect.top <= self.foot ):
                    self.tgt = None
                    trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]
                    self.setImg("hang")
                    self.rect = self.image.get_rect()
                    self.rect.left = trPos[0]-self.rect.width//2
                    self.rect.bottom = trPos[1]
                    self.imgIndx = 0
                    return
                elif myPos[0] < tgtPos[0]:
                    self.speed[0] = 1
                elif myPos[0] > tgtPos[0]:
                    self.speed[0] = -1
            # tgt引用的是hero，则为追击模式！
            elif self.tgt.category=="hero":
                # 检查：目标死亡；或距离过大，丢失目标
                if (self.tgt.health <= 0) or math.pow( tgtPos[0]-myPos[0], 2 ) + math.pow( tgtPos[1]-myPos[1], 2 )>160**2:
                    if len(self.wallList)==0:
                        self.kill()
                        return
                    # 先初始化为任意一块。
                    w = choice(self.wallList)
                    dist = abs( myPos[0]-getPos(w,0.5,0.5)[0] )
                    self.tgt = w
                    # 比较距离，找出最近的砖块。
                    for each in self.wallList:
                        newDist = abs( myPos[0]-getPos(each,0.5,0.5)[0] )
                        if newDist < dist:
                            dist = newDist
                            self.tgt = each
                    return
                elif not delay%3:       # 继续追击
                    if myPos[0] < tgtPos[0]:
                        self.speed[0] = 1
                    elif myPos[0] > tgtPos[0]:
                        self.speed[0] = -1
                    else:
                        self.speed[0] = 0
            # Move the bat.
            if not delay%2:
                if abs(self.speed[1]) > 6:
                    self.vib = -self.vib
                self.speed[1] += self.vib
                if self.stun_time==0:
                    self.rect.left += self.speed[0]
                self.rect.top += self.speed[1]
                # Change image.
                if not (delay % 8):
                    trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]
                    self.setImg("flyList",self.imgIndx)
                    self.rect = self.image.get_rect()
                    self.rect.left = trPos[0]-self.rect.width//2
                    self.rect.bottom = trPos[1]
                    self.mask = pygame.mask.from_surface(self.image)    # 更新mask，使得与hero重合的判断更加精确
                    self.imgIndx = (self.imgIndx+1) % len(self.imgLib["flyList"])
            # deal damage.
            if self.stun_time==0:
                if self.coolDown==0:
                    for each in sprites:
                        if collide_mask(self, each):
                            self.coolDown = 16
                else:
                    if self.coolDown == 12:
                        cldList( self, sprites )
                    self.coolDown -= 1

    def lift(self, dist):
        self.rect.bottom += dist
        self.foot += dist

# -----------------------------------
class Golem(Monster):
    imgLib = None
    shadLib = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLib:
            Golem.imgLib = {
                "iList": createImgList("image/stg2/golemLeft0.png", "image/stg2/golemLeft1.png"),#, "image/stg2/golemLeft2.png"),
                "attList": createImgList("image/stg2/golemLAtt0.png", "image/stg2/golemLAtt1.png"),
                "crushList": createImgList("image/stg2/crush0.png", "image/stg2/crush1.png", "image/stg2/crush2.png")
            }
            Golem.shadLib = getShadLib(Golem.imgLib)
        
        # calculate its position
        Monster.__init__(self, "golem", (240,240,255,240), 8, 4, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top
        self.doom = 0
        self.alterSpeed( choice([-1, 1]) )

    def move(self, delay, sprites):
        if self.health>0:
            self.checkHitBack(obstacle=True)
            self.count_stun()
            
            if self.stun_time==0:
                # 运动
                if not (delay%2):
                    self.rect.left += self.speed
                    if (getPos(self,0.75,0)[0] >= self.scope[1] and self.speed > 0) or (getPos(self,0.25,0)[0] <= self.scope[0] and self.speed < 0):
                        self.alterSpeed(-self.speed)
                    # 更新图片
                    if self.coolDown<40 and not ( delay % 20 ):
                        self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                        self.setImg("iList",self.imgIndx)
                # 检查攻击
                if self.coolDown == 0:
                    for each in sprites:
                        if ( collide_mask(self, each) ):
                            self.coolDown = 60
                elif (self.coolDown > 0):
                    self.coolDown -= 1
                    self.bite(sprites)
        else:
            self.doom += 1
            if self.doom == 22:
                mite1 = Golemite( self.rect, self.scope, "left", self.onlayer, self.obstacle )
                mite2 = Golemite( self.rect, self.scope, "right", self.onlayer, self.obstacle )
                self.kill()
                return ( mite1, mite2 )
            elif self.doom == 15:
                self.setImg("crushList",2)
            elif self.doom == 8:
                self.setImg("crushList",1)
            elif self.doom == 1:
                self.setImg("crushList",0)
                self.spurtCanvas.addPebbles(self, 4)
    
    def bite(self, sprites):
        # deal damage
        if (self.coolDown >= 49):
            self.attIndx = 0    # 60-49蓄力图片
        elif (self.coolDown >= 40):
            self.attIndx = 1    # 48-40咬合图片
            if ( self.coolDown == 48 ):
                cldList( self, sprites )
        else: 
            return
        # switch image
        self.setImg("attList",self.attIndx)
    
    def reset(self):
        self.imgIndx = 0
        self.attIndx = 0
        self.setImg("iList",0)
        self.coolDown = 0

    def hitted(self, damage, pushed, dmgType):
        if pushed>0:   # 向右击退
            self.hitBack = max( pushed-self.weight, 0 )
        elif pushed<0: # 向左击退
            self.hitBack = min( pushed+self.weight, 0 )
        if self.health>0:
            true_dmg = round(damage*self.realDmgRate)
            self.health -= true_dmg
            self.msgList.append( [getPos(self,0.5,0.5), str(true_dmg), 60] )
            if self.health <= 0:
                self.health = 0
                return True
        else:
            return False    # 处于分裂小哥伦的状态，此时不应计算伤害

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

class Golemite(Monster):
    imgLib = None
    shadLib = None

    def __init__(self, rect, scope, direct, onlayer, sideGroup):
        if not self.imgLib:
            Golemite.imgLib = {
                "iList": createImgList("image/stg2/golemiteLeft0.png","image/stg2/golemiteLeft1.png","image/stg2/golemiteLeft0.png","image/stg2/golemiteLeft2.png")
            }
            Golemite.shadLib = getShadLib(Golemite.imgLib)
        
        Monster.__init__(self, "golemite", (240,240,255,240), 4, 2, onlayer, sideGroup, debri=("pebble",2))
        self.category = "golem"
        self.scope = scope
        self.reset()
        if direct == "left":
            self.alterSpeed(-1)
        else:
            self.alterSpeed(1)
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = rect.left+ rect.width//2 - self.rect.width//2
        self.rect.bottom = rect.bottom
        self.doom = 0
    
    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        if self.stun_time==0:
            # deal move
            if not delay % 2:
                self.rect.left += self.speed
                if (getPos(self,0.75,0)[0] >= self.scope[1] and self.speed > 0) or (getPos(self,0.25,0)[0] <= self.scope[0] and self.speed < 0):
                    self.alterSpeed(-self.speed)
            if not delay % 8:
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                self.setImg("iList",self.imgIndx)
            # deal attack
            if self.coolDown == 0:
                for each in sprites:
                    if ( collide_mask(self, each) ):
                        self.coolDown = 60
            if (self.coolDown > 0):
                self.coolDown -= 1
                if ( self.coolDown == 45 ):
                    cldList( self, sprites )
            
    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.coolDown = 0

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

# -----------------------------------
class Bowler(Monster):
    imgLib = None
    shadLib = None

    def __init__(self, wallGroup, sideGroup, onlayer):
        if not self.imgLib:
            Bowler.imgLib = {
                "iList": createImgList("image/stg2/bowler0.png","image/stg2/bowler0.png","image/stg2/bowler0.png","image/stg2/bowler1.png"),
                "throw": createImgList("image/stg2/bowlerThrow.png")
            }
            Bowler.shadLib = getShadLib(Bowler.imgLib)
        
        # calculate its position
        Monster.__init__(self, "bowler", (10,60,80,240), 0, 4, onlayer, sideGroup)
        # note： 这里bowler的onlayer，以及其stone的onlayer值均为砖的行数，并非自身的行数，使用时不需要-1操作
        self.wallList = []       # 存储本行的所有砖块;
        for aWall in wallGroup:  # 由于spriteGroup不好进行索引/随机选择操作，因此将其中的sprite逐个存入列表中存储
            self.wallList.append(aWall)
        wall = choice(self.wallList)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top

    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        if self.stun_time==0:
            if not (delay % 60 ):
                heroX = choice(sprites).rect.left
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]
                if self.rect.left > heroX:
                    self.direction = "left"
                else:
                    self.direction = "right"
                self.setImg("iList",self.imgIndx)
                self.rect = self.image.get_rect()
                self.rect.left = trPos[0]-self.rect.width//2
                self.rect.bottom = trPos[1]

    def throw(self, delay):
        if not (delay % 120) and (random() > 0.5):  # 控制投石频率
            trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]
            self.setImg("throw")
            self.rect = self.image.get_rect()
            self.rect.left = trPos[0]-self.rect.width//2
            self.rect.bottom = trPos[1]
            return Stone((self.rect.left, self.rect.bottom), self.onlayer, self.direction)

    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)

class Stone(InanimSprite):
    crushSnd = None

    def __init__(self, pos, onlayer, direction):
        if not Stone.crushSnd:
            Stone.crushSnd = pygame.mixer.Sound("audio/wizard/hit.wav")
        InanimSprite.__init__(self, "stone")
        self.coin = 0
        self.bldColor = (160,160,180,240)
        self.weight = 1

        self.image = load("image/stg2/stone.png").convert_alpha()
        self.oriImage = self.image
        self.deg = 0
        self.rect = self.image.get_rect()
        self.mask = pygame.mask.from_surface(self.image)
        self.damage = MB["stone"].damage
        self.rect.left = pos[0]
        self.rect.bottom = pos[1]
        self.onlayer = int(onlayer)
        self.gravity = 1
        self.speed = -2 if direction == "left" else 2   # 负数表示向左，正数向右
        self.health = MB["stone"].health
        self.manner = MB["stone"].manner

    def update(self, delay, sideWalls, downWalls, keyLine, sprites, canvas):
        self.rect.left += self.speed
        # 次数用尽，撞毁
        if ( self.health <= 0 ):
            canvas.addPebbles(self, 4)
            self.crushSnd.play(0)
            self.kill()
            del self
            return
        if not (delay % 4):
            self.deg = (self.deg+20) % 360
            self.image = rot_center(self.oriImage, self.deg) if self.speed <= 0 else rot_center(self.oriImage, -self.deg)
        # 水平撞击
        if not delay%DMG_FREQ:
            for each in sprites:
                if ( collide_mask(self, each) ):
                    pos = getPos(self, 0, 0.6) if self.speed<0 else getPos(self, 1, 0.6)
                    canvas.addSpatters(2, (2,3,4), (6,7,8), (40,40,40,255), pos, False)
                    push = -8 if (self.speed<0) else 8
                    each.hitted(self.damage, push, "physical")
        if ( pygame.sprite.spritecollide(self, sideWalls, False, collide_mask) ) or ( pygame.sprite.spritecollide(self, downWalls, False, collide_mask) ):
            # 和英雄的处理方法一样，尝试纵坐标-4，再看是否还会碰撞。4以内的高度都可以自动滚上去
            self.rect.top -= 4
            if getCld(self, downWalls, ["lineWall","specialWall"]) or getCld(self, sideWalls, ["baseWall","sideWall","hollowWall"]):
                pos = getPos(self, 0, 0.6) if self.speed<0 else getPos(self, 1, 0.6)
                canvas.addSpatters(4, (2,4,6), (6,7,8), (40,40,40,255), pos, True)
                self.rect.top += 4
                self.rect.left -= self.speed
                self.speed = - self.speed
                self.hitted(50, 0, "physical")
        # 下落
        self.rect.bottom += self.gravity
        while ( pygame.sprite.spritecollide(self, downWalls, False, collide_mask) ):
            # 当下落速度达到最大的7时，碰撞降低耐久
            if self.gravity==7:
                self.hitted(100, 0, "physical")
                self.gravity = 1
                self.crushSnd.play(0)
            self.rect.bottom -= 1
            if not ( pygame.sprite.spritecollide(self, downWalls, False, collide_mask) ): # 如果不再和wall有重合
                canvas.addSpatters(1, (2,3,4), (5,6,7), (40,40,40,255), getPos(self,0.5,1), False)
                self.gravity = 1
                return False
        if (self.gravity <= 6):
            self.gravity += 1
        if ( self.rect.top >= keyLine ):
            self.onlayer = max(self.onlayer-2, -1)
    
    def stun(self, duration):
        pass

    def hitted(self, damage, pushed, dmgType):
        if pushed>0:   # 向右击退
            self.hitBack = max( pushed-self.weight, 0 )
        elif pushed<0: # 向左击退
            self.hitBack = min( pushed+self.weight, 0 )
        self.health -= damage
    
    def drawHealth(self, surface):
        pass

# -----------------------------------
class Spider(Monster):
    imgLib = None
    shadLib = None

    def __init__(self, y, onlayer, boundaries_x, boundaries_y):
        if not self.imgLib:
            Spider.imgLib = {
                "body": createImgList("image/stg2/miniSpider0.png", "image/stg2/miniSpider1.png")
            }
            Spider.shadLib = getShadLib(Spider.imgLib)
        
        # calculate its position
        Monster.__init__(self, "spider", (180,10,80,240), 3, 1, onlayer, shadOffset=4)

        self.scope_x = boundaries_x
        self.scope_y = boundaries_y
        self.reset()
        self.setImg("body",0)
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.rect.left = randint(self.scope_x[0], self.scope_x[1]-self.rect.width)
        self.rect.top = y
        self.speed = [-3,3]     # initial: left, down
        # ----------- other attributes -------------------------
        self.doom = 0
        self.webSnd = pygame.mixer.Sound("audio/spitWeb.wav")
        self.upDown = 1
        self.haltCnt = randint(20,60)

    def move(self, delay, sprites):
        self.checkHitBack()
        self.count_stun()
        if self.haltCnt>0:
            self.haltCnt -= 1
        # update image and move 
        if not delay % 2:
            # move
            if self.haltCnt==0:
                if self.stun_time==0:
                    self.rect.left += self.speed[0]
                    if (self.rect.right >= self.scope_x[1] and self.speed[0] > 0) or (self.rect.left <= self.scope_x[0] and self.speed[0] < 0):
                        self.speed[0] = -self.speed[0]                
                    self.rect.top += self.speed[1]
                    if (self.rect.bottom >= self.scope_y[1] and self.speed[1] > 0) or (self.rect.top <= self.scope_y[0] and self.speed[1] < 0):
                        self.speed[1] = -self.speed[1]
                    # 随机停一会或变方向
                    if not delay%24 and random()<0.1:
                        dice = random()
                        if dice<0.2:
                            self.haltCnt = 60
                        elif dice<0.6:
                            self.speed[0] = -self.speed[0]
                        else:
                            self.speed[1] = - self.speed[1]
                if not delay%8:
                    self.rect.top += self.upDown
                    self.upDown = -self.upDown
                    # 根据速度方向计算出需要rotate的degree，rotate the image
                    self.imgIndx = (self.imgIndx+1) % len(self.imgLib["body"]["left"])
                    self.setImg("body", indx=self.imgIndx)
                    tmpPos = getPos(self, 0.5, 0.5)
                    degree = math.degrees( math.atan2(self.speed[0], self.speed[1]) )
                    self.image = pygame.transform.rotate( self.image, degree )
                    self.rect = self.image.get_rect()
                    self.rect.left = tmpPos[0]-self.rect.width//2
                    self.rect.top = tmpPos[1]-self.rect.height//2
                    self.shad = pygame.transform.rotate( self.shad, degree )
                    self.mask = pygame.mask.from_surface(self.image)
            if self.speed[0]>0:
                self.direction = "right"
            elif self.speed[0]<0:
                self.direction = "left"
        if self.stun_time==0:
        # Deal Bite.
            if self.coolDown == 0:
                for each in sprites:
                    if ( collide_mask(self, each) ):
                        self.coolDown = 45
                        self.haltCnt = 30
            if (self.coolDown > 0):
                self.coolDown -= 1
                if (self.coolDown == 36):
                    cldList( self, sprites )

    def reset(self):
        self.imgIndx = 0
        self.coolDown = 0    # count for attack coolDown

    def lift(self, dist):
        self.rect.bottom += dist
        self.scope_y = (self.scope_y[0]+dist, self.scope_y[1]+dist)

    def level(self, dist):
        self.rect.left += dist
        self.scope_x = (self.scope_x[0]+dist, self.scope_x[1]+dist)
    
# Boss ------------------------------
class GiantSpider(Boss):

    def __init__(self, y, onlayer, boundaries_x, boundaries_y, font):
        # initialize the sprite
        Boss.__init__(self, font, "GiantSpider", (250,80,120,240), 8, 3, onlayer, shadOffset=4)
        self.scope_x = boundaries_x
        self.scope_y = boundaries_y
        # ----- body part (the core of the CrimsonDragon) ------
        self.imgLib = {
            "body": createImgList("image/stg2/spiderBody.png"),
            "bite": createImgList("image/stg2/spiderBite.png")
        }
        self.shadLib = getShadLib(self.imgLib)
        self.imgIndx = 0
        self.setImg("body")
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.rect.left = randint(self.scope_x[0], self.scope_x[1]-self.rect.width)
        self.rect.bottom = y
        self.speed = [-12,12]     # initial: left, down
        # ----------------- legs part ------------------
        self.legLeft = [ load("image/stg2/leg0.png").convert_alpha(), load("image/stg2/leg1.png").convert_alpha(), 
            load("image/stg2/leg0.png").convert_alpha(), flip(load("image/stg2/leg1.png").convert_alpha(), True, False) ]
        self.legRight = [ flip(self.legLeft[0], True, False), flip(self.legLeft[1], True, False), 
            flip(self.legLeft[2], True, False), flip(self.legLeft[3], True, False) ]
        # Spider's legs are a bit complex! Four directions are respectively set up.
        self.legR = { 
            "left":{ "down": [(0.36,0.72), (0.36,0.62), (0.36,0.72), (0.45,0.66)], "up":[(0.3,0.36), (0.4,0.38), (0.3,0.36), (0.36,0.44)] },
            "right": { "down": [(0.62,0.72), (0.62,0.62), (0.62,0.72), (0.62,0.7)], "up":[(0.73,0.36), (0.63,0.36), (0.73,0.36), (0.68,0.38)] }
        }
        theR = self.legR[self.direction]["down"][0]
        self.leg = Ajunction( self.legLeft[2], getPos(self, theR[0], theR[1]) )
        # ----------- other attributes -------------------------
        self.doom = False
        self.reset()
        self.webSnd = pygame.mixer.Sound("audio/spitWeb.wav")
        self.moanSnd = pygame.mixer.Sound("audio/redDragonMoan.wav")
        self.upDown = 1
        self.parti = None
        self.haltCnt = 0

    def move(self, delay, sprites, canvas):
        self.checkHitBack()
        self._tipPosition(canvas)
        self.count_stun()
        
        if self.doom:
            childList = []
            for i in range(8):
                spider = Spider(randint(self.rect.top,self.rect.bottom), self.onlayer, self.scope_x, self.scope_y)
                spider.rect.left = randint(self.rect.left-20, self.rect.right-self.rect.width+20)
                spider.coin = 0
                childList.append(spider)
                canvas.addSpatters(6, (2,4,6), (12,14,16), (255,20,20), getPos(spider,0.5,0.5))
            # dead
            self.moanSnd.play(0)
            self.leg.kill()
            del self.leg
            self.kill()
            return childList
        if self.haltCnt >0:
            self.haltCnt -= 1
        # update image and move 
        if not delay % 2:
            if not delay%6:
                self.rect.top += self.upDown
                self.upDown = -self.upDown
            if not ( delay % 8 ):
                if self.stun_time==0:
                    # Randomly spit webs
                    if not self.parti and random()<0.05:
                        self.webSnd.play(0)
                        self.haltCnt = 60
                        # filter out those are not hero
                        true_hero = []
                        for each in sprites:
                            if each.category in ("hero","servant"):
                                true_hero.append(each)
                        rect = choice(true_hero).rect.copy()
                        startPos = getPos(self,0.5,0.5)
                        finalPos = [rect.left+rect.width//2, rect.top+rect.height//2]
                        speedX = round( (finalPos[0] - startPos[0]) / 40 )
                        speedY = round( (finalPos[1] - startPos[1]) / 40 )
                        if abs(speedY<=10):  # 距离太远就算了
                            self.parti = [startPos, (speedX, speedY), rect]
                    # move
                    if self.haltCnt==0:
                        self.rect.left += self.speed[0]
                        if (self.rect.right >= self.scope_x[1] and self.speed[0] > 0) or (self.rect.left <= self.scope_x[0] and self.speed[0] < 0):
                            self.speed[0] = -self.speed[0]
                        if self.speed[0]>0:
                            self.direction = "right"
                        elif self.speed[0]<0:
                            self.direction = "left"
                        
                        self.rect.top += self.speed[1]
                        if (self.rect.bottom >= self.scope_y[1] and self.speed[1] > 0) or (self.rect.top <= self.scope_y[0] and self.speed[1] < 0):
                            self.speed[1] = -self.speed[1]
                        # 随机停一会
                        if random()<0.01:
                            self.haltCnt = 60
                    
                        # 根据速度方向计算出需要rotate的degree，rotate the image
                        if self.coolDown>=36:
                            self.setImg("bite")
                        else:
                            self.setImg("body")
                        tmpPos = getPos(self, 0.5, 0.5)
                        degree = math.degrees( math.atan2(self.speed[0], self.speed[1]) )
                        self.image = pygame.transform.rotate( self.image, degree )
                        self.rect = self.image.get_rect()
                        self.rect.left = tmpPos[0]-self.rect.width//2
                        self.rect.top = tmpPos[1]-self.rect.height//2
                        self.shad = pygame.transform.rotate( self.shad, degree )
                        self.mask = pygame.mask.from_surface(self.image)
                        # deal legs:
                        self.legIndx = (self.legIndx+1) % len(self.legLeft)
                        if self.direction == "left":
                            self.leg.updateImg( pygame.transform.rotate( self.legLeft[self.legIndx], degree) )
                        elif self.direction == "right":
                            self.leg.updateImg( pygame.transform.rotate( self.legRight[self.legIndx], degree ) )
            # Set relative position.
            if self.speed[1]>0:
                theR = self.legR[self.direction]["down"][self.legIndx]
            elif self.speed[1]<0:
                theR = self.legR[self.direction]["up"][self.legIndx]
            self.leg.updatePos( getPos(self, theR[0], theR[1]) )
        
        # Deal Bite.
        if self.coolDown == 0:
            for each in sprites:
                if ( collide_mask(self, each) ):
                    self.coolDown = 60
                    self.haltCnt = 30
        if (self.coolDown > 0):
            self.coolDown -= 1
            if (self.coolDown == 42):
                cldList( self, sprites )
        
        # move particle if there is one
        if self.parti:
            pos, speed, rect = self.parti
            self.parti[0] = (pos[0]+speed[0], pos[1]+speed[1])
            canvas.addTrails( [4,5,6], [14,16,18], (250,250,250,210), self.parti[0] )
            if (rect.left<=self.parti[0][0]<=rect.right) and (rect.top<=self.parti[0][1]<=rect.bottom):
                canvas.addSpatters( 5, (2,3,4), (12,14,16), (250,250,250), pos, False)
                del self.parti
                self.parti = None
                return [pos, rect]
    
    def reset(self):
        self.legIndx = 0
        self.coolDown = 0    # count for attack coolDown

    def hitted(self, damage, pushed, dmgType):
        # decrease health
        true_dmg = round(damage*self.realDmgRate)
        self.health -= true_dmg
        self.msgList.append( [getPos(self,0.5,0.5), str(true_dmg), 60] )
        if self.health <= 0:                # dead。
            self.doom = True
            self.health = 0
            return True
        if pushed>0:   # 向右击退
            self.hitBack = max( pushed-self.weight, 0 )
        elif pushed<0: # 向左击退
            self.hitBack = min( pushed+self.weight, 0 )

    def paint(self, screen):
        # 画阴影
        shadRect = self.rect.copy()
        shadRect.left -= self.shadOffset
        screen.blit(self.shad, shadRect)
        screen.blit( self.leg.image, self.leg.rect )
        screen.blit( self.image, self.rect )
        # 画打击阴影
        if self.hitBack:
            screen.blit( self.shad, self.rect )
    
    def lift(self, dist):                   # 所有monster都应可以响应model主函数的调用而竖直方向上移动。
        self.rect.top += dist
        self.scope_y = (self.scope_y[0]+dist, self.scope_y[1]+dist)
    
    def level(self, dist):
        self.rect.left += dist
        self.scope_x = (self.scope_x[0]+dist, self.scope_x[1]+dist)


# ========================================================================
# --------------------------------- CP 3 ---------------------------------
# ========================================================================
class MistGenerator():
    canvas = None
    canvasRect = None

    def __init__(self, bg_size):
        self.bg_size = bg_size
        self.category = "mist"
        self.mistNum = 4
        # 用两个列表分别存储团状黑雾的中心点坐标、半径和移动速度；光亮物中点坐标和范围。
        self.darks = []
        self.lumis = []      # [ (centerPos, InnerRange), (...) ]
    
    def renew(self, delay, sprites):        
        # 定时检查数量，错开添加以造成错开的效果
        if not delay%240:
            if len(self.darks)<self.mistNum:
                self.generateMist()
        # 更新雾团位置
        for each in self.darks[::-1]:
            rect = each[1]
            if (each[2]<0 and rect.right<=0) or (each[2]>0 and rect.left>=self.bg_size[0]):
                self.darks.remove(each) # 出界可以移除了
            else:
                if delay%2:
                    rect.top += 2
                    rect.left += each[2]
                    each[1] = rect
                else:
                    rect.top -= 2
        # 更新光亮物范围。
        self.lumis.clear()
        for each in sprites:
            if hasattr(each, "lumi") and each.lumi>20:
                ctr = getPos(each, 0.5, 0.5)
                # 营造视野圆圈摇曳效果
                if delay%2:
                    gap = 2
                else:
                    gap = -2
                self.lumis.append( (ctr, each.lumi+gap) )

    def generateMist(self):
        radMax = randint(110,190)
        speed = choice([1,2,3,-1,-2,-3])
        if speed<0: # 从右至左
            core = [self.bg_size[0]+radMax+randint(-10,40), randint(110, self.bg_size[1]-110)]
        else:       # 从左至右
            core = [-radMax+randint(-40,10), randint(110, self.bg_size[1]-110)]
        surf = pygame.Surface( (radMax*2, radMax*2) ).convert_alpha()
        surf.fill((0,0,0,0))
        rect = surf.get_rect()
        rect.left = core[0]-radMax
        rect.top = core[1]-radMax
        alpha = 20  # 最外圈的透明度
        rad = radMax
        for i in range(4):
            pygame.draw.circle( surf, (20,0,10,alpha), (radMax, radMax), rad, 0 )
            rad = max(rad-12, 0)
            alpha = min(alpha+65, 240)  # 最内层透明度上限为240
        self.darks.append( [surf, rect, speed] )
    
    def paint(self, canvas):
        for each in self.darks:
            surf_copy = each[0].copy()   # 复制。对于有lumi覆盖的要加上lumi
            for lumi in self.lumis:
                # 计算光亮点的相对坐标
                lumi_x = lumi[0][0]-each[1].left
                lumi_y = lumi[0][1]-each[1].top
                pygame.draw.circle( surf_copy, (0,0,0,60), (lumi_x,lumi_y), lumi[1], 0 )
                pygame.draw.circle( surf_copy, (0,0,0,0), (lumi_x,lumi_y), lumi[1]-10, 0 )
            canvas.blit(surf_copy, each[1])
        
# -----------------------------------
class Skeleton(Monster):
    imgLib = None
    shadLib = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLib:
            Skeleton.imgLib = {
                "popList": createImgList("image/stg3/pop0.png","image/stg3/pop1.png","image/stg3/pop2.png", 
                    "image/stg3/pop3.png","image/stg3/pop4.png","image/stg3/pop5.png","image/stg3/pop6.png","image/stg3/pop7.png"),
                "iList": createImgList( "image/stg3/skeletonLeft0.png","image/stg3/skeletonLeft1.png",
                    "image/stg3/skeletonLeft2.png","image/stg3/skeletonLeft1.png" ),
                "att": createImgList("image/stg3/attLeft.png")
            }
            Skeleton.shadLib = getShadLib(Skeleton.imgLib)
        
        # calculate its position
        Monster.__init__(self, "skeleton", (255,255,255,240), 3, 1, onlayer, sideGroup, debri=("boneDebri",4))
        self.wallList = []       # 存储本行的所有砖块; # 每次初始化一个新实例时，清空此类的wallList（否则会在上一个实例的基础上再加！）
        posList = []             # 辅助列表，用于暂时存储本行砖块的位置（左边线）
        for aWall in wallGroup:  # 由于spriteGroup不好进行索引/随机选择操作，因此将其中的sprite逐个存入列表中存储
            if not aWall.category == "specialWall":  # 排除特殊砖块上生成，造成空的popping操作
                self.wallList.append(aWall)
                posList.append(aWall.rect.left)
        if len(self.wallList) == 0:
            self.kill()
            return None
        wall = choice(self.wallList)
        leftMax = wall.rect.left
        rightMax = wall.rect.right   # note：此处砖块的右坐标即下一砖块的左坐标
        while True:
            if leftMax in posList:
                leftMax -= blockSize
            else:
                leftMax += blockSize # 将多减的加回来
                break
        while True:
            if rightMax in posList:
                rightMax += blockSize
            else:
                break
        self.scope = (leftMax, rightMax)
        # initialize the sprite
        self.imgIndx = 0
        self.setImg("popList",0)
        self.coolDown = 0
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top
        self.birth = [wall.rect.left+wall.rect.width//2, wall.rect.top]
        if random()<=0.5:
            self.alterSpeed(-3)
        else:
            self.alterSpeed(3)
        self.lumi = 2
        self.popping = True                    # 出生阶段为True

    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        if not (delay % 4): 
            if not self.popping:
                if self.stun_time==0:
                    self.rect.left += self.speed   # pop阶段的最后一张图片和移动阶段的第一张图片大小刚好是相等的，完美对接
                    if (getPos(self,0.75,0)[0] >= self.scope[1] and self.speed > 0) or (getPos(self,0.25,0)[0] <= self.scope[0] and self.speed < 0):
                        self.alterSpeed(-self.speed)
                    if not (delay % 8):
                        # update image
                        tmpPos = getPos(self, 0.5, 1)
                        self.setImg("iList",self.imgIndx)
                        self.mask = pygame.mask.from_surface(self.image)
                        self.rect = self.image.get_rect()
                        self.rect.bottom = tmpPos[1]
                        self.rect.left = tmpPos[0]- self.rect.width//2
                        self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                    if self.coolDown==0:
                        for each in sprites:
                            if ( collide_mask(self, each) ):
                                self.coolDown = 8  # 归在delay整除4的条件下，故实际间隔为8*4 = 32
                    else:
                        self.cratch(sprites)
                        self.coolDown -= 1
            elif self.popping:
                self.setImg("popList",self.imgIndx)
                self.rect = self.image.get_rect()
                self.rect.bottom = self.birth[1]
                self.rect.left = self.birth[0]- self.rect.width//2
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["popList"])
                if self.imgIndx == 0:
                    self.popping = False      # 若imgIndx 第一次变为零，则表示完成了一次pop的过程

    def cratch(self, sprites):
        if (self.coolDown >= 4):
            self.setImg("att")
            if ( self.coolDown == 5 ):
                cldList( self, sprites )
    
    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.coolDown = 0
    
    def lift(self, dist):
        self.rect.bottom += dist
        self.birth[1] += dist

    def level(self, dist):
        self.rect.left += dist
        self.birth[0] += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

# -----------------------------------
class Dead(Monster):
    imgLibMale = None
    imgLibFemale = None
    shadLibMale = None
    shadLibFemale = None
    snd = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLibMale:
            Dead.imgLibMale = {
                "iList": createImgList( "image/stg3/deadMale0.png", "image/stg3/deadMale1.png", 
                    "image/stg3/deadMale2.png", "image/stg3/deadMale1.png"),
                "att": createImgList("image/stg3/deadMaleVomit.png")
            }
            Dead.imgLibFemale = {
                "iList": createImgList( "image/stg3/deadFemale0.png", "image/stg3/deadFemale1.png", 
                    "image/stg3/deadFemale2.png", "image/stg3/deadFemale1.png"),
                "att": createImgList("image/stg3/deadFemaleVomit.png")
            }
            Dead.shadLibMale = getShadLib(Dead.imgLibMale)
            Dead.shadLibFemale = getShadLib(Dead.imgLibFemale)
            Dead.snd = pygame.mixer.Sound("audio/vomiSplash.wav")
        
        # calculate its position
        Monster.__init__(self, "dead", (10,10,10,240), 0, 2, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        self.onlayer = int(onlayer)
        # initialize the sprite
        if random()<0.5:
            self.imgLib = self.imgLibMale
            self.shadLib = self.shadLibMale
        else:
            self.imgLib = self.imgLibFemale
            self.shadLib = self.shadLibFemale
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left + (wall.rect.width-self.rect.width) // 2
        self.rect.bottom = wall.rect.top
        self.lumi = 3
        if random()<=0.5:
            self.alterSpeed(-2)
        else:
            self.alterSpeed(2)

    def move(self, delay, sprites, canvas):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        if not (delay % 6) and not self.voming: 
            if self.stun_time==0:
                self.rect.left += self.speed
                if (self.rect.right >= self.scope[1] and self.speed > 0) or (self.rect.left <= self.scope[0] and self.speed < 0):
                    self.alterSpeed(-self.speed)
                if not (delay % 12):
                    self.setImg("iList",self.imgIndx)
                    self.mask = pygame.mask.from_surface(self.image)  # 更新rect，使得与hero重合的判断更加精确
                    self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                if random()<0.04:
                    for hero in sprites:
                        if -2 < hero.onlayer-self.onlayer+1 < 2:
                            self.snd.play(0)
                            break
                    self.voming = 54
                # Check Hero and Turn.
                self.detectHero(sprites)
        if (self.voming > 0):
            self.setImg("att")
            self.voming -= 1
            if (self.voming < 48) and (self.voming%2):  # 警告
                # 每2次刷新均吐出1个气团
                spdX = 7-self.voming//8
                if self.speed <= 0:
                    spd = [ -spdX, 0 ]
                    startX = 0.2
                elif self.speed > 0:
                    spd = [ spdX, 0 ]
                    startX = 0.8
                canvas.addAirAtoms(self, 1, getPos(self, startX, 0.5), spd, 
                                    sprites, "corrosive", btLine=self.rect.bottom)

    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.coolDown = 0
        self.voming = 0

    def reportHit(self, hero):
        if hasattr(hero,"infected") and hero.infected<0:
            hero.infect()
        hero.hitted( self.damage, 0, self.dmgType )

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

# -----------------------------------
class Ghost(Monster):
    imgLib = None
    shadLib = None

    def __init__(self, XRange, y, onlayer):
        if not self.imgLib:
            Ghost.imgLib = {
                "iList": createImgList("image/stg3/ghost0.png","image/stg3/ghost1.png"),
                "extraList": createImgList("image/stg3/ghost_extra0.png","image/stg3/ghost_extra1.png")
            }
            Ghost.shadLib = getShadLib( Ghost.imgLib )
            Ghost.snd = pygame.mixer.Sound("audio/ghost_resurrect.wav")

        # initialize the sprite
        Monster.__init__(self, "ghost", (255,120,190,120), 6, 0, onlayer)
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.rect.left = randint( XRange[0], XRange[1] )
        self.rect.top = y
        self.alterSpeed(-1)
        self.upDown = 1
        self.nxt = [0,0]
        # Parameters about second life
        self.extraLife = 1
        self.cnt = 0        # 被打碎时的复生实时倒计时
        self.returnTime = 50# 倒计时上限

    def move(self, delay, sprites, spurtCanvas):
        self.checkHitBack()
        self.count_stun()
        if self.cnt==0:
            if not (delay % 8 ):
                # 变换图片
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                self.setImg("iList",self.imgIndx)
                # 飘动
                self.rect.top += self.upDown
                self.upDown = -self.upDown
                # 更新目标位置
                if not self.tgt:
                    self.tgt = choice(sprites)
                    self.nxt = getPos(self.tgt, 0.5, 0.5)
                else:
                    self.nxt = getPos(self.tgt, 0.5, 0.5)
                    self.direction = "left" if ( self.nxt[0] < self.rect.left + self.rect.width/2 ) else "right"
                    if self.tgt.health<=0:
                        self.tgt = None
            if self.stun_time==0:
                # charging motion
                if not (delay % 4):
                    self.shift( self.nxt[0], self.nxt[1] )
                if (self.coolDown == 0):
                    for each in sprites:
                        if collide_mask(self, each):
                            self.coolDown = 42
                elif self.coolDown > 0:
                    self.coolDown -= 1
                    if self.coolDown >= 32:
                        #self.setImg("att")
                        if self.direction=="left":
                            self.push = self.pushList[0]
                        else:
                            self.push = self.pushList[1]
                        if self.coolDown == 34:
                            cldList( self, sprites )
        else:
            if self.cnt==self.returnTime:
                spurtCanvas.addSpatters(7, [3,6,9], [20,24,28], self.bldColor, getPos(self,0.5,0.48), falling=False, back=True)
                spurtCanvas.addSpatters(7, [3,6,9], [20,24,28], (255,180,240), getPos(self,0.5,0.52), falling=False, back=True)
            self.cnt -= 1
            if self.cnt==0:
                return "rejoin"
            else:
                return "out"

    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.coolDown = 0   # count for attack coolDown
        self.tgt = None

    def shift(self, final_x, final_y):
        spd = 6
        dist = 0
        x = self.rect.left + self.rect.width/2
        y = self.rect.top + self.rect.height/2
        if (x == final_x) and (y == final_y):
            return True
        if (x < final_x):
            dist = min( math.ceil( (final_x - x)/spd ), 5 )
            self.rect.left += dist
        elif (x > final_x):
            dist = min( math.ceil( (x - final_x)/spd ), 5 )
            self.rect.left -= dist
        if (y < final_y):
            dist = min( math.ceil( (final_y - y)/spd ), 4 )
            self.rect.top += dist
        elif (y > final_y):
            dist = min( math.ceil( (y - final_y)/spd ), 4 )
            self.rect.top -= dist
    
    def hitted(self, damage, pushed, dmgType):
        # decrease health
        true_dmg = round(damage*self.realDmgRate)
        self.health -= true_dmg
        self.msgList.append( [getPos(self,0.5,0.5), str(true_dmg), 60] )
        if self.health <= 0:        # dead。但是有可能复活
            if self.extraLife>0:
                self.snd.play(0)
                self.health = self.full
                self.extraLife -= 1
                self.cnt = self.returnTime       # 复活倒计时置为returnTime
                self.imgLib = {
                    "iList": Ghost.imgLib["extraList"]
                }
                self.setImg("iList",0)
            else:
                self.health = 0
                self.kill()
                #self.snd.stop()
                return True
        if pushed>0:   # 向右击退
            self.hitBack = max( pushed-self.weight, 0 )
        elif pushed<0: # 向左击退
            self.hitBack = min( pushed+self.weight, 0 )
    
    def paint(self, surface):
        if self.cnt==0:
            # ghost没有阴影！
            surface.blit( self.image, self.rect )
            # 画打击阴影
            if self.hitBack:
                surface.blit( self.shad, self.rect )
    
    def level(self, dist):
        self.rect.left += dist
        self.nxt[0] += dist
    
    def lift(self, dist):
        self.rect.top += dist
        self.nxt[1] += dist
    
# Boss ------------------------------
class Vampire(Boss):
    sycthe = None
    
    def __init__(self, groupList, onlayer, boundaries, font):
        # initialize the sprite
        Boss.__init__(self, font, "Vampire", (10,30,10,240), 8, 1, onlayer, sideGroup=groupList["0"])
        self.boundaries = boundaries
        self.initLayer(groupList)
        # initialize the sprite
        self.imgLib = {
            "iList": createImgList( "image/stg3/Vampire0.png", "image/stg3/Vampire1.png" ),
            "attList": createImgList( "image/stg3/VampireAtt0.png", "image/stg3/VampireAtt1.png", "image/stg3/VampireAtt2.png" ),
            "summon": createImgList( "image/stg3/VampireSummon.png" )
        }
        self.shadLib = getShadLib(self.imgLib)
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.rect.left = self.initPos[0]-self.rect.width//2  # 位于砖块居中
        self.rect.bottom = self.initPos[1]
        # Define scythe. ----------------------------------------
        self.scytheR = { "left":(0.15,0.7, 0), "right":(0.85,0.7, 0) }
        self.scytheAttR = { "left":[ (0.6,0.5, 0), (0.25, 0.69, 1), (0.4,0.87, 1) ], "right":[ (0.4,0.5, 0), (0.75, 0.69, 1), (0.6,0.87, 1) ] }
        self.scytheImg = createImgList( "image/stg3/scythe.png" )
        self.scytheAttImg = createImgList( "image/stg3/scytheAtt0.png", "image/stg3/scytheAtt1.png", "image/stg3/scytheAtt2.png" )
        self.scythe = Ajunction( self.scytheImg["left"][0], getPos(self, self.scytheR["left"][0], self.scytheR["left"][1]) )
        # ----------- other attributes -------------------------
        self.snd = pygame.mixer.Sound("audio/vampireAtt.wav")
        self.laughSnd = pygame.mixer.Sound("audio/vampire_laugh.wav")
        self.alterSpeed( choice([-1,0,1]) )
        self.status = "wandering"          # wandering表示闲逛的状态，alarming表示发现英雄的状态
        self.wpPos = (0, 0, 0)
        self.flying = False
        self.lumi = 4
        self.upDown = 1
        self.summonCD = 330               # 召唤冷却
            
    # 这个move()函数是供外界调动的接口，这里仅起根据传入的英雄参数判断状态的作用。判断完成后，修改自身的状态，然后执行相应的函数。
    def move(self, delay, sprites, groupList, canvas):
        self.checkHitBack(obstacle=True)
        self._tipPosition(canvas)
        self.count_stun()
        
        # Effect
        if not delay%2:
            # 身体紫光
            canvas.addSmoke( 1, (2,4,5), 4, (120,10,110,180), getPos(self,0.5,1), 20, speed=[-self.speed,-1] )
            # 眼睛紫光
            for i in (0.4,0.6):
                canvas.addSmoke( 1, (1,2), 6, (190,40,170,180), getPos(self,i,0.38), 5, speed=[0,0] )
        if self.stun_time==0:
            # change layer
            if not (delay%20) and not self.flying and self.status=="wandering" and random()<0.1:
                self.flying = True
                hero = choice( sprites )
                # 向hero所在的层数进逼。由于hero能在的层数一定是合法的，故这里不需要检测层数的合法性（不需边界测试）
                if self.onlayer > 1 and self.onlayer > hero.onlayer-1:   # 注意，这里由于层数体系不一样，要检查self.layer为1时不能减为-1（那就成了sideWall！）
                    self.onlayer -= 2
                elif self.onlayer < hero.onlayer-1:
                    self.onlayer += 2
                self.initLayer(groupList)           # 计算其在新一行的水平scope
        # 优先处理 flying $$$$
        if self.flying:
            self.rect.bottom += ( (self.initPos[1]-getPos(self, 0.5, 1)[1]) // 20 )
            self.rect.left += ( (self.initPos[0]-getPos(self, 0.5, 1)[0]) // 20 )
            #以竖直方向为标准，若已抵达(等于或略高于)目标行，则将flying标记为False
            if 0<= (self.initPos[1]-self.rect.bottom) < 20:
                self.rect.bottom = self.initPos[1]
                self.flying = False
        else:
            if not (delay % 20):
                self.rect.top += self.upDown
                self.upDown = - self.upDown
            if self.stun_time==0:
                for hero in sprites:
                    # 如果有英雄在同一层，则将速度改为朝英雄方向。(两套体系：英雄的层数为偶数，而怪物用的层数都是奇数)
                    if ( (hero.onlayer-1)==self.onlayer and abs( getPos(hero,0.5,0.5)[0]-getPos(self,0.5,0.5)[0] )<=360 ) or self.coolDown>0:
                        self.status = "alarming"
                        self.tgt = hero
                        break     # 这里碰到第一个英雄符合条件就退出了。如果两个英雄同时在一层中，P1总是会被针对，而P2永远不会被选中为目标。问题留着以后修正。
                    else:
                        self.status = "wandering"
                if self.status == "wandering":
                    # 游荡状态，删除残影
                    if self.rectList:
                        self.rectList.pop(0)
                    # wander 部分
                    if (self.speed):                        # speed!=0，在运动。
                        self.rect.left += self.speed
                        if (getPos(self, 0.7, 1)[0] >= self.scope[1] and self.speed > 0) or (getPos(self, 0.3, 1)[0] <= self.scope[0] and self.speed < 0):
                            self.alterSpeed(-self.speed)
                        if not delay % 20 and random()<0.08:# 随机进入休息状态。
                            self.alterSpeed(0)
                    elif not delay % 20 and random()<0.08:  # 否则，在休息。此时若随机数满足条件，进入巡逻状态
                        self.alterSpeed( choice( [1,-1] ) )
                    # wander时还会召唤小型生物。
                    self.summonCD -= 1
                    if self.summonCD <= 32:
                        if self.summonCD == 32:
                            self.laughSnd.play(0)
                        trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]
                        self.setImg("summon")
                        self.rect = self.image.get_rect()
                        self.rect.left = trPos[0]-self.rect.width//2
                        self.rect.bottom = trPos[1]
                        if self.summonCD == 0:
                            self.summonCD = 420
                            babe = choice( ["skeleton", "dead", "ghost"] )
                            pos = getPos(self, choice( [0.1,0.9] ), 0)
                            return (babe,pos)
                        return
                elif self.status == "alarming":
                    if not self.coolDown:
                        if getPos( self.tgt, 0.5, 0.5 )[0]>getPos( self, 0.5, 0.5 )[0]:
                            self.alterSpeed(1)
                        else:
                            self.alterSpeed(-1)
                    #attack部分
                    self.rectList.append(self.rect.copy())
                    if len(self.rectList)>6:
                        self.rectList.pop(0)
                    self.rect.left += self.speed*8
                    if self.coolDown==0:
                        for each in sprites:
                            if abs(getPos(self, 0.5, 0.5)[0]-getPos(each, 0.5, 0.5)[0])<60:
                                self.snd.play(0)    # 攻击英雄，咆哮
                                self.speed = 0
                                self.coolDown = 44
                    else:
                        self.coolDown -= 1
            
            # check img
            if self.coolDown <= 0:
                self.wpPos = self.scytheR[self.direction]
                if not (delay % 14 ):
                    self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                self.setImg("iList",self.imgIndx)
                self.scythe.updateImg( self.scytheImg[self.direction][0] )
                self.scythe.updatePos( getPos(self, self.wpPos[0], self.wpPos[1]) )
            else:   # 被stun reset后，coolDown=0，这一块（攻击）不会被执行
                if self.coolDown >= 16:
                    attIndx = 0
                elif self.coolDown >= 8:
                    attIndx = 1
                    for each in sprites:
                        if collide_mask(self.scythe, each):
                            each.hitted( self.damage, self.push, self.dmgType )
                            self.recover( round(self.damage*0.5) )
                else:
                    attIndx = 2
                self.wpPos = self.scytheAttR[self.direction][attIndx]
                self.setImg("attList",attIndx)
                self.scythe.updateImg( self.scytheAttImg[self.direction][attIndx] )
                self.scythe.updatePos( getPos(self, self.wpPos[0], self.wpPos[1]) )
            # checkImg部分
            trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]
            self.rect = self.image.get_rect()
            self.rect.left = trPos[0]-self.rect.width//2
            self.rect.bottom = trPos[1]

    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.tgt = None         # 指示要攻击的英雄
        self.coolDown = 0
        self.rectList = []      # 残影列表

    # 此函数用于确定新一行中的位置及scope
    def initLayer(self, groupList):
        self.wallList = []          # 存储本行的所有砖块; # 每次初始化一个新实例时，清空此类的wallList（否则会在上一个实例的基础上再加！）
        posList = []                # 辅助列表，用于暂时存储本行砖块的位置（左边线）
        for aWall in groupList[str(self.onlayer)]:  # 由于spriteGroup不好进行索引/随机选择操作，因此将其中的sprite逐个存入列表中存储
            self.wallList.append(aWall)
            posList.append(aWall.rect.left)
        if len(self.wallList)==0:
            # dead
            #self.moanSnd.play(0)
            self.kill()
            return
        if self.activated:          # 找新层过程的调用，找最近的砖块。
            dist = float("inf")
            for each in self.wallList:
                newDist = abs( getPos(self,0.5,0.5)[0]-getPos(each,0.5,0.5)[0] )
                if newDist < dist:
                    dist = newDist
                    wall = each
        else:                       # 初始化过程的调用
            wall = choice(self.wallList)
        self.initPos = getPos(wall, 0.5, -0.1)   # 新点，居中，漂浮
        leftMax = wall.rect.left
        rightMax = wall.rect.right  # note：此处砖块的右坐标即下一砖块的左坐标
        while True:
            if leftMax in posList: # warmachine比较宽，可以占两格行进
                leftMax -= wall.rect.width
            else:
                leftMax += wall.rect.width  # 将多减的加回来
                break
        while True:
            if rightMax in posList:
                rightMax += wall.rect.width
            else:
                break
        self.scope = (leftMax, rightMax)
        return wall

    def lift(self, dist):
        self.rect.bottom += dist
        self.initPos[1] += dist

    def level(self, dist):
        self.rect.left += dist
        self.initPos[0] += dist
        self.boundaries = (self.boundaries[0]+dist, self.boundaries[1]+dist)

    # 鉴于本对象的构造非常复杂，因此提供一个专门的绘制接口。给此函数传递一个surface参数，即可在该surface上绘制（blit）完整的本对象
    def paint(self, screen):
        # 画残影
        for rect in self.rectList:
            screen.blit(self.shad, rect)
        # 画阴影
        shadRect = self.rect.copy()
        shadRect.left -= self.shadOffset
        screen.blit(self.shad, shadRect)
        #按层级顺序画weapon和self
        if self.wpPos[2]==0:
            screen.blit( self.scythe.image, self.scythe.rect )
            screen.blit( self.image, self.rect )
        elif self.wpPos[2]==1:
            screen.blit( self.image, self.rect )
            screen.blit( self.scythe.image, self.scythe.rect )
        # 画打击阴影
        if self.hitBack:
            screen.blit( self.shad, self.rect )


# ========================================================================
# --------------------------------- CP 4 ---------------------------------
# ========================================================================
class Snake(Monster): 
    imgLib = None
    shadLib = None

    def __init__(self, wallGroup, sideGroup, onlayer):
        if not self.imgLib:
            Snake.imgLib = {
                "iList": createImgList("image/stg4/snake0.png","image/stg4/snake1.png"),
                "dash": createImgList("image/stg4/snakeDash0.png", "image/stg4/snakeDash1.png")
            }
            Snake.shadLib = getShadLib(Snake.imgLib)
        
        # calculate its position
        Monster.__init__(self, "snake", (250,160,120), 4, 1, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top
        self.alterSpeed( choice([-1,1]) )

    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()

        self.tgt = self.detectHero(sprites)
        # move
        if not self.tgt:
            if self.stun_time==0:
                self.rect.left += self.speed
                if (getPos(self,0.75,0)[0]>=self.scope[1] and self.speed>0) or (getPos(self,0.25,0)[0]<=self.scope[0] and self.speed<0):
                    self.alterSpeed( -self.speed )
            if not (delay % 10 ):
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                self.setImg("iList",self.imgIndx)
                self.fitImg()
        else:
            if self.stun_time==0:
                self.rect.left += self.speed*3
                # Attack
                if ( self.coolDown==0 ):
                    for each in sprites:
                        if collide_mask(self, each):
                            self.coolDown = 36
                if (self.coolDown > 0):
                    self.coolDown -= 1
                    if ( self.coolDown == 20 ):
                        cldList( self, sprites )
            if self.tgt.health<=0:
                self.tgt = None
                return
            if not (delay % 6 ):
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                self.setImg("dash",self.imgIndx)
                self.fitImg()
    
    def reset(self):
        self.imgIndx = 0
        self.attIndx = 0
        self.setImg("iList",0)
        self.coolDown = 0
        self.tgt = None

    def fitImg(self):
        trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]   # 为保证图片位置正确，临时存储之前的位置信息
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = trPos[0]-self.rect.width//2
        self.rect.bottom = trPos[1]

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

# -----------------------------------
class Slime(Monster):  
    imgLib = None
    shadLib = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLib:
            Slime.imgLib = {
                "iList": createImgList("image/stg4/slime0.png","image/stg4/slime1.png","image/stg4/slime2.png",
                    "image/stg4/slime3.png","image/stg4/slime4.png","image/stg4/slime5.png", "image/stg4/slime6.png")
            }
            Slime.shadLib = getShadLib(Slime.imgLib)

        # calculate its position
        Monster.__init__(self, "slime", (0,255,0,240), 4, 1, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.imgIndx = 0
        self.setImg("iList",0)
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top
        self.alterSpeed( choice( [-1, 1] ) )
        self.rise = (0,-7,-13,-18,-13,-7,0)
        self.newSlime = None
        self.splitCnt = 3   # 指示本slime仍可分裂的次数。分裂出的slime也获得-1次的cnt。

    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        if self.stun_time==0:
            self.rect.left += self.speed
            if (getPos(self,0.75,0)[0] >= self.scope[1] and self.speed > 0) or (getPos(self,0.25,0)[0] <= self.scope[0] and self.speed < 0):
                self.alterSpeed(-self.speed)
            # slime应该也能做出反应，但比较迟钝
            if not delay % 60:
                self.detectHero(sprites)
            if ( self.coolDown==0 ):
                for each in sprites:
                    if collide_mask(self, each):
                        self.coolDown = 30
            if (self.coolDown > 0):
                self.coolDown -= 1
                if ( self.coolDown == 20 ):
                    cldList( self, sprites )
        
        if not (delay % 5 ):
            trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom-self.rise[self.imgIndx] ]  # 为保证图片位置正确，临时存储之前的位置信息
            self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
            self.setImg("iList",self.imgIndx)
            self.mask = pygame.mask.from_surface(self.image)
            self.rect = self.image.get_rect()
            self.rect.left = trPos[0]-self.rect.width//2
            self.rect.bottom = trPos[1] + self.rise[self.imgIndx]
        # If there is a newly generated slime, return it.
        if (self.newSlime):
            newS = self.newSlime
            self.newSlime = None
            return newS
        
    def reset(self):
        self.coolDown = 0

    def hitted(self, damage, pushed, dmgType):
        if dmgType == "corrosive":
            damage //= 2
        if pushed>0:   # 向右击退
            self.hitBack = max( pushed-self.weight, 0 )
        elif pushed<0: # 向左击退
            self.hitBack = min( pushed+self.weight, 0 )
        true_dmg = round(damage*self.realDmgRate)
        self.health -= true_dmg
        self.msgList.append( [getPos(self,0.5,0.5), str(true_dmg), 60] )
        if self.health <= 0:   # dead
            self.health = 0
            self.kill()
            return True
        else:                  # hitted but alive, check whether to split another slime.
            if ( ( pushed>0 and self.speed<0 ) or ( pushed<0 and self.speed>0 ) ) and self.splitCnt>0:
                self.splitCnt -= 1
                slime = Slime( self.wallList, self.obstacle, 1, self.onlayer )  # 前两项参数都是不需要的，但为了完整执行init函数，第一项参数传入，第二项设为1.
                # 奖励置为0
                slime.coin = 0
                slime.splitCnt = self.splitCnt
                # Set the properties of the generated slime.
                slime.scope = self.scope  
                slime.imgIndx = self.imgIndx  # 图像相同
                slime.alterSpeed(-self.speed) # 速度相反
                slime.setImg("iList",slime.imgIndx)
                slime.rect = slime.image.get_rect()
                slime.rect.left = getPos(self, 0.5, 0.5)[0] - slime.rect.width//2
                slime.rect.bottom = self.rect.bottom  # 位置相同
                self.newSlime = slime         # 挂到本对象的newSlime变量上，等待下一次刷新调用move的时候上报给model。

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

# -----------------------------------
class Nest(Monster):
    imgLib = None
    shadLib = None

    def __init__(self, wallGroup, onlayer):
        if not self.imgLib:
            Nest.imgLib = {
                "eggList": createImgList("image/stg4/nest0.png","image/stg4/nest1.png")
            }
            Nest.shadLib = getShadLib(Nest.imgLib)

        # calculate its position
        Monster.__init__(self, "nest", (255,255,80,240), 0, 0, onlayer)
        self.wallList = []       # 存储本行的所有砖块; # 每次初始化一个新实例时，清空此类的wallList（否则会在上一个实例的基础上再加！）
        posList = []             # 辅助列表，用于暂时存储本行砖块的位置（左边线）
        for aWall in wallGroup:  # 由于spriteGroup不好进行索引/随机选择操作，因此将其中的sprite逐个存入列表中存储
            self.wallList.append(aWall)
            posList.append(aWall.rect.left)
        wall = choice(self.wallList)
        # initialize the sprite
        self.imgIndx = 0
        self.setImg("eggList",0)
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.top = wall.rect.bottom-8  # link more tight with the block (block bottom is not even)

    def move(self, delay, mons):
        self.count_stun()
        if self.health > 0:
            if not (delay % 24 ):
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["eggList"]["left"])
                self.setImg("eggList",self.imgIndx)
                if random() < 0.1:
                    worm = Worm( self.rect.left+self.rect.width//2, self.rect.bottom, self.onlayer )
                    return [worm]
        else:
            pos1 = getPos(self, 0.3, 0.3)
            worm1 = Worm( pos1[0], pos1[1], self.onlayer )
            pos2 = getPos(self, 0.5, 0.6)
            worm2 = Worm( pos2[0], pos2[1], self.onlayer )
            pos3 = getPos(self, 0.7, 0.3)
            worm3 = Worm( pos3[0], pos3[1], self.onlayer )
            self.kill()
            return [ worm1, worm2, worm3 ]

    def stun(self, duration):
        pass
    
    def hitted(self, damage, pushed, dmgType):
        true_dmg = round(damage*self.realDmgRate)
        self.health -= true_dmg
        self.msgList.append( [getPos(self,0.5,0.5), str(true_dmg), 60] )
        if self.health <= 0:
            self.health = 0
            return True

class Worm(Monster):  
    imgLib = None
    shadLib = None

    def __init__(self, x, y, onlayer):  
        if not self.imgLib:
            Worm.imgLib = {
                "iList": createImgList("image/stg4/worm0.png","image/stg4/worm1.png", 
                    "image/stg4/worm2.png","image/stg4/worm3.png","image/stg4/worm4.png")
            }
            Worm.shadLib = getShadLib(Worm.imgLib)
        
        Monster.__init__(self, "worm", (255,255,10,240), 1, 0, onlayer-2)# 由于掉落下来一定要减一层，所以传入onlayer-2。
        # initialize the sprite
        self.imgIndx = 0
        self.attIndx = 0
        self.setImg("iList",0)
        self.mask = pygame.mask.from_surface( self.image )
        self.rect = self.image.get_rect()
        self.rect.left = x-self.rect.width//2
        self.rect.top = y
        if random()<= 0.5:   # 随即决定向左或向右
            self.alterSpeed(-1)
        else:
            self.alterSpeed(1)
        #self.aground = False
        self.doom = 0
        self.lifeSpan = 300

    def move(self, delay, lineWall, keyLine, sideWall, sprites, canvas, GRAVITY):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        # 无论health和lifespan是否有，都要检查下落
        self.fall(lineWall, keyLine, GRAVITY)
        # 若健康的话，检查与英雄的碰撞
        if (self.health>0) and (self.lifeSpan > 0):
            self.lifeSpan -= 1
            # 进行水平运动
            if not (delay % 5):
                if self.stun_time==0:
                    self.rect.left += self.speed
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                self.setImg("iList",self.imgIndx)
                if ( pygame.sprite.spritecollide(self, sideWall, False, collide_mask) ):
                    self.alterSpeed(-self.speed)
            for each in sprites:
                if ( collide_mask(self, each) ):
                    self.health = 0
        else:
            self.doom += 1
            if self.doom == 8:
                self.kill()
            elif self.doom == 7:
                cldList( self, sprites )    # 检查溅射到英雄，造成伤害
            elif self.doom >= 1:
                if self.doom == 1:
                    canvas.addExplosion( getPos(self, 0.5, 0.5), 
                        14, 8, waveColor=self.bldColor, spatColor=self.bldColor, dotD=(8,10,12), smoke=False 
                    )
                self.image = load("image/stg4/worm_boom.png")

    def fall(self, lineWall, keyLine, GRAVITY):
        self.rect.bottom += (GRAVITY-1)
        while ( pygame.sprite.spritecollide(self, lineWall, False, collide_mask) ):      # 如果和参数中的物体重合，则尝试纵坐标-1
            self.rect.bottom -= 1
            #if not ( pygame.sprite.spritecollide(self, lineWall, False, collide_mask) ): # 循环-1，直到不再和任何物体重合为止，进入这个if语句跳出循环
            #    self.aground = True
        if self.rect.top >= keyLine:
            self.onlayer = max(self.onlayer-2, -1)
        
    def hitted(self, damage, pushed, dmgType):
        true_dmg = round(damage*self.realDmgRate)
        self.health -= true_dmg
        self.msgList.append( [getPos(self,0.5,0.5), str(true_dmg), 60] )
        if self.health <= 0:
            self.health = 0
            return True    # dead

    def drawHealth(self, surface):
        pass

# -----------------------------------
class Fly(Monster):  
    imgLib = None
    shadLib = None

    def __init__(self, XRange, y, onlayer):
        if not self.imgLib:
            Fly.imgLib = {
                "iList": createImgList("image/stg4/flyLeft0.png","image/stg4/flyLeft1.png", 
                    "image/stg4/flyLeft0.png","image/stg4/flyLeft2.png"),
                "att": createImgList("image/stg4/flyAtt.png")
            }
            Fly.shadLib = getShadLib(Fly.imgLib)
            Fly.snd = pygame.mixer.Sound("audio/flapper.wav")

        # initialize the sprite
        Monster.__init__(self, "fly", (0,255,10,240), 6, 1, onlayer)
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.leftBd = XRange[0]
        self.rightBd = XRange[1]
        self.rect.left = randint( XRange[0], XRange[1] )
        self.rect.top = y
        self.alterSpeed(-1)

    def move(self, delay, sprites):
        self.checkHitBack()
        self.count_stun()
        if not (delay % 4 ):
            self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
            self.setImg("iList",self.imgIndx)
        # find new position
        if self.cnt == 0:
            self.cnt = 60
            self.nxt = [ randint(self.leftBd, self.rightBd), randint(20, 580) ]  # randomize a new position
            self.direction = "left" if ( self.nxt[0] < self.rect.left + self.rect.width/2 ) else "right"
        if self.stun_time==0:
            # charging motion
            if not (delay % 3):
                self.shift( self.nxt[0], self.nxt[1] )
                self.cnt -= 1
                if random()<0.02:
                    self.snd.play(0)
            if (self.coolDown == 0):
                for each in sprites:
                    if collide_mask(self, each):
                        self.coolDown = 42
            elif self.coolDown > 0:
                self.coolDown -= 1
                if self.coolDown >= 32:
                    self.setImg("att")
                    if self.direction=="left":
                        self.push = self.pushList[0]
                    else:
                        self.push = self.pushList[1]
                    if self.coolDown == 34:
                        cldList( self, sprites )

    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.cnt = 0       # count for the loop of shift position
        self.coolDown = 0    # count for attack coolDown
        self.nxt = [0, 0]

    def shift(self, final_x, final_y):
        maxSpan = 8
        spd = 4
        dist = 0
        x = self.rect.left + self.rect.width/2
        y = self.rect.top + self.rect.height/2
        if (x == final_x) or (y == final_y):
            return True
        if (x < final_x):
            dist = min( math.ceil( (final_x - x)/spd ), 5 )
            self.rect.left += dist
        elif (x > final_x):
            dist = min( math.ceil( (x - final_x)/spd ), 5 )
            self.rect.left -= dist
        if (y < final_y):
            dist = min( math.ceil( (final_y - y)/spd ), 4 )
            self.rect.top += dist
        elif (y > final_y):
            dist = min( math.ceil( (y - final_y)/spd ), 4 )
            self.rect.top -= dist
    
    def erase(self):
        self.snd.stop()
        self.kill()
        del self

    def level(self, dist):
        self.rect.left += dist
        self.nxt[0] += dist
        self.leftBd += dist
        self.rightBd += dist
    
    def lift(self, dist):
        self.rect.top += dist
        self.nxt[1] += dist

# Boss ------------------------------
class MutatedFungus(Boss):
    def __init__(self, xRange, y, onlayer, font):
        # initialize the sprite
        Boss.__init__(self, font, "MutatedFungus", (255,190,140,240), 1, 1, onlayer, shadOffset=12)
        self.xRange = xRange
        # ----- body part (the core of the Python) ------
        self.imgLib = {
            "body": createImgList("image/stg4/fungus.png")
        }
        self.shadLib = getShadLib(self.imgLib)
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.rect.left = randint(xRange[0], xRange[1])
        self.rect.bottom = y
        # ------------- tentacle part ----------------
        self.tentLeft = [ pygame.image.load("image/stg4/tentacle0.png").convert_alpha(), pygame.image.load("image/stg4/tentacle1.png").convert_alpha() ]
        self.tentRight = [ pygame.transform.flip(self.tentLeft[0], True, False), pygame.transform.flip(self.tentLeft[1], True, False) ]
        self.tentR = { "left":[ (0.5,1.1), (0.5,1.1) ], "right":[ (0.5,1.1), (0.5,1.1) ] }
        self.tent = Ajunction( self.tentLeft[0], getPos(self, self.tentR[self.direction][0][0], self.tentR[self.direction][0][1]) )
        # ----------- other attributes -------------------------
        #self.fireSnd = pygame.mixer.Sound("audio/MachineGrenade.wav")
        #self.moanSnd = pygame.mixer.Sound("audio/MachineCollapse.wav")
        self.cnt = 1020      # count for the loop of shift position
        self.alterSpeed(0)
        self.upDown = 1
        self.releaseInter = 60  # 释放孢子的间隔，可能随着体力降低而加快

    def move(self, delay, heroes):
        self.checkHitBack()
        self._tipPosition(self.spurtCanvas)
        self.count_stun()

        if not self.cnt%4:
            self.spurtCanvas.addSmoke(2, (3,5,7), 5, (200,255,180,250), getPos(self,0.5,random()), 60)
            if self.stun_time==0:
                self.shift( self.nxt[0], self.nxt[1] )
            # 上下摆动
            self.rect.top += self.upDown
            self.upDown = - self.upDown
        # count down for rage actions.
        self.cnt -= 1
        if self.cnt<=0:
            self.cnt = 1420
        else:
            if not self.cnt%60:
                self.nxt = ( randint( self.xRange[0], self.xRange[1] ), randint(40,520) )   # randomize a new position
                self.direction = "left" if ( self.nxt[0] < getPos(self, 0.5, 0.5)[0] ) else "right"
        if not ( delay % 8 ):
            # 更新各组件的图像
            self.setImg("body", self.imgIndx)
            self.mask = pygame.mask.from_surface(self.image)
            self.tentIndx = (self.tentIndx+1) % len(self.tentLeft)
            if self.direction == "left":
                self.tent.updateImg( self.tentLeft[self.tentIndx] )
            elif self.direction == "right":
                self.tent.updateImg( self.tentRight[self.tentIndx] )
        # 不管是什么时候，都应该及时更新ajunction的位置（还会有英雄击退）
        self.tent.updatePos( getPos(self, self.tentR[self.direction][self.tentIndx][0], self.tentR[self.direction][self.tentIndx][1]) )
        # Deal damage with its tentacle.
        if not delay % DMG_FREQ:
            for each in heroes:
                if collide_mask( self.tent, each ):
                    each.hitted( self.damage, self.push, self.dmgType )
        # release miniFungus.
        if not delay%self.releaseInter:
            # Determine tgt and distance
            aim = getPos( choice(heroes), 0.5,0.4 )
            myPos = getPos(self,0.5,0.4)
            delta = [ aim[0]-myPos[0], aim[1]-myPos[1] ]
            spd = [0,0]
            for i in range(2):
                if delta[i]>80:
                    spd[i] = 1
                elif delta[i]<-80:
                    spd[i] = -1
                else:
                    spd[i] = 0
            miniFungus = MiniFungus( [self.rect.left+60,self.rect.right-60], myPos[1], spd )
            return miniFungus

    def reset(self):
        self.imgIndx = 0
        self.setImg("body")
        self.tentIndx = 0
        self.coolDown = 0    # count for attack coolDown
        self.nxt = (0, 0)

    def paint(self, screen):
        # draw shadow
        shadRect = self.rect.copy()
        shadRect.left -= self.shadOffset
        screen.blit(self.shad, shadRect)
        # draw self
        screen.blit( self.tent.image, self.tent.rect )
        screen.blit( self.image, self.rect )
        # Hit highlight
        if self.hitBack:
            screen.blit( self.shad, self.rect )
    
    def shift(self, final_x, final_y):
        x = self.rect.left + self.rect.width/2
        y = self.rect.top + self.rect.height/2
        if (x == final_x) or (y == final_y):
            return True   # 表示已到目标
        maxSpan = 5
        spd = 5
        dist = 0
        if (x < final_x):
            dist = math.ceil( (final_x - x)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.left += dist
        elif (x > final_x):
            dist = math.ceil( (x - final_x)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.left -= dist
        if (y < final_y):
            dist = math.ceil( (final_y - y)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.top += dist
        elif (y > final_y):
            dist = math.ceil( (y - final_y)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.top -= dist
        return False    # 表示未到目标

class MiniFungus(InanimSprite):

    def __init__(self, XRange, y, spd):
        InanimSprite.__init__(self, "miniFungus")
        self.bldColor = (255,190,140,240)
        self.health = MB["miniFungus"].health
        self.coin = 0
        self.push = 0
        self.weight = 0
        self.damage = MB["miniFungus"].damage
        self.dmgType = MB["miniFungus"].dmgType
        self.manner = MB["miniFungus"].manner

        self.image = load("image/stg4/miniFungus.png").convert_alpha()
        if random()<0.5:
            self.image = flip(self.image, True, False)
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.rect.left = randint( XRange[0], XRange[1] )
        self.rect.top = y
        self.speed = list(spd)

    def move(self, delay, sprites, spurtCanvas):
        # 漂浮移动
        self.rect.left += self.speed[0]
        self.rect.top += self.speed[1]
        if self.health<=0:
            spurtCanvas.addExplosion( getPos(self,0.5,0.5), 20, 10, waveColor=self.bldColor, spatColor=self.bldColor )
            self.kill()
        if not delay%8:
            spurtCanvas.addTrails([2,3,4], [20,22,24], self.bldColor, getPos(self,random(),0.6))
        # 检查出界
        if self.rect.right<0 or self.rect.left>spurtCanvas.rect.width or self.rect.bottom<0 or self.rect.top>spurtCanvas.rect.height:
            self.health = 0
            self.kill()
        # 千里送人头
        if cldList(self, sprites):
            self.hitted( self.health, 0, "physical")

    def stun(self, duration):
        pass

    def hitted(self, damage, pushed, dmgType):
        # decrease health
        self.health -= damage
        if self.health <= 0:
            self.health = 0
            return True

    def drawHealth(self, surface):
        pass


# ========================================================================
# --------------------------------- CP 5 ---------------------------------
# ========================================================================
class blizzardGenerator():
    # 借助model的spurtcanvas绘制。自身并不维护一个画布。
    def __init__(self, bg_size, TMin, TMax):
        self.cntDown = 1600
        self.bg_size = bg_size
        self.phase = 0
        self.freqRange = range(TMin, TMax, 50)
    
    def storm(self, sprites, wind, spurtCanvas, phase):
        self.phase = phase
        # 不同区域设置不同的频率。
        if phase == 0:
            self.freqRange = range(1500, 2000, 50)
        if phase == 1:
            self.freqRange = range(1400, 1800, 50)
        elif phase == 2:
            self.freqRange = range(1200, 1600, 50)
        self.cntDown -= 1
        if self.cntDown <= 60:
            spurtCanvas.addFlakes( 3, wind )
            if self.cntDown <= 0:
                for each in sprites:
                    each.freeze(2)
                self.cntDown = choice( self.freqRange )
    
    def paint(self, dist):
        pass

# ----------------------------
class Wolf(Monster):  
    imgLib = None
    shadLib = None
    snd = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLib:
            Wolf.imgLib = {
                "iList": createImgList("image/stg5/wolf0.png","image/stg5/wolf1.png","image/stg5/wolf2.png",
                    "image/stg5/wolf3.png","image/stg5/wolf4.png","image/stg5/wolf5.png")
            }
            Wolf.shadLib = getShadLib(Wolf.imgLib)
            Wolf.snd = pygame.mixer.Sound("audio/wolf.wav")
        
        # calculate its position
        Monster.__init__(self, "wolf", (255,0,0,240), 8, 1, onlayer, sideGroup)
        self.wallList = []       # 存储本行的所有砖块; # 每次初始化一个新实例时，清空此类的wallList（否则会在上一个实例的基础上再加！）
        posList = []             # 辅助列表，用于暂时存储本行砖块的位置（左边线）
        for aWall in wallGroup:  # 由于spriteGroup不好进行索引/随机选择操作，因此将其中的sprite逐个存入列表中存储
            self.wallList.append(aWall)
            posList.append(aWall.rect.left)
        wall = choice(self.wallList)
        leftMax = wall.rect.left
        rightMax = wall.rect.right       # note：此处砖块的右坐标即下一砖块的左坐标
        tList1 = [ [leftMax,rightMax] ]
        tList2 = [ [leftMax,rightMax] ]
        i1 = 0       # 辅助变量，用于在循环过程中指示当前正在处理列表中的哪一项scope。每当新加一个scope项时，i应+1
        while True:
            if (leftMax-blockSize) in posList:
                leftMax -= blockSize
                tList1[i1][0] = leftMax
            elif (leftMax-2*blockSize) in posList:
                leftMax -= 2*blockSize
                tList1.append( [leftMax,leftMax+blockSize] )
                i1 += 1
            else:
                break
        i2 = 0
        while True:
            if rightMax in posList:
                rightMax += blockSize
                tList2[i2][1] = rightMax
            elif (rightMax+blockSize) in posList:
                rightMax += 2*blockSize
                tList2.append( [rightMax-blockSize,rightMax] )
                i2 += 1
            else:
                break
        tList = tList1+tList2
        self.scopeList = []
        for item in tList:
            if item not in self.scopeList:
                self.scopeList.append(item)
        #另一种去除重复元素的方法是：先转换为集合set（），再转换回列表list（set（））。但由于列表元素（每个item都是list）是不可哈希的，因此不能转换为集合，这里不适合此方法。
        self.scope = (leftMax, rightMax)
        # initialize the sprite
        self.imgIndx = 0
        self.setImg("iList",0)
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left+wall.rect.width//2-self.rect.width//2
        self.rect.bottom = wall.rect.top
        self.reset()
        self.alterSpeed( choice( [-2, 0, 2] ) )
        self.jumping = False
        self.status = "wandering"          # wandering表示闲逛的状态，alarming表示发现英雄的状态

    # 这个move()函数是供外界调动的接口，这里仅起根据传入的英雄参数判断状态的作用。判断完成后，修改自身的状态，然后执行相应的函数。
    def move(self, delay, sprites, spurtCanvas):
        self.checkHitBack(obstacle=True)
        self.count_stun()

        if self.stun_time==0:
            for hero in sprites:
                # 如果有英雄在同一层，则将速度改为朝英雄方向。(这里的两套体系，英雄的层数为偶数，而怪物用的层数都是奇数)
                if (hero.onlayer-1)==self.onlayer and ( self.scope[0]<=getPos(hero,1,0.5)[0] ) and ( getPos(hero,0,0.5)[0]<=self.scope[1] ):
                    self.status = "alarming"
                    self.tgt = hero
                    break      # ***这里碰到第一个英雄符合条件就退出了。因此，如果两个英雄同时在一层中，P1总是会被针对，而P2永远不会被选中为目标。问题留着以后修正。
                else:
                    self.status = "wandering"
        if self.status == "wandering":
            self.wander( delay, spurtCanvas )
        elif self.status == "alarming":
            self.attack( sprites )
        self.checkImg(delay)

    def checkImg(self, delay):
        trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]
        # renew the image of the wolf
        notIn = 0
        for scope in self.scopeList:
            if (getPos(self,0.3,1)[0] >= scope[0]) and (getPos(self,0.7,1)[0] <= scope[1]):
                self.jumping = False
                break
            else:
                notIn += 1
        if notIn >= len(self.scopeList):        # 本狼不在任何一个合理的scope内，因此判定是在空中
            self.jumping = True
            self.imgIndx = 3
            self.setImg("iList",self.imgIndx)
        else:
            if self.speed and not (delay % 5 ):
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
            elif self.speed==0:
                self.imgIndx = 0
            self.setImg("iList",self.imgIndx)
        self.rect = self.image.get_rect()
        self.rect.left = trPos[0]-self.rect.width//2
        self.rect.bottom = trPos[1]

    def wander(self, delay, canvas):
        if (self.speed):                        # speed!=0，在运动。
            if not self.jumping:
                if self.stun_time==0:       # 地面状态才可考虑stun效果
                    self.rect.left += self.speed
                    if self.imgIndx in (4,5):
                        canvas.addSpatters( 2, (1,2,3), [10,12,14], (255,255,255,210), getPos(self,0.25+random()*0.5,1), True )
            else:
                self.rect.left += self.speed*1.5
            if (getPos(self, 0.7, 1)[0] >= self.scope[1] and self.speed > 0) or (getPos(self, 0.3, 1)[0] <= self.scope[0] and self.speed < 0):
                self.alterSpeed(-self.speed)
            if not self.jumping and not delay % 20 and random()<0.08:
                self.alterSpeed(0)
        elif not delay % 20 and random()<0.08:  # 否则，在休息。此时若随机数满足条件，进入奔跑状态
            self.alterSpeed( choice( [2,-2] ) )
    
    def attack(self, sprites):
        if self.stun_time!=0:   # stun状态下不可攻击
            return
        if getPos( self.tgt, 1, 0 )[0]<getPos( self, 0, 0 )[0]:
            self.alterSpeed(-2)
        elif getPos( self.tgt, 0, 0 )[0]>getPos( self, 1, 0 )[0]:
            self.alterSpeed(2)
        if not self.jumping:
            self.rect.left += self.speed * 1.5
        else:
            self.rect.left += self.speed * 2
        if ( self.coolDown==0 ):
            for each in sprites:
                if collide_mask(self, each):
                    self.snd.play(0)           # 撞到英雄，咆哮
                    self.coolDown = 48
        else:
            self.coolDown -= 1
            if ( self.coolDown == 42 ):
                cldList( self, sprites )

    def reset(self):
        self.coolDown = 0
        self.tgt = None             # 指示要攻击的英雄

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)
        for scp in self.scopeList:
            scp[0] += dist
            scp[1] += dist

# -----------------------------
class IceTroll(Monster):
    imgLib = None
    shadLib = None
    snd = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLib:
            IceTroll.imgLib = {
                "iList": createImgList("image/stg5/iceTroll0.png","image/stg5/iceTroll1.png",
                    "image/stg5/iceTroll2.png","image/stg5/iceTroll1.png",
                    "image/stg5/iceTroll0.png","image/stg5/iceTroll3.png",
                    "image/stg5/iceTroll4.png","image/stg5/iceTroll3.png"),
                "att": createImgList("image/stg5/iceTrollAtt.png"),
                "alarm": createImgList("image/stg5/alarmLeft.png")
            }
            IceTroll.shadLib = getShadLib(IceTroll.imgLib)
            IceTroll.snd = pygame.mixer.Sound("audio/iceTroll.wav")
        
        # calculate its position
        Monster.__init__(self, "iceTroll", (255,0,0,240), 5, 3, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.damage = MB["iceTroll"].damage
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left
        self.rect.bottom = wall.rect.top
        self.alterSpeed( choice([-1,1]) )
        self.hitAccum = 0

    def move(self, delay, sprites, canvas):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        if self.stun_time==0:
            if (self.airCnt==0):
                # Check Hero and Turn.
                if not delay%5:
                    for hero in sprites:
                        heroPos = getPos(hero,0.5,0)
                        myPos = getPos(self,0.5,0)
                        # 如果有英雄在同一层，则将速度改为朝英雄方向。
                        if (hero.onlayer-1)==self.onlayer:
                            # 判断是否需要转向
                            if ( self.scope[0]<=heroPos[0]<=self.scope[1] ):
                                if self.speed*( heroPos[0]-myPos[0] ) < 0:
                                    self.alterSpeed(-self.speed)
                                    break     # ***这里碰到第一个英雄符合条件就退出了。因此，如果两个英雄同时在一层中，P1总是会被针对，而P2永远不会被选中为目标。
                            if (self.speed<0 and -175<=heroPos[0]-myPos[0]<0) or (self.speed>0 and 0<heroPos[0]-myPos[0]<175):  # 开喷
                                self.airCnt = 72
                                self.snd.play(0)
                if not (delay % 2):
                    self.rect.left += self.speed
                    if (getPos(self,0.8,0)[0] >= self.scope[1] and self.speed > 0) or (getPos(self,0.2,0)[0] <= self.scope[0] and self.speed < 0):
                        self.alterSpeed(-self.speed)
                if not (delay % 8):
                    self.setImg("iList",self.imgIndx)
                    self.mask = pygame.mask.from_surface(self.image)    # 更新rect，使得与hero重合的判断更加精确
                    self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
            elif (self.airCnt > 0):
                self.airCnt -= 1
                if self.airCnt > 54:
                    self.setImg("alarm")
                else:
                    self.setImg("att")
                    if self.speed <= 0:
                        spd = [ choice([-3,-2]), choice([-3, -2, -1, 1, 2, 3]) ]
                        startX = 0.32
                    elif self.speed > 0:
                        spd = [ choice([2,3]), choice([-3, -2, -1, 1, 2, 3]) ]
                        startX = 0.68
                    # 每次刷新均吐出2个气团
                    canvas.addAirAtoms( self, 2, getPos(self, startX, 0.32), spd, sprites, "freezing" )

    def reportHit(self, tgt):
        self.hitAccum += 1
        if self.hitAccum>=12:
            self.hitAccum = 0
            tgt.hitted( self.damage, self.push, "freezing" )
            tgt.freeze(1)   # 速度-1

    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.airCnt = 0           # indicate if spitting!

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

# -----------------------------------
class IceSpirit(Monster):  
    imgLib = None
    shadLib = None

    def __init__(self, XRange, y, onlayer):
        if not self.imgLib:
            IceSpirit.imgLib = {
                "iList": createImgList("image/stg5/iceSpirit.png")
            }
            IceSpirit.shadLib = getShadLib(IceSpirit.imgLib)

        # initialize the sprite
        Monster.__init__(self, "iceSpirit", (160,220,255,200), 0, 1, onlayer)
        self.setImg("iList",0)
        self.ori_image = self.image.copy()
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.rect.left = randint( XRange[0], XRange[1] )
        self.rect.top = y

        self.alterSpeed(-1)
        self.speed = [0,0]
        self.angle = 0
        self.alterSec = [10,20,30,40]     # 随机在这些刷新次数后偏折方向
        self.cnt = choice(self.alterSec)

    def move(self, delay, sprites, spurtCanvas):
        self.checkHitBack()
        self.count_stun()
        if not (delay % 5 ):
            self.angle = (self.angle+20) % 360
            self.image = rot_center(self.ori_image, self.angle)
            self.mask = pygame.mask.from_surface(self.image)
        # 漂浮移动
        self.rect.left += self.speed[0]
        self.rect.top += self.speed[1]
        if self.stun_time==0:
            # 检查目标，偏折方向
            self.cnt -= 1
            if self.cnt<=0:
                self.cnt = choice(self.alterSec)
                tgt = choice(sprites)
                my_ctr = getPos(self, 0.5, 0.5)
                tgt_ctr = getPos(tgt, 0.5, 0.5)
                if my_ctr[0]>tgt_ctr[0] and self.speed[0]>-3:
                    self.speed[0] -= 1
                elif my_ctr[0]<tgt_ctr[0] and self.speed[0]<3:
                    self.speed[0] += 1
                if my_ctr[1]>tgt_ctr[1] and self.speed[1]>-3:
                    self.speed[1] -= 1
                elif my_ctr[1]<tgt_ctr[0] and self.speed[1]<3:
                    self.speed[1] += 1
        spurtCanvas.addTrails([2,3,5], [16,20,24], (160,220,255,200), getPos(self,random(),0.6))
        hero = cldList(self, sprites)
        if hero:
            # 千里送人头
            hero.preyList.append( (getPos(self,0.5,0.5), self.bldColor, 0, True, self.coin, False) )
            self.hitted( self.full, 0, "physical")

    def hitted(self, damage, pushed, dmgType):
        # decrease health
        true_dmg = round(damage*self.realDmgRate)
        self.health -= true_dmg
        self.msgList.append( [getPos(self,0.5,0.5), str(true_dmg), 60] )
        if self.health <= 0:                # dead。
            self.health = 0
            self.spurtCanvas.addExplosion( getPos(self,0.5,0.5), 28, 12, waveColor=(180,180,240,240), spatColor=(150,150,220,240) )
            self.kill()
            return True
        if pushed>0:   # 向右击退
            self.hitBack = max( pushed-self.weight, 0 )
        elif pushed<0: # 向左击退
            self.hitBack = min( pushed+self.weight, 0 )

# -----------------------------------
class Eagle(Monster):  
    imgLib = None
    shadLib = None

    def __init__(self, XRange, y, onlayer):
        if not self.imgLib:
            Eagle.imgLib = {
                "iList": createImgList("image/stg5/eagleLeft0.png","image/stg5/eagleLeft1.png"),
                "att": createImgList("image/stg5/eagleAtt.png")
            }
            Eagle.shadLib = getShadLib(Eagle.imgLib)
            Eagle.snd = pygame.mixer.Sound("audio/eagle.wav")

        # initialize the sprite
        Monster.__init__(self, "eagle", (255,0,0,240), 8, 1, onlayer)
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.leftBd, self.rightBd= XRange
        self.rect.left = randint( XRange[0], XRange[1] )
        self.rect.top = y
        self.alterSpeed(-1)
        self.nxt = [randint(self.leftBd,self.rightBd), randint(y-10, y+10)]
        self.upDown = 2
        self.bufRange = 1.2

    def move(self, delay, sprites, spurtCanvas):
        self.checkHitBack()
        self.count_stun()
        if not self.charging and not (delay % 6 ):  # 没有俯冲时，正常扇翅
            self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
            self.setImg("iList",self.imgIndx)
            self.rect.top += self.upDown
            self.upDown = -self.upDown
        if self.stun_time==0:
            # find tgt and goes to charge
            if self.cnt == 0:
                self.cnt = randint(170, 210)
                # 获取位置数据
                aim = getPos(choice(sprites),0.5,0.5)
                myPos = getPos( self, 0.5, 0.5 )
                # 如果水平距离hero太近，则先飞远
                if abs(aim[0]-myPos[0])<140:
                    pos1 = randint(self.leftBd-10,self.leftBd+200)
                    pos2 = randint(self.rightBd-200,self.rightBd+10)
                    self.nxt = [choice([pos1, pos2]), randint(40,180)]
                    self.direction = "left" if ( self.nxt[0] < self.rect.left + self.rect.width/2 ) else "right"
                # 否则，就可以冲冲冲
                else:
                    self.snd.play(0)
                    self.charging = True
                    self.dealt = False
                    deltaX = ( aim[0] - myPos[0] )*self.bufRange
                    deltaY = ( aim[1] - myPos[1] )*self.bufRange
                    self.nxt = [myPos[0]+deltaX, myPos[1]+deltaY]
                    self.direction = "left" if ( self.nxt[0] < self.rect.left + self.rect.width/2 ) else "right"
                    if self.direction=="left":
                        self.push = self.pushList[0]
                    else:
                        self.push = self.pushList[1]
                    self.setImg("att")
                    self.rect = self.image.get_rect()
                    self.rect.left = myPos[0]-self.rect.width//2
                    self.rect.top = myPos[1]-self.rect.height//2
                    self.mask = pygame.mask.from_surface(self.image)
            # Adjusting position.
            self.shift( self.nxt[0], self.nxt[1] )
            self.cnt -= 1
            if self.charging:
                spurtCanvas.addTrails([2,3,4], [14,16,20], (210,210,220,200), getPos(self,random(),0.7))
                if not self.dealt and cldList( self, sprites ):
                    self.dealt = True

    def shift(self, final_x, final_y):
        maxSpan = 4
        spd = 5
        dist = 0
        x = self.rect.left + self.rect.width/2
        y = self.rect.top + self.rect.height/2
        if abs(x-final_x)<maxSpan:
            self.charging = False
            myPos = getPos( self, 0.5, 0.5 )
            self.setImg("iList",self.imgIndx)
            self.rect = self.image.get_rect()
            self.rect.left = myPos[0]-self.rect.width//2
            self.rect.top = myPos[1]-self.rect.height//2
            self.mask = pygame.mask.from_surface(self.image)
        if (x < final_x):
            dist = math.ceil( (final_x - x)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.left += dist
        elif (x > final_x):
            dist = math.ceil( (x - final_x)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.left -= dist
        if (y < final_y):
            dist = math.ceil( (final_y - y)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.top += dist
        elif (y > final_y):
            dist = math.ceil( (y - final_y)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.top -= dist
    
    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.cnt = randint(90, 105)       # count for the loop of charging
        self.charging = False
        self.dealt = False

    def erase(self):
        self.snd.stop()
        self.kill()
        del self

    def level(self, dist):
        self.rect.left += dist
        self.nxt[0] += dist
        self.leftBd += dist
        self.rightBd += dist

    def lift(self, dist):
        self.rect.top += dist
        self.nxt[1] += dist
    
# Boss ------------------------------
class FrostTitan(Boss):
    summonAct = 90  # 从0-该数表示召唤状态

    def __init__(self, xRange, y, onlayer, font):
        # initialize the sprite
        Boss.__init__(self, font, "FrostTitan", (250,90,80,240), 4, 4, onlayer, shadOffset=12)
        # ----- body part (the core of the FrostTitan) ------
        self.imgLib = {
            "body": createImgList("image/stg5/FrostTitan1.png","image/stg5/FrostTitan2.png"),
            "summon": createImgList("image/stg5/FrostTitanSummon.png")
        }
        self.shadLib = getShadLib(self.imgLib)
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.xRange = xRange
        # calculate its position
        self.rect = self.image.get_rect()
        self.rect.left = randint( self.xRange[0], self.xRange[1] ) - self.rect.width//2
        self.rect.top = y
        self.alterSpeed(0)
        self.cnt = 1080      # count for the loop of shift position
        self.nxt = (0, 0)
        self.upDown = 2

    def move(self, delay, sprites, canvas, bg_size):
        self.checkHitBack()
        self._tipPosition(canvas)
        self.count_stun()

        if not delay%4:
            self.spurtCanvas.addSmoke(2, (3,5,7), 5, (210,210,255,250), getPos(self,0.5,random()), 30)
            # 上下摆动
            self.rect.top += self.upDown
            self.upDown = - self.upDown
            if self.stun_time==0:
                self.shift( self.nxt[0], self.nxt[1] )
                if not delay % 12:
                    if self.cnt>self.summonAct:     # 平常状态
                        self.imgIndx = (self.imgIndx+1) % len(self.imgLib["body"])
                        self.setImg("body", self.imgIndx)
                    else:           # 召唤状态
                        self.setImg("summon")
                    self.mask = pygame.mask.from_surface(self.image)
        
        if self.stun_time==0:
            # count down for rage actions.
            self.cnt -= 1
            if self.cnt<=0:
                self.cnt = 1580
            else:
                if not delay%60:
                    self.nxt = ( randint( self.xRange[0], self.xRange[1] ), randint(40,520) )   # randomize a new position
                    self.direction = "left" if ( self.nxt[0] < getPos(self, 0.5, 0.5)[0] ) else "right"
            # deal regular snowball attack:
            if not (self.cnt % 12) and (self.coolDown<=0) and (self.cnt>self.summonAct) and random()<0.2:
                #self.growlSnd.play(0)
                self.coolDown = 120
            elif self.coolDown > 0:
                self.coolDown -= 1
                if self.coolDown in (115, 85):
                    return self.makeSnowball( sprites )
            # Create Ice Spirits.
            if self.cnt in (10,35,60):
                myPos = getPos(self,0.1,0.2) if self.direction=="left" else getPos(self,0.9,0.2)
                spirit = IceSpirit(self.xRange, myPos[1], self.onlayer)
                spirit.coin = 0
                spirit.rect.left = myPos[0]-spirit.rect.width//2
                return spirit
        return None
    
    def makeSnowball(self, sprites):
        # Determine tgt and distance
        tgt = choice( sprites )
        aim = getPos( tgt,0.5,0.4 )
        myPos = getPos(self,0.5,0.4)
        deltaX = aim[0] - myPos[0]
        deltaY = aim[1] - myPos[1]
        if deltaX>0:
            spdX = randint(2,5)
        elif deltaX<0:
            spdX = randint(-5,-2)
        else:
            spdX = randint(-1,1)
        if deltaY>0:
            spdY = randint(-9,-3)
        else:
            spdY = randint(-15,-7)
        snowball = SnowBall( myPos, tgt.onlayer-1, (spdX, spdY) )
        return snowball
    
    def reset(self):
        self.imgIndx = 0
        self.setImg("body",0)
        self.coolDown = 0    # count for attack coolDown

    def shift(self, final_x, final_y):
        x = self.rect.left + self.rect.width/2
        y = self.rect.top + self.rect.height/2
        if (x == final_x) or (y == final_y):
            return True   # 表示已到目标
        maxSpan = 4
        spd = 5
        dist = 0
        if (x < final_x):
            dist = math.ceil( (final_x - x)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.left += dist
        elif (x > final_x):
            dist = math.ceil( (x - final_x)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.left -= dist
        if (y < final_y):
            dist = math.ceil( (final_y - y)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.top += dist
        elif (y > final_y):
            dist = math.ceil( (y - final_y)/spd )
            if dist > maxSpan:
                dist = maxSpan
            self.rect.top -= dist
        return False    # 表示未到目标

class SnowBall(pygame.sprite.Sprite):
    def __init__(self, pos, layer, spd, main=True):   # 参数pos为本对象初始的位置
        pygame.sprite.Sprite.__init__(self)
        self.main = main    # 为True表示是大雪球，还可以分成小雪球
        if self.main==True:
            self.oriImage = load("image/stg5/snowball.png").convert_alpha()
        else:
            self.oriImage = pygame.transform.smoothscale( load("image/stg5/snowball.png").convert_alpha(), (45,45) )
        
        self.image = self.oriImage
        self.rect = self.image.get_rect()
        self.rect.left = pos[0]-self.rect.width//2
        self.rect.top = pos[1]-self.rect.height//2
        self.mask = pygame.mask.from_surface(self.image)
        self.speed = list(spd)
        self.deg = 0
        if spd[0]>0:
            self.push = 10
        else:
            self.push = -10
        self.damage = MB["FrostTitan"].damage
        self.dmgType = MB["FrostTitan"].dmgType
        self.category = "snowball"
        self.blastSnd = pygame.mixer.Sound("audio/wizard/hit.wav")
        self.onlayer = layer
        self.colorSet = [(200,200,255,240), (180,180,240,240), (150,150,220,240)]

    def move(self, delay, sideWalls, downWalls, keyLine, sprites, canvas, GRAVITY):
        if pygame.sprite.spritecollide(self, downWalls, False, collide_mask) or pygame.sprite.spritecollide(self, sideWalls, False, collide_mask):
            return self.explode(canvas)
        # generate some sparks
        if not delay%2:
            self.deg = (self.deg+20) % 360
            self.image = rot_center(self.oriImage, self.deg) if self.speed[0]<=0 else rot_center(self.oriImage, -self.deg)
            self.mask = pygame.mask.from_surface(self.image)
            canvas.addTrails( [4,5,6], [12,16,20,24,28], choice(self.colorSet), getPos(self, 0.3+random()*0.4, 0.3+random()*0.4) )
        if cldList(self, sprites):
            return self.explode(canvas)
        # move the object
        self.rect.left += self.speed[0]
        self.rect.top += self.speed[1]
        if self.speed[1]<GRAVITY-1 and not delay%2:     # 雪球的最大下落速度要稍微慢一些
            self.speed[1] += 1
        return None

    def explode(self, canvas):
        self.blastSnd.play(0)
        canvas.addExplosion(getPos(self,0.5,0.5), 28, 14, waveColor=self.colorSet[1], spatColor=self.colorSet[2])
        self.kill()
        # 若为大雪球，还要分成小雪球
        ballList = []
        if self.main==True:
            for i in range(3):
                pos = getPos(self,0.5,0.5)
                spd = ( randint(-6,6), choice([-8,-7,-6]) )
                ball = SnowBall(pos, self.onlayer, spd, main=False)
                ball.damage //= 3
                ballList.append( ball )
        del self
        return ballList
    
    def paint(self, surface):
        surface.blit( self.image, self.rect )
    
    def lift(self, dist):
        self.rect.bottom += dist

    def level(self, dist):
        self.rect.left += dist
    

# ========================================================================
# --------------------------------- CP 6 ---------------------------------
# ========================================================================
class Dwarf(Monster):
    imgLib = None
    shadLib = None
    snd = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLib:
            Dwarf.imgLib = {
                "iList": createImgList("image/stg6/dwarf0.png","image/stg6/dwarf1.png","image/stg6/dwarf2.png","image/stg6/dwarf1.png")
            }
            Dwarf.shadLib = getShadLib(Dwarf.imgLib)
            Dwarf.snd = pygame.mixer.Sound("audio/wolf.wav")
        
        # calculate its position
        Monster.__init__(self, "dwarf", (255,0,0,240), 5, 1, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left+wall.rect.width//2-self.rect.width//2
        self.rect.bottom = wall.rect.top
        self.alterSpeed( choice( [-1, 0, 1] ) )
        self.status = "wandering"          # wandering表示闲逛的状态，alarming表示发现英雄的状态

    # move()-供外界调动的接口，这里仅起根据传入的英雄参数判断状态的作用。判断完成后，修改自身的状态，然后执行相应的函数。
    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()

        if self.stun_time==0:
            for hero in sprites:
                # 如果有英雄在同一层，则将速度改为朝英雄方向。(两套体系：英雄的层数为偶数，而怪物用的层数都是奇数)
                if (hero.onlayer-1)==self.onlayer and ( self.scope[0]<=getPos(hero,1,0.5)[0] ) and ( getPos(hero,0,0.5)[0]<=self.scope[1] ):
                    self.status = "alarming"
                    self.tgt = hero
                    break     # ***这里碰到第一个英雄符合条件就退出了。因此，如果两个英雄同时在一层中，P1总是会被针对，P2永远不会被选中为目标。问题留着以后修正。
                else:
                    self.status = "wandering"
            if self.status == "wandering":
                self.wander( delay )
            elif self.status == "alarming":
                if getPos( self.tgt, 0.5, 0.5 )[0]>getPos( self, 0.5, 0.5 )[0]:
                    self.alterSpeed(1)
                else:
                    self.alterSpeed(-1)
                self.attack( sprites )
            self.checkImg(delay)

    def checkImg(self, delay):
        trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]
        # renew the image
        if self.speed and not (delay % 8 ):
            self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
        elif self.speed == 0:
            self.imgIndx = 0
        self.setImg("iList",self.imgIndx)
        self.rect = self.image.get_rect()
        self.rect.left = trPos[0]-self.rect.width//2
        self.rect.bottom = trPos[1]

    def wander(self, delay):
        if (self.speed):                        # speed!=0，在运动。
            self.rect.left += self.speed
            if (getPos(self, 0.7, 1)[0] >= self.scope[1] and self.speed > 0) or (getPos(self, 0.3, 1)[0] <= self.scope[0] and self.speed < 0):
                self.alterSpeed( -self.speed )
            if not delay % 20 and random()<0.08:
                self.alterSpeed(0)
        elif not delay % 20 and random()<0.08:  # 否则，在休息。此时若随机数满足条件，进入奔跑状态
            self.alterSpeed( choice( [1,-1] ) )
    
    def attack(self, sprites):
        self.rect.left += self.speed * 2
        if ( self.coolDown<=0 ):
            for each in sprites:
                if collide_mask(self, each):
                    self.snd.play(0)    # 撞到英雄，咆哮
                    self.coolDown = 48
        else:
            self.coolDown -= 1
            if ( self.coolDown == 38 ):
                cldList( self, sprites )

    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.coolDown = 0
        self.tgt = None                    # 指示要攻击的英雄

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

# ------------------------------------
class Gunner(Monster):
    imgLib = None
    shadLib = None
    fireSnd = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        if not self.imgLib:
            Gunner.imgLib = {
                "iList": createImgList("image/stg6/gunner0.png","image/stg6/gunner1.png"),
                "fire": createImgList("image/stg6/gunnerFire.png")
            }
            Gunner.shadLib = getShadLib(Gunner.imgLib)
            Gunner.fireSnd = pygame.mixer.Sound("audio/gunner.wav")
        
        # calculate its position
        Monster.__init__(self, "gunner", (20,20,20,240), 0, 2, onlayer, sideGroup, debri=("metalDebri",6))
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left+wall.rect.width//2-self.rect.width//2
        self.rect.bottom = wall.rect.top
        self.eyePos = getPos(self, 0.5, 0.2)
        self.snd = pygame.mixer.Sound("audio/wolf.wav")
        self.insp = self.inspRange = 360   # inspRange是原始参数，insp是不断变化的参数
        self.alterSpeed( choice( [-1, 1] ) )
        self.status = "wandering"          # wandering表示闲逛的状态，alarming表示发现英雄的状态
        self.newBullet = None

    # 这个move()函数是供外界调动的接口，这里仅起根据传入的英雄参数判断状态的作用。判断完成后，修改自身的状态，然后执行相应的函数。
    def move(self, delay, sprites, screen):
        self.checkHitBack(obstacle=True)
        self.count_stun()
        if self.stun_time==0:
            for hero in sprites:
                # 如果有英雄在同一层，则将速度改为朝英雄方向。(这里的两套体系，英雄的层数为偶数，而怪物用的层数都是奇数)
                if self.coolDown>0 or \
                    ( hero.rect.top<=self.eyePos[1]<=hero.rect.bottom and ( (self.direction=="left" and self.eyePos[0]+self.insp<=getPos(hero,0.5,0.5)[0]<=self.eyePos[0]) or (self.direction=="right" and self.eyePos[0]<=getPos(hero,0.5,0.5)[0]<=self.eyePos[0]+self.insp) ) ):
                    self.status = "alarming"
                    break     # ***这里碰到第一个英雄符合条件就退出了。因此，如果两个英雄同时在一层中，P1总是会被针对，而P2永远不会被选中为目标。问题留着以后修正。
                else:
                    self.status = "wandering"
            if self.status == "wandering":
                self.patrol( delay )
            elif self.status == "alarming" or self.coolDown>0:
                self.speed = 0
                self.fire()
            # renew the image of the gunner; if its speed = 0, do not change image
            trPos = [ self.rect.left+self.rect.width//2, self.rect.bottom ]
            self.setImg("iList",self.imgIndx)
            if self.speed and not (delay % 5 ):
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
            elif 86>=self.coolDown>=83 or 81>=self.coolDown>=78 or 76>=self.coolDown>=73:
                self.setImg("fire")
            self.rect = self.image.get_rect()
            self.rect.left = trPos[0]-self.rect.width//2
            self.rect.bottom = trPos[1]
        # inspecting line
        self.eyePos = getPos(self, 0.5, 0.2)
        pygame.draw.line( screen, (255,0,0), self.eyePos, (self.eyePos[0]+self.insp,self.eyePos[1]), choice([1,2]) )

    def patrol(self, delay):
        if (self.speed):                        # speed!=0，在运动。
            self.rect.left += self.speed
            if (getPos(self, 0.7, 1)[0] >= self.scope[1] and self.speed > 0) or (getPos(self, 0.3, 1)[0] <= self.scope[0] and self.speed < 0):
                self.alterSpeed( -self.speed )
            if not delay % 20 and random()<0.08:
                self.speed = 0
        elif not delay % 20 and random()<0.08:  # 否则，在休息。此时若随机数满足条件，进入移动状态。
            self.alterSpeed( choice( [1,-1] ) )
    
    def fire(self):
        if ( self.coolDown<=0 ):
            self.coolDown = 90
            self.fireSnd.play(0)
        if self.coolDown==85 or self.coolDown==80 or self.coolDown==75:
            bullet = GunBullet(getPos(self, 0, 0.4), -5) if self.direction=="left" else GunBullet(getPos(self, 1, 0.4), 5)
            self.newBullet = bullet
        self.coolDown -= 1
    
    def alterSpeed(self, speed):
        self.speed = speed
        if speed > 0:
            self.direction = "right"
            self.insp = self.inspRange
        elif speed < 0:
            self.direction = "left"
            self.insp = -self.inspRange
    
    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.coolDown = 0
    
    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

class GunBullet(InanimSprite): 
    imgList = None
    shadList = None

    def __init__(self, pos, spd):
        if not self.imgList:
            tmpImg = load("image/princess/arrow_left.png").convert_alpha()
            GunBullet.imgList = {
                "left": pygame.transform.smoothscale( tmpImg, (8,8) ),
                "right": pygame.transform.smoothscale( flip(tmpImg, True, False), (8,8) )
            }
            GunBullet.shadList = {}
            for dir in GunBullet.imgList:     # 对于该动作的每一方向
                GunBullet.shadList[dir] = generateShadow(GunBullet.imgList[dir])
        
        InanimSprite.__init__(self, "gunBullet")
        self.speed = spd
        if spd > 0:
            self.direction = "right"
            self.push = 5
        else:
            self.direction = "left"
            self.push = -5
        self.image = self.imgList[self.direction]
        self.shade = self.shadList[self.direction]
        self.dmgType = MB["gunner"].dmgType
        self.damage = MB["gunner"].damage
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = pos[0]-self.rect.width//2
        self.rect.top = pos[1]-self.rect.height//2
    
    def update(self, tgts, wallList, screenWidth, canvas):
        self.rect.left += self.speed
        for each in wallList:
            if ( collide_mask(self,each) ):  # 撞墙
                self._explode(canvas)
                return
        if self.rect.left>=screenWidth or self.rect.right<=0: # 出界
            self._explode(canvas)
            return
        elif cldList(self, tgts):
            self._explode(canvas)
            return
    
    def paint(self, surface):
        # 画阴影
        shadRect = self.rect.copy()
        shadRect.left -= 4
        surface.blit(self.shade, shadRect)
        surface.blit(self.image, self.rect)
    
    def _explode(self, canvas):
        canvas.addSpatters(4,(2,4),(7,9,10),(20,10,10,240),(self.rect.left+self.rect.width//2,self.rect.top+self.rect.height//2),True)
        self.kill()
        del self

# -----------------------------------
class Lasercraft(Monster):  
    imgLib = None
    shadLib = None

    def __init__(self, align, y, onlayer):
        if not self.imgLib:
            Lasercraft.imgLib = {
                "iList": createImgList("image/stg6/lasercraft0.png","image/stg6/lasercraft1.png", "image/stg6/lasercraft2.png","image/stg6/lasercraft1.png")
            }
            Lasercraft.shadLib = getShadLib(Lasercraft.imgLib)
            Lasercraft.sparkySnd = pygame.mixer.Sound("audio/sparky.wav")

        # initialize the sprite
        Monster.__init__(self, "lasercraft", (110,250,10,240), 6, 1, onlayer, debri=("metalDebri",6))
        
        self.alterSpeed( choice([-1, 1]) )
        if self.direction == "left":
            self.align = align[1]
            self.limitX = align[0]    # 发射时的激光终点
        else:
            self.align = align[0]
            self.limitX = align[1]
        self.reset()
        # calculate its position
        self.rect = self.image.get_rect()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect.left = self.align - self.rect.width//2
        self.rect.top = y
        if self.direction == "left":
            self.muzzle = getPos(self, 0.12, 0.65)  # 发射时的炮口坐标
        else:
            self.muzzle = getPos(self, 0.88, 0.65)
        self.nxt = self.rect.top+self.rect.height//2         # 下一个悬停处的竖坐标      

    def move(self, delay, sprites, maxLayer):
        if not self.checkHitBack():
            gap = self.align - (self.rect.left+self.rect.width//2)
            if gap:
                self.rect.left = self.rect.left + gap//2
        self.count_stun()

        if not ( delay% 4):
            trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom - self.rect.height//2 ]
            self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
            self.setImg("iList",self.imgIndx)
            self.rect = self.image.get_rect()
            self.rect.left = trPos[0]-self.rect.width//2
            self.rect.bottom = trPos[1]+self.rect.height//2
        if self.stun_time==0:
            # charging motion
            if not (delay % 3):
                self.shift( self.nxt )
                self.cnt -= 1
                # find new position
                if self.cnt <= 0:
                    self.cnt = randint(80,120)
                    tgt = choice(sprites)
                    if tgt.onlayer > 2 and tgt.onlayer < maxLayer:
                        self.nxt = tgt.rect.top + tgt.rect.height//2
            # 某科学的电磁炮，发射！
            if self.coolDown==40:
                self.chargeList.clear()
                self.sparkySnd.play(0)
            elif 15 < self.coolDown < 40:  # 蓄力充能阶段
                if random()<0.4:           # 添加新粒子
                    r = choice( [2,3,4] )
                    XRange = list( range(self.muzzle[0]-50,self.muzzle[0]-30) ) + list( range(self.muzzle[0]+30,self.muzzle[0]+50) )
                    YRange = list( range(self.muzzle[1]-50,self.muzzle[1]-30) ) + list( range(self.muzzle[1]+30,self.muzzle[1]+50) )
                    pos = [ choice( XRange ), choice( YRange ) ]
                    color = choice( [(240,240,255,240),(170,170,255,240),(110,110,250,240)] )
                    self.chargeList.append( (r, pos, color) ) 
            elif self.coolDown<15:
                for each in sprites:
                    if ( ( self.direction=="right" and getPos(each,0.5,0.5)[0]>self.muzzle[0] ) or ( self.direction=="left" and getPos(each,0.5,0.5)[0]<self.muzzle[0] ) ) and (each.rect.top < self.muzzle[1] < each.rect.bottom): # 被激光击中！！！
                        each.hitted( self.damage, self.push, MB["lasercraft"].dmgType )
                if (self.coolDown <= 0):
                    self.coolDown = randint(160,240)
            self.coolDown -= 1

    def shift(self, final_y):
        y = self.rect.top + self.rect.height/2
        if (y == final_y):
            return True
        elif (y < final_y):
            dist = min( math.ceil( (final_y - y)/4 ), 8 )
            self.rect.top += dist
            self.muzzle[1] += dist
        elif (y > final_y):
            dist = min( math.ceil( (y - final_y)/4 ), 8 )
            self.rect.top -= dist
            self.muzzle[1] -= dist
    
    def paint(self, surface):
        # 画阴影
        shadRect = self.rect.copy()
        shadRect.left -= self.shadOffset
        surface.blit(self.shad, shadRect)
        surface.blit(self.image, self.rect)
        # 画打击阴影
        if self.hitBack:
            surface.blit( self.shad, self.rect )
        if self.coolDown<40:
            if self.coolDown>=15:
                for each in self.chargeList:   # 绘制并移动粒子
                    pygame.draw.circle( surface, each[2], each[1], each[0] )  # 充能粒子
                    each[1][0] += (self.muzzle[0]-each[1][0]) // 8
                    each[1][1] += (self.muzzle[1]-each[1][1]) // 8
            else:
                pygame.draw.line( surface, (120,120,250), self.muzzle, (self.limitX,self.muzzle[1]), choice([4,6,8]))   # 开炮！！
            pygame.draw.circle( surface, (120,120,250), self.muzzle, randint(14,20) )   #聚能中心
    
    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.cnt = 0         # count for the loop of shift position
        self.coolDown = 160  # count for attack coolDown
        self.chargeList = [] # 用于存放电磁炮蓄力充能时的充能粒子信息 

    def level(self, dist):
        self.rect.left += dist
        self.align += dist
        self.muzzle[0] += dist
        self.limitX += dist

    def lift(self, dist):
        self.rect.top += dist
        self.nxt += dist
        self.muzzle[1] += dist

# Boss ------------------------------
class WarMachine(Boss):
    arm = None        # 是一个单独的sprite
    packet = None

    def __init__(self, groupList, onlayer, font):
        # initialize the sprite
        Boss.__init__(self, font, "WarMachine", (10,30,10,240), 6, 4, onlayer)
        self.initLayer(groupList)
        # ----- body part (the core of the WarMachine) ------
        self.imgLib = {
            "bodyList": createImgList("image/stg6/WarMachine0.png","image/stg6/WarMachine1.png")
        }
        self.shadLib = getShadLib(self.imgLib)
        self.imgIndx = 0
        self.setImg("bodyList",0)
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = self.initPos[0]-self.rect.width//2
        self.rect.bottom = self.initPos[1]
        self.coolDown = 0           
        self.alterSpeed( choice( [-1, 1] ) )
        # ------------- arm part --------------
        self.armLeft = [ pygame.image.load("image/stg6/arm.png").convert_alpha(), pygame.image.load("image/stg6/armFire.png").convert_alpha() ]
        self.armRight = [ pygame.transform.flip(self.armLeft[0], True, False), pygame.transform.flip(self.armLeft[1], True, False) ]
        self.armR = { "left":[ (0.5,0.4), (0.5,0.4) ], "right":[ (0.5,0.4), (0.5,0.4) ] }     # 分别为左和右时的位置信息
        self.arm = Ajunction( self.armLeft[0], getPos(self, self.armR[self.direction][0][0], self.armR[self.direction][0][1]) )
        self.armIndx = 0
        # ------------- packet part ----------------
        self.pktLeft = [ pygame.image.load("image/stg6/packet.png").convert_alpha(), pygame.image.load("image/stg6/packetBroken.png").convert_alpha() ]
        self.pktRight = [ pygame.transform.flip(self.pktLeft[0], True, False), pygame.transform.flip(self.pktLeft[1], True, False) ]
        self.pktR = { "left":[ (0.75,0.42), (0.75,0.42) ], "right":[ (0.25,0.42), (0.25,0.42) ] }
        self.packet = Ajunction( self.pktLeft[0], getPos(self, self.pktR[self.direction][0][0], self.pktR[self.direction][0][1]) )
        self.pktIndx = 0
        # ----------- other attributes -------------------------
        self.cnt = 0         # count for the loop of shift position
        self.coolDown = 0    # count for attack coolDown
        self.fireSnd = pygame.mixer.Sound("audio/MachineGrenade.wav")
        self.moanSnd = pygame.mixer.Sound("audio/MachineCollapse.wav")
        self.jetting = False
        self.jetImg = [ pygame.image.load("image/stg6/jet0.png").convert_alpha(), pygame.image.load("image/stg6/jet1.png").convert_alpha() ]
        self.jetIndx = 0
        self.msCnt = 0

    def move(self, delay, sprites, canvas, tower):
        self.checkHitBack(obstacle=True)
        self._tipPosition(canvas)
        
        if not ( delay % 2 ):
            #优先处理 jetting 
            if self.jetting:
                self.rect.bottom += ( (self.initPos[1]-getPos(self, 0.5, 1)[1]) // 10 )
                self.rect.left += ( (self.initPos[0]-getPos(self, 0.5, 1)[0]) // 12 )
                #以竖直方向为标准，若已抵达(等于或略高于)目标行，则将jetting标记为False
                if 0<= (self.initPos[1]-self.rect.bottom) < 10:
                    self.rect.bottom = self.initPos[1]
                    self.jetting = False
                self.jetIndx = (self.jetIndx+1) % len(self.jetImg)
            # 然后处理 火箭炮
            elif self.msCnt>0:
                self.msCnt -= 1
                if self.msCnt in (20,30,40):
                    if self.direction=="left":
                        return Missle( getPos(self.arm,0,0.85), self.direction, MB["missle"].damage, choice(sprites) )
                    elif self.direction=="right":
                        return Missle( getPos(self.arm,1,0.85), self.direction, MB["missle"].damage, choice(sprites) )
            # 只有不在jet 且没有发射missle 的时候才可以做自由水平移动
            else:
                self.armIndx = 0  # 重置手势
                self.rect.left += self.speed
                if (self.rect.right >= self.scope[1] and self.speed > 0) or (self.rect.left <= self.scope[0] and self.speed < 0):
                    self.alterSpeed(-self.speed)
                if not delay%6:
                    self.imgIndx = (self.imgIndx+1) % len(self.imgLib["bodyList"]["left"])
            # 更新各组件的图像
            self.setImg("bodyList", self.imgIndx)
            if self.direction == "left":
                self.mask = pygame.mask.from_surface(self.image)
                self.packet.updateImg( self.pktLeft[self.pktIndx] )
                self.arm.updateImg( self.armLeft[self.armIndx] )
            elif self.direction == "right":
                self.mask = pygame.mask.from_surface(self.image)
                self.packet.updateImg( self.pktRight[self.pktIndx] )
                self.arm.updateImg( self.armRight[self.armIndx] )
        # Anyway we should 及时更新ajunction的位置（还有击退）
        self.packet.updatePos( getPos(self, self.pktR[self.direction][self.pktIndx][0], self.pktR[self.direction][self.pktIndx][1]) )
        self.arm.updatePos( getPos(self, self.armR[self.direction][self.armIndx][0], self.armR[self.direction][self.armIndx][1]) )
        # change layer
        if not (delay%60) and self.msCnt==0:
            if random()<0.1:
                self.jetting = True
                # 处理层数。需要在合理的范围内
                psbLayer = [ max(self.onlayer-2,-1), min(self.onlayer+2,tower.layer-1) ]
                self.onlayer = choice( psbLayer )
                self.initLayer(tower.groupList)
            # 随机概率发射火箭炮！
            elif (not self.jetting) and random()<0.16:
                self.armIndx = 1
                self.msCnt = 60
        # Check coolDown and fire the back 榴弹packet.
        if self.coolDown == 0:
            self.coolDown = randint(145,155)
        elif (self.coolDown > 0):
            self.coolDown -= 1
            if self.coolDown in [140,130,120,110]:
                self.fireSnd.play(0)
                return Fire( getPos(self.packet,0.5,0), self.onlayer, randint(-3,3), randint(-6,-4))

    def stun(self, duration):
        pass

    def lift(self, dist):
        self.rect.bottom += dist
        self.initPos[1] += dist
    
    def level(self, dist):
        self.rect.left += dist
        self.initPos[0] += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)

    def paint(self, screen):
        # 画阴影
        shadRect = self.rect.copy()
        shadRect.left -= 8
        screen.blit(self.shad, shadRect)
        if self.jetting:
            jetRect = self.jetImg[self.jetIndx].get_rect()
            jetRect.left, jetRect.top = getPos(self, 0.2, 1)
            screen.blit( self.jetImg[self.jetIndx], jetRect )
            jetRect.left, jetRect.top = getPos(self, 0.8, 1)
            screen.blit( self.jetImg[self.jetIndx], jetRect )
        screen.blit( self.image, self.rect )
        # 画打击阴影
        if self.hitBack:
            screen.blit( self.shad, self.rect )
        screen.blit( self.packet.image, self.packet.rect )
        screen.blit( self.arm.image, self.arm.rect )

    def erase(self):
        self.moanSnd.play(0)
        self.packet.kill()
        self.arm.kill()
        del self.packet, self.arm
        self.kill()

class Missle(InanimSprite):
    oriImg = {"left":None, "right":None}
    fullSpd = 5
    blastSnd = None
    launchSnd = None

    def __init__(self, pos, direction, damage, tgt=None):
        if not Missle.oriImg["left"]:
            Missle.oriImg = { "left": load("image/stg6/missle.png").convert_alpha(),
                "right":flip(load("image/stg6/missle.png").convert_alpha(), True, False) }
            Missle.blastSnd = pygame.mixer.Sound("audio/wizard/hit.wav")
            Missle.launchSnd = pygame.mixer.Sound("audio/missle.wav")

        InanimSprite.__init__(self, "missle")
        self.launchSnd.play(0)
        if direction=="right":      # 为方便角度计算，以x向右为正方向、y向上为正方向
            self.speed = [self.fullSpd, 0]
            self.push = 9
        else:
            self.speed = [-self.fullSpd, 0]
            self.push = -9
        self.image = self.oriImg[direction]
        self.rect = self.image.get_rect()
        self.rect.left = pos[0]-self.rect.width//2
        self.rect.top = pos[1]-self.rect.height//2
        self.mask = pygame.mask.from_surface(self.image)
        self.damage = damage
        self.health = MB["missle"].health
        self.dmgType = MB["missle"].dmgType
        self.coin = MB["missle"].coin
        self.manner = MB["missle"].manner
        self.tgt = tgt
        if not self.tgt:     # no tgt，直接boom
            self.health = 0
        self.bldColor = (10,40,20,240)

    def update(self, delay, canvas):
        if self.health<=0:
            self._explode(canvas)
            return None
        # alter img
        if self.speed[0]>0:
            self.image = self.oriImg["right"]
            canvas.addTrails( [4,6,8], [12,15,18], (200,120,80,220), getPos(self,0.1,0.4+random()*0.3) )
        elif self.speed[0]<0:
            self.image = self.oriImg["left"]
            canvas.addTrails( [4,6,8], [12,15,18], (200,120,80,220), getPos(self,0.9,0.4+random()*0.3) )
        self.mask = pygame.mask.from_surface(self.image)
        # adjust speed
        if not delay%8:
            my_ctr = getPos(self,0.5,0.5)
            tgt_ctr = getPos(self.tgt,0.5,0.5)
            if my_ctr[0]>tgt_ctr[0] and self.speed[0]>-self.fullSpd:
                self.speed[0] -= 1
            elif my_ctr[0]<tgt_ctr[0] and self.speed[0]<self.fullSpd:
                self.speed[0] += 1
            if my_ctr[1]>tgt_ctr[1] and self.speed[1]>-self.fullSpd:
                self.speed[1] -= 1
            elif my_ctr[1]<tgt_ctr[0] and self.speed[1]<self.fullSpd:
                self.speed[1] += 1
            # change push和rotation.
            if self.speed[0]>0:
                self.push = 9
            elif self.speed[0]<0:
                self.push = -9
            else:
                self.push = 0
            canvas.addTrails( [6, 7, 8], [10, 12, 14], (120,100,40,180), getPos(self,0.5,0.5) )
        if cldList(self, [self.tgt]):
            self.rect.left += self.speed[0]
            self.rect.top += self.speed[1]
            self._explode(canvas)
            return "vib"
        # move the object
        self.rect.left += self.speed[0]
        self.rect.top += self.speed[1]

    def _explode(self, canvas):
        self.blastSnd.play(0)
        canvas.addExplosion(getPos(self,0.5,0.5), 32, 16)
        canvas.addSmoke( 6, (4, 6, 8), 2, (2,2,2,240), getPos(self,0.5,0.5), 4 )
        self.kill()

    def drawHealth(self, surface):
        pass

    def stun(self, duration):
        pass

    def hitted(self, damage, pushed, dmgType):
        self.health -= damage

    def paint(self, surface):
        '''shadRect = self.rect.copy()
        shadRect.left -= 8
        surface.blit( generateShadow(self.image), shadRect )'''
        surface.blit( self.image, self.rect )

class Drip(InanimSprite):
    oriImg = {"left":None, "right":None}
    fullSpd = 11
    blastSnd = None
    launchSnd = None

    def __init__(self, pos, direction, tgt=None):
        if not Drip.oriImg["left"]:
            Drip.oriImg = { "left": load("image/stg6/drip.png").convert_alpha(),
                "right":flip(load("image/stg6/drip.png").convert_alpha(), True, False) }
            Drip.blastSnd = pygame.mixer.Sound("audio/wizard/hit.wav")
            Drip.launchSnd = pygame.mixer.Sound("audio/missle.wav")

        InanimSprite.__init__(self, "drip")
        #self.launchSnd.play(0)
        if direction=="right":      # 为方便角度计算，以x向右为正方向、y向上为正方向
            self.speed = [self.fullSpd, 0]
            self.push = 6
        else:
            self.speed = [-self.fullSpd, 0]
            self.push = -6
        self.image = self.oriImg[direction]
        self.rect = self.image.get_rect()
        self.rect.left = pos[0]-self.rect.width//2
        self.rect.top = pos[1]-self.rect.height//2
        self.mask = pygame.mask.from_surface(self.image)
        self.damage = NB["drip"]["damage"]
        self.health = NB["drip"]["health"]
        self.dmgType = "physical"
        self.coin = 0
        self.manner = NB["drip"]["manner"]
        self.bldColor = (40,10,10,240)
        self.active = False

    def update(self, delay, monsters, heroes, canvas):
        if self.active:
            if self.speed[0]>0:
                canvas.addTrails( [5], [12], (240,210,150,240), getPos(self,0.1,0.5) )
            elif self.speed[0]<0:
                canvas.addTrails( [5], [12], (240,210,150,240), getPos(self,0.9,0.5) )
            # adjust speed
            if not delay%8:
                my_ctr = getPos(self,0.5,0.5)
                if ( self.speed[0]>0 and my_ctr[0]>=canvas.rect.width+100 ) or ( self.speed[0]<0 and my_ctr[0]<=-100 ):
                    # lift one layer
                    self.rect.top -= 144
                    if self.rect.bottom<0:
                        self.kill()
                        return
                    self.speed[0] = -self.speed[0]
                    self.push = -self.push
                    if self.speed[0]>0:
                        self.image = self.oriImg["right"]
                    elif self.speed[0]<0:
                        self.image = self.oriImg["left"]
                        self.mask = pygame.mask.from_surface(self.image)
                #tgt_ctr = getPos(self.tgt,0.5,0.5)
                # if my_ctr[0]>tgt_ctr[0] and self.speed[0]>-self.fullSpd:
                #     self.speed[0] -= 1
                # elif my_ctr[0]<tgt_ctr[0] and self.speed[0]<self.fullSpd:
                #     self.speed[0] += 1
                # if my_ctr[1]>tgt_ctr[1] and self.speed[1]>-self.fullSpd:
                #     self.speed[1] -= 1
                # elif my_ctr[1]<tgt_ctr[0] and self.speed[1]<self.fullSpd:
                #     self.speed[1] += 1
            # move the object
            self.rect.left += self.speed[0]
            #self.rect.top += self.speed[1]
            # deal damage to all life
            if not delay%2:
                for group in [monsters, heroes]:
                    for each in group:
                        if each!=self and collide_mask( self, each ):
                            each.hitted( self.damage, self.push, self.dmgType )
                            self.blastSnd.play(0)

    def drawHealth(self, surface):
        pass

    def stun(self, duration):
        pass

    def hitted(self, damage, pushed, dmgType):
        if not self.active:
            self.active = True
            self.launchSnd.play(0)
        #self.health -= damage

    def paint(self, surface):
        '''shadRect = self.rect.copy()
        shadRect.left -= 8
        surface.blit( generateShadow(self.image), shadRect )'''
        surface.blit( self.image, self.rect )


# ========================================================================
# --------------------------------- CP 7 ---------------------------------
# ========================================================================
class Log(InanimSprite):
    fullSpd = 7

    def __init__(self, bg_size, layer, pos):
        InanimSprite.__init__(self, "log")
        self.imgList = { -1:[ load("image/stg7/log0.png").convert_alpha(), load("image/stg7/log1.png").convert_alpha() ],
            1:[flip(load("image/stg7/log0.png").convert_alpha(), True, False), flip(load("image/stg7/log1.png").convert_alpha(), True, False)] }
        self.speed = [ choice([-1,1]), randint(0,self.fullSpd) ]
        self.imgIndx = 0
        self.image = self.imgList[self.speed[0]][self.imgIndx]
        self.rect = self.image.get_rect()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect.left = pos[0]-self.rect.width//2
        self.rect.bottom = pos[1]
        self.onlayer = int(layer)
        self.bg_size = bg_size
        self.damage = NB["log"]["damage"]
        self.dmgType = "physical"
        self.hitSnd = pygame.mixer.Sound("audio/log.wav")
        
    def update(self, delay, sprites, groupList, keyline, boundaries, canvas):
        # 造成伤害
        if not delay%DMG_FREQ:
            for each in sprites:
                if collide_mask( self, each ):
                    if each.rect.left+each.rect.width//2 > self.rect.left+self.rect.width//2:
                        each.hitted(self.damage, 5, self.dmgType)
                    else:
                        each.hitted(self.damage, -5, self.dmgType)
        # 处理图片
        if not delay%6:
            self.imgIndx = (self.imgIndx+1) % len(self.imgList[1])
            self.image = self.imgList[self.speed[0]][self.imgIndx]
            self.speed[1] = min(self.speed[1]+1, self.fullSpd)
        # 移动位移
        self.rect.left += self.speed[0]
        self.rect.bottom += self.speed[1]
        canvas.addTrails( [1,2], [6,12,18], (40,80,40,160), getPos(self,choice([0.1,0.9]),0.5) )
        # 发生侧越界，横向改向
        if self.rect.left<boundaries[0] or self.rect.right>boundaries[1]:
            self.speed[0] = -self.speed[0]
        # 发生下碰撞，向上弹起
        if ( str(self.onlayer) in groupList ) and pygame.sprite.spritecollide(self, groupList[str(self.onlayer)], False, collide_mask):
            self.speed[1] = (-self.fullSpd+3)
            self.onlayer -= 2
            if self.rect.bottom>0 and self.rect.top<self.bg_size[1]:
                self.hitSnd.play(0)
                canvas.addPebbles( self, 4 )
                return "vib"
        # 碰撞或越线，发生其一即onlayer-2.
        elif self.rect.top >= keyline:
            self.onlayer -= 2
            if self.onlayer<0:
                canvas.addPebbles( self, 10, type="metalDebri" )
                self.kill()
                del self
                return "vib"

class Guard(Monster):
    imgLib = None
    shadLib = None
    snd = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        # calculate its position
        if not self.imgLib:
            Guard.imgLib = {
                "iList": createImgList("image/stg7/guard0.png","image/stg7/guard1.png","image/stg7/guard2.png","image/stg7/guard3.png"),
                "attList": createImgList("image/stg7/att0.png","image/stg7/att1.png","image/stg7/att0.png")
            }
            Guard.shadLib = getShadLib(Guard.imgLib)
            Guard.snd = pygame.mixer.Sound("audio/guardAtt.wav")

        Monster.__init__(self, "guard", (255,0,0,240), 6, 1, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left+wall.rect.width//2-self.rect.width//2
        self.rect.bottom = wall.rect.top
        self.alterSpeed( choice([-1,0,1]) )   # 0表示原地不动，负数表示向左移动，正数表示向右移动
        self.status = "wandering"          # wandering表示闲逛的状态，alarming表示发现英雄的状态
        # Define shield.
        self.shieldR = { "left":(0.2,0.62), "right":(0.8,0.62) }
        self.shieldImg = createImgList( "image/stg7/shield.png" )
        self.shield = Ajunction( self.shieldImg["left"][0], getPos(self, self.shieldR["left"][0], self.shieldR["left"][1]) )
        # Define spear.
        self.spearR = { "left":(0.15,0.6), "right":(0.85,0.6) }
        self.spearAttR = { "left":(0.08,0.65), "right":(0.92,0.65) }
        self.spearImg = createImgList( "image/stg7/spear.png" )
        self.spearAttImg = createImgList( "image/stg7/spearAtt.png" )
        self.spear = Ajunction( self.spearImg["left"][0], getPos(self, self.spearR["left"][0], self.spearR["left"][1]) )

    # 这个move()函数是供外界调动的接口，这里仅起根据传入的英雄参数判断状态的作用。判断完成后，修改自身的状态，然后执行相应的函数。
    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()

        if self.stun_time==0:
            for hero in sprites:
                # 如果有英雄在同一层，则将速度改为朝英雄方向。(这里的两套体系，英雄的层数为偶数，而怪物用的层数都是奇数)
                if ( (hero.onlayer-1)==self.onlayer and ( self.scope[0]<=getPos(hero,1,0.5)[0] ) and ( getPos(hero,0,0.5)[0]<=self.scope[1] ) ) or self.coolDown>0:
                    self.status = "alarming"
                    self.tgt = hero
                    break     # ***这里碰到第一个英雄符合条件就退出了。因此，如果两个英雄同时在一层中，P1总是会被针对，而P2永远不会被选中为目标。问题留着以后修正。
                else:
                    self.status = "wandering"
            if self.status == "wandering":
                self.wander( delay )
            elif self.status == "alarming":
                self.attack( sprites )
        self.checkImg(delay)

    def checkImg(self, delay):
        trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom ]
        # renew the image of the guard
        if self.coolDown==0:
            if self.speed and not (delay % 10 ):
                self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
            elif self.speed == 0:
                self.imgIndx = 0
            self.setImg("iList",self.imgIndx)
            self.spear.updateImg( self.spearImg[self.direction][0] )
            self.spear.updatePos( getPos(self, self.spearR[self.direction][0], self.spearR[self.direction][1]) )
        else:
            self.setImg("attList",self.coolDown // 13)
            self.spear.updateImg( self.spearAttImg[self.direction][0] )
            self.spear.updatePos( getPos(self, self.spearAttR[self.direction][0], self.spearAttR[self.direction][1]) )
        self.rect = self.image.get_rect()
        self.rect.left = trPos[0]-self.rect.width//2
        self.rect.bottom = trPos[1]
        # adjust shield and spear
        self.shield.updateImg( self.shieldImg[self.direction][0] )
        self.shield.updatePos( getPos(self, self.shieldR[self.direction][0], self.shieldR[self.direction][1]) )

    def wander(self, delay):
        if (self.speed):                          # speed!=0，在运动。
            self.rect.left += self.speed
            if (getPos(self, 0.7, 1)[0] >= self.scope[1] and self.speed > 0) or (getPos(self, 0.3, 1)[0] <= self.scope[0] and self.speed < 0):
                self.alterSpeed( -self.speed )
            if not delay % 20 and random()<0.08:  # 随机进入休息状态。
                self.alterSpeed( 0 )
                self.direction = "left" if random()<0.5 else "right"
        elif not delay % 20 and random()<0.08:    # 否则，在休息。此时若随机数满足条件，进入巡逻状态
            self.alterSpeed( choice( [1,-1] ) ) 
    
    def attack(self, sprites):
        if not self.coolDown:
            if getPos( self.tgt, 0.5, 0.5 )[0]>getPos( self, 0.5, 0.5 )[0]:
                self.alterSpeed(1)
            else:
                self.alterSpeed(-1)
        self.rect.left += self.speed * 2
        if self.coolDown==0:
            for each in sprites:
                if abs(getPos(self, 0.5, 0.5)[0]-getPos(each, 0.5, 0.5)[0])<40:
                    self.snd.play(0)    # 攻击英雄，咆哮
                    self.speed = 0
                    self.coolDown = 38
        else:
            self.coolDown -= 1
            if self.coolDown == 20:
                for each in sprites:
                    if collide_mask(self.spear, each):
                        cldList( self, sprites )
    
    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.coolDown = 0
        self.tgt = None         # 指示要攻击的英雄

    def paint(self, screen):
        # 画阴影
        shadRect = self.rect.copy()
        shadRect.left -= self.shadOffset
        screen.blit(self.shad, shadRect)
        screen.blit( self.spear.image, self.spear.rect )
        screen.blit( self.image, self.rect )
        screen.blit( self.shield.image, self.shield.rect )
        # 画打击阴影
        if self.hitBack:
            screen.blit( self.shad, self.rect )
    
    def level(self, dist):
        self.rect.left += dist
        self.spear.rect.left += dist
        self.shield.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)
    
    def hitted(self, damage, pushed, dmgType):
        if pushed>0:   # 向右击退
            self.hitBack = max( pushed-self.weight, 0 )
        elif pushed<0: # 向左击退
            self.hitBack = min( pushed+self.weight, 0 )
        self.bldColor = (255,0,0,240)
        if ( pushed<0 and self.direction=="right" ) or ( pushed>0 and self.direction=="left"):
            self.bldColor = (200,200,200,240)
            damage = round(damage*self.realDmgRate)       # 原来的20%
        self.health -= damage
        self.msgList.append( [getPos(self,0.5,0.5), str(damage), 60] )
        if self.health <= 0:       # dead
            self.health = 0
            self.kill()
            return True

# -----------------------------------
class Flamen(Monster):
    imgLib = None
    shadLib = None
    snd = None

    def __init__(self, wallGroup, sideGroup, blockSize, onlayer):
        # calculate its position
        if not self.imgLib:
            Flamen.imgLib = {
                "iList": createImgList("image/stg7/flamen0.png","image/stg7/flamen1.png"),
                "attList": createImgList("image/stg7/flamenAtt0.png","image/stg7/flamenAtt1.png")
            }
            Flamen.shadLib = getShadLib(Flamen.imgLib)
            Flamen.snd = pygame.mixer.Sound("audio/flamenSummon.wav")

        Monster.__init__(self, "flamen", (255,0,0,240), 0, 1, onlayer, sideGroup)
        wall = self.initLayer(wallGroup, sideGroup)
        # initialize the sprite
        self.reset()
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        self.rect.left = wall.rect.left+wall.rect.width//2-self.rect.width//2
        self.rect.bottom = wall.rect.top-10
        self.alterSpeed( choice([-1,0,1]) )   # 0表示原地不动，负数表示向左移动，正数表示向右移动
        self.upDown = 2               # 悬停状态身体上下振幅

    # 这个move()函数是供外界调动的接口，这里仅起根据传入的英雄参数判断状态的作用。判断完成后，修改自身的状态，然后执行相应的函数。
    def move(self, delay, sprites):
        self.checkHitBack(obstacle=True)
        self.count_stun()

        if not (delay % 24):
            self.rect.top += self.upDown
            self.upDown = -self.upDown
        if self.stun_time==0:
            self.coolDown -= 1
            # renew the image of the flamen
            trPos = [ self.rect.left + self.rect.width//2, self.rect.bottom - self.rect.height//2 ]
            if self.coolDown>100:
                if not (delay % 20 ):
                    self.imgIndx = (self.imgIndx+1) % len(self.imgLib["iList"]["left"])
                self.setImg("iList",self.imgIndx)
            elif self.coolDown==100 or self.coolDown==10:
                self.setImg("attList",0)
            elif self.coolDown==90:
                self.setImg("attList", 1)
            self.rect = self.image.get_rect()
            self.rect.left = trPos[0]-self.rect.width//2
            self.rect.bottom = trPos[1]+self.rect.height//2

            if self.coolDown<=0:
                self.chargeList.clear()
                self.coolDown = randint(300,660)
            elif self.coolDown>100:                       # 根据coolDown决定标记英雄进行攻击或游荡。
                if (self.speed):                          # speed!=0，在运动。
                    if not (delay%2):
                        self.rect.left += self.speed
                        if (getPos(self, 0.7, 1)[0] >= self.scope[1] and self.speed > 0) or (getPos(self, 0.3, 1)[0] <= self.scope[0] and self.speed < 0):
                            self.alterSpeed( -self.speed )
                    if not delay % 20 and random()<0.08:  # 随机进入休息状态。
                        self.alterSpeed( 0 )
                        self.direction = "left" if random()<0.5 else "right"
                elif not delay % 20 and random()<0.08:    # 否则，在休息。此时若随机数满足条件，进入游荡状态
                    self.alterSpeed( choice( [1,-1] ) ) 
            elif self.coolDown==100:
                self.tgt = choice(sprites)
                self.ctr = getPos(self.tgt, 0.5, -1)
                self.snd.play(0)
                self.alterSpeed(0)
                return SoulBlast(self.ctr, self.tgt.onlayer-1, 60)
    
    def reset(self):
        self.imgIndx = 0
        self.setImg("iList",0)
        self.coolDown = 300
        self.ctr = [0,0]
        self.tgt = None         # 指示要攻击的英雄
        self.chargeList = []

    def level(self, dist):
        self.rect.left += dist
        self.scope = (self.scope[0]+dist, self.scope[1]+dist)
    
    def lift(self, dist):
        self.rect.bottom += dist
        self.ctr[1] += dist
    
class SoulBlast(InanimSprite):
    
    def __init__(self, pos, layer, cnt):
        InanimSprite.__init__(self, "soulBlast")
        self.imgList = [load("image/stg7/soulBlast0.png").convert_alpha(), load("image/stg7/soulBlast1.png").convert_alpha()]
        self.image = self.imgList[0]
        self.imgIndx = 0
        self.rect = self.image.get_rect()
        self.rect.left = pos[0]-self.rect.width//2
        self.rect.bottom = pos[1]+self.rect.height//2
        self.mask = pygame.mask.from_surface(self.image)
        self.damage = MB["flamen"].damage
        self.dmgType = MB["flamen"].dmgType
        self.onlayer = int(layer)
        self.push = 0

        self.ctr = pos
        self.cnt = cnt      # 预警倒计时
        self.chargeList = []
        self.snd = pygame.mixer.Sound("audio/priest/hit.wav")
    
    def update(self, delay, sideWalls, downWalls, keyLine, sprites, canvas, bg_size):
        # 蓄力阶段
        if self.cnt>0:
            self.cnt -= 1
            if random()<0.3:      # 某概率添加新粒子
                r = choice( [3,4,5] )
                XRange = list( range(self.ctr[0]-50,self.ctr[0]-30) ) + list( range(self.ctr[0]+30,self.ctr[0]+50) )
                YRange = list( range(self.ctr[1]-50,self.ctr[1]-30) ) + list( range(self.ctr[1]+30,self.ctr[1]+50) )
                pos = [ choice( XRange ), choice( YRange ) ]
                color = choice( [(210,255,210,240),(170,255,170,240),(110,150,110,240)] )
                self.chargeList.append( (r, pos, color) )
        # 下落阶段
        else:
            self.rect.bottom += 4
            canvas.addTrails( [3,5,7], [18,20,24], (20,220,60,240), getPos(self, 0.3+random()*0.4, 0.3+random()*0.4) )
            if not delay%(DMG_FREQ//2):
                if cldList( self, sprites ):      # 命中英雄
                    self._explode(canvas)
                self.imgIndx = (self.imgIndx+1) % len(self.imgList)
                self.image = self.imgList[self.imgIndx]
            if pygame.sprite.spritecollide(self, downWalls, False, collide_mask):
                self._explode(canvas)
                self.kill()
                del self
                return
            else:
                # 只有下方的sideWall会被撞击爆炸
                for each in pygame.sprite.spritecollide(self, sideWalls, False, collide_mask):
                    if each.category=="sideWall" and each.coord[1]<=self.onlayer:
                        self._explode(canvas)
                        self.kill()
                        del self
                        return
            if ( self.rect.top >= keyLine ):    # 只有大于检查，因此只有初始行之下的砖块会与之碰撞
                self.onlayer = max(self.onlayer-2, -1)

    def _explode(self, canvas):
        self.snd.play(0)
        canvas.addWaves( getPos(self, 0.5, 0.5), (60,240,80,240), 30, 15 )
    
    def paint(self, surface):
        if self.cnt>0:
            for each in self.chargeList:  # 绘制并移动粒子
                pygame.draw.circle( surface, each[2], each[1], each[0] )  # 充能粒子
                each[1][0] += (self.ctr[0]-each[1][0]) // 8
                each[1][1] += (self.ctr[1]-each[1][1]) // 8
            pygame.draw.circle( surface, (100,240,100), self.ctr, min(60-self.cnt, 30) )   # 聚能中心
        else:
            surface.blit( self.image, self.rect )

# -----------------------------------
class Assassin(Monster):
    imgLib = None
    shadLib = None
    dashSnd = None
    cldSnd = None

    def __init__(self, XRange, y, onlayer, sideGroup):
        # calculate its position
        if not self.imgLib:
            Assassin.imgLib = {
                "wait": createImgList("image/stg7/assassin0.png"),
                "prepare": createImgList("image/stg7/assassin1.png"),
                "dash": createImgList("image/stg7/assassinAtt.png")
            }
            Assassin.shadLib = getShadLib(Assassin.imgLib)
            Assassin.dashSnd = pygame.mixer.Sound("audio/assassinDash.wav")
            Assassin.cldSnd = pygame.mixer.Sound("audio/assassinCld.wav")
        
        # Search both sidewalls of the given layer
        layerwall = []
        while True:
            for sideWall in sideGroup:
                if sideWall.coord[1] == int(onlayer):
                    layerwall.append(sideWall)
            # when layerwall is empty, adjust the layer to lower level and find again
            # (will finally find one because the lowest 10 layers surely have )
            if layerwall:
                break
            else:
                onlayer = int(onlayer)-2
        wall = choice(layerwall)
        self.XRange = XRange
        Monster.__init__(self, "assassin", (250,0,0,240), 4, 1, onlayer, sideGroup)

        # initialize the sprite
        self._reset()
        self.setImg(self.status,0)
        self.mask = pygame.mask.from_surface(self.image)
        self.rect = self.image.get_rect()
        if wall.coord[0] == 0:  # left side wall
            self.direction = "right"
            self.rect.left = wall.rect.right
        else:
            self.direction = "left"
            self.rect.right = wall.rect.left
        self.rect.bottom = wall.rect.bottom-4
        self.dashSpd = 10
        self.tgt = None
        self.rectList = []  # stack

    def move(self, delay, sprites, YRange, spurtCanvas):
        self.checkHitBack(obstacle=True)

        self.setImg(self.status)
        if self.status == "wait":
            if len(self.rectList)>0:
                self.rectList.pop(0)
            # going to prepare mode
            self.coolDown -= 1
            if self.coolDown == 0:
                self.status = "prepare"
                self.coolDown = 38
                # find tgt and determine speed
                self.tgt = choice(sprites)
                ctr_a = getPos(self.tgt)
                ctr_b = getPos(self)
                # determine x speed
                if self.direction == "right":
                    self.speed[0] = self.dashSpd
                    self.push = self.pushList[1]
                else:
                    self.speed[0] = -self.dashSpd
                    self.push = self.pushList[0]
                # Draft a y speed according to hero's position
                time1 = round( abs(ctr_a[0]-ctr_b[0]) / self.dashSpd )
                if time1==0:
                    time1 = 1
                self.speed[1] = round( (ctr_a[1]-ctr_b[1]) / time1 )
                # Adjust y speed to reasonable range
                time2 = (self.XRange[1]-self.XRange[0]) / self.dashSpd
                # y速度压缩到[-6, 6]
                if self.speed[1]>6:
                    self.speed[1] = 6
                elif self.speed[1]<-6:
                    self.speed[1] = -6
                # 保证竖直位移不超出范围，否则循环调整。NOTE：YRange[0]是塔楼最低，但像素值最大
                while not ( YRange[1]+80 < ctr_b[1] + time2*self.speed[1] < YRange[0]-80 ): 
                    if self.speed[1] > 0:
                        self.speed[1] -= 1
                    elif self.speed[1] < 0:
                        self.speed[1] += 1
                    else:
                        break
        elif self.status == "prepare":
            # going to dash mode
            self.coolDown -= 1
            if self.coolDown == 0:
                self.dashSnd.play(0)
                self.status = "dash"
                spurtCanvas.addSpatters( 6, [2,3,4], [10,11,12], (240,240,240), getPos(self,0.5,0.6) )
        else:
            # DASHING: add shad
            spurtCanvas.addTrails( [1,2,3], [18,20,22], (240,240,240), getPos(self, 0.5, 0.5) )
            self.rectList.append(self.rect.copy())
            if len(self.rectList)>6:
                self.rectList.pop(0)
            # move
            self.rect.left += self.speed[0]
            self.rect.top += self.speed[1]
            # when dashing, check collision with hero.
            if not delay%DMG_FREQ:
                cldList( self, sprites )
            # check stop.
            if (self.direction=="left" and self.rect.left<self.XRange[0]) or (self.direction=="right" and self.rect.right>self.XRange[1]):
                self.cldSnd.play(0)
                if self.direction=="right":
                    self.direction = "left"
                    self.rect.right = self.XRange[1]
                    spurtCanvas.addSpatters( 8, [2,3,4], [10,11,12], (240,240,240), getPos(self,1,0.6) )
                else:
                    self.direction = "right"
                    self.rect.left = self.XRange[0]
                    spurtCanvas.addSpatters( 8, [2,3,4], [10,11,12], (240,240,240), getPos(self,0,0.6) )
                self._reset()
    
    def _reset(self):
        self.status = "wait"    # wait, prepare, dash
        self.speed = [0,0]
        self.coolDown = randint(20,120)
        
    def stun(self, duration):
        pass

    def paint(self, surface):
        # 画残影
        for rect in self.rectList:
            surface.blit(self.shad, rect)
        # 画阴影
        shadRect = self.rect.copy()
        shadRect.left -= self.shadOffset
        surface.blit(self.shad, shadRect)
        surface.blit( self.image, self.rect )
        # 画打击阴影
        if self.hitBack:
            surface.blit( self.shad, self.rect )

    def level(self, dist):
        self.rect.left += dist
        self.XRange = (self.XRange[0]+dist, self.XRange[1]+dist)

# Boss ------------------------------
class Chicheng(Boss):

    def __init__(self, groupList, onlayer, font):
        # initialize the sprite
        Boss.__init__(self, font, "Chicheng", (255,0,0,240), 6, 4, onlayer, shadOffset=12)
        self.initLayer(groupList)
        self.imgLib = {
            "body": createImgList("image/stg7/ccBody.png"),
            "jump": createImgList("image/stg7/ccJump.png"),
            "knock": createImgList("image/stg7/ccKnock.png")
        }
        self.shadLib = getShadLib(self.imgLib)
        # ----- body part (the core of General Chicheng) ------
        self.setImg("body")
        self.mask = pygame.mask.from_surface(self.image)
        # calculate its position
        self.rect = self.image.get_rect()
        self.rect.left = self.initPos[0]-self.rect.width//2
        self.rect.bottom = self.initPos[1]          
        self.alterSpeed( choice( [-1, 1] ) )
        # ------------- Cloak part ----------------
        self.cloakLeft = [ load("image/stg7/ccCloak0.png").convert_alpha(), load("image/stg7/ccCloak1.png").convert_alpha() ]
        self.cloakRight = [ flip(self.cloakLeft[0], True, False), flip(self.cloakLeft[1], True, False) ]
        self.cloakR = { "left":[ (0.7,0.64), (0.7,0.64) ], "right":[ (0.3,0.64), (0.3,0.64) ] }
        self.cloak = Ajunction( self.cloakLeft[0], getPos(self, self.cloakR[self.direction][0][0], self.cloakR[self.direction][0][1]) )
        self.cloakIndx = 0
        # -------------- weapon part ---------------
        self.weaponLeft = [ load("image/stg7/ccWeapon.png").convert_alpha(), load("image/stg7/ccWeaponJump.png").convert_alpha(), load("image/stg7/ccWeapon.png").convert_alpha() ]
        self.weaponRight = [ flip(self.weaponLeft[0], True, False), flip(self.weaponLeft[1], True, False), flip(self.weaponLeft[2], True, False) ]
        self.weaponR = { "left":[ (0.3,0.84), (0.7,0.4), (0,0.86) ], "right":[ (0.7,0.84), (0.3,0.4), (1,0.86) ] }
        self.weapon = Ajunction( self.weaponLeft[0], getPos(self, self.weaponR[self.direction][0][0], self.weaponR[self.direction][0][1]) )
        self.weaponIndx = 0
        self.weapon.damage = self.damage
        self.weapon.dmgType = self.dmgType
        self.weapon.push = self.push
        # ----------- other attributes -------------------------
        self.cnt = 300      # count for the loop of shift position
        self.reset()
        self.knockCnt = 0
        self.dealt = False
        self.mockSnd = pygame.mixer.Sound("audio/chichengMock.wav")
        self.knockSnd = pygame.mixer.Sound("audio/chichengKnock.wav")
        self.threatSnd1 = pygame.mixer.Sound("audio/ccSilent.wav")
        self.jumping = False
        self.max_spd = 6
        # ---------- silent particle --------------------------
        # [pos, speed, tgtRect, tgthero]
        self.parti = None

    def move(self, sprites, canvas, groupList, knock, GRAVITY):
        self.checkHitBack()
        self._tipPosition(canvas)
        self.count_stun()

        # when knockcnt>0, dealing damage
        if self.knockCnt>0:
            self.knockCnt -= 1
            if not self.dealt:
                if cldList(self, sprites) or cldList(self.weapon, sprites):
                    self.dealt = True
        else:
            # knockCnt = 0的情况，可能的状态有很多
            if knock:         # 刚刚落地瞬间，deal damage
                self.setImg("knock")
                self.weaponIndx = 2
                self.knockCnt = 18
                self.dealt = False
                self.push = self.pushList[0] if self.direction=="left" else self.pushList[1]
                for i in (0.1,0.4,0.6,0.9):
                    canvas.addSpatters(randint(2,6), [4,6,8], [28,32,36], (40,30,30,200), getPos(self, i, 0.9), False)
            elif self.combo>0 and not self.jumping:
                self.takeOff(sprites, groupList, GRAVITY)
                self.combo -= 1
            elif self.jumping:    # 跳跃中
                self.setImg("jump")
                self.weaponIndx = 1
            else:       # 落地完成,正常态
                self.setImg("body")
                self.weaponIndx = 0
                if self.stun_time==0:
                    # Randomly implement silent paritcle
                    if not self.parti and not self.cnt%5 and random()<0.05:
                        self.threatSnd1.play(0)
                        tgts = [hero for hero in sprites if hero.category=="hero"]
                        tgt_hero = choice(tgts)
                        rect = tgt_hero.slot.slotDic["brand"][1]
                        startPos = getPos(self,0.5,0.5)
                        finalPos = [rect.left+rect.width//2, rect.top+rect.height//2]
                        speedX = round( (finalPos[0] - startPos[0]) / 40 )
                        speedY = round( (finalPos[1] - startPos[1]) / 40 )
                        self.parti = [startPos, (speedX, speedY), rect, tgt_hero]
        # about updating images.
        if not (self.cnt % 2):
            # 身体红光
            canvas.addSmoke( 1, (2,4,6), 5, (180,20,20,180), getPos(self,0.5,random()), 60 )
            # 眼睛的光
            for i in (0.4,0.6):
                canvas.addSmoke( 1, (2,4,6), 6, (180,180,20,180), getPos(self,i,0.3), 5, speed=[0,0] )
            if self.direction == "left":
                self.cloak.updateImg( self.cloakLeft[self.cloakIndx] )
                self.weapon.updateImg( self.weaponLeft[self.weaponIndx] )
            elif self.direction == "right":
                self.cloak.updateImg( self.cloakRight[self.cloakIndx] )
                self.weapon.updateImg( self.weaponRight[self.weaponIndx] )
            self.mask = pygame.mask.from_surface(self.image)
            if not self.cnt%6:
                self.cloakIndx = (self.cloakIndx+1) % len(self.cloakLeft)
        self.cloak.updatePos( getPos(self, self.cloakR[self.direction][self.cloakIndx][0], self.cloakR[self.direction][self.cloakIndx][1]) )
        self.weapon.updatePos( getPos(self, self.weaponR[self.direction][self.weaponIndx][0], self.weaponR[self.direction][self.weaponIndx][1]) )
        # count down for rage actions.
        self.cnt -= 1
        if self.cnt<=0:
            self.cnt = randint(300,320)
        if self.jumping:
            self.rect.left += self.speed    # Only consider x here. y is acted by fall()
        elif not self.jumping and self.cnt==240:
            if self.stun_time==0:
                self.takeOff(sprites, groupList, GRAVITY)
                self.combo = randint(2,4)
        # move particle if there is one
        if self.parti:
            pos, speed, rect, hero = self.parti
            self.parti[0] = (pos[0]+speed[0], pos[1]+speed[1])
            canvas.addTrails( [1,2,3], [14,16,18], (190,30,30,210), self.parti[0] )
            if (rect.left<=self.parti[0][0]<=rect.right) and (rect.top<=self.parti[0][1]<=rect.bottom):
                canvas.addExplosion( [rect.left+rect.width//2, rect.top+rect.height//2], 30, 16, waveColor=(190,30,30,210), spatColor=(190,190,40) )
                hero.arrow = 0
                hero.loading = 0
                del self.parti
                self.parti = None

    def takeOff(self, sprites, groupList, GRAVITY):
        if random()<0.8:
            self.mockSnd.play(0)
        tgt = choice(sprites)
        self.jumping = True
        tgtPos, myPos = getPos(tgt,0.5,1), getPos(self,0.5,1)
        # 目标在下方或同行
        if tgt.onlayer-1<=self.onlayer:
            self.onlayer = tgt.onlayer-1
            self.gravity = -14
            self.alarmTime = self.estimateTime(14, tgtPos[1]-myPos[1], GRAVITY)
        # 否则目标在上方
        else:
            if (str(self.onlayer+2) in groupList):
                # need to confirm that new layer is in groupList (in case of hero jump to the highest layer)
                self.onlayer += 2
            self.gravity = -18
            self.alarmTime = self.estimateTime(18, tgtPos[1]-myPos[1], GRAVITY)
        self.initLayer(groupList)
        x_spd = round( (tgtPos[0]-myPos[0])/self.alarmTime )
        if x_spd<-self.max_spd:
            x_spd = -self.max_spd
        elif x_spd>self.max_spd:
            x_spd = self.max_spd
        self.alterSpeed( x_spd )

    def estimateTime(self, upwardSpd, absVertical, GRAVITY):
        absDistY = 0
        for y in range(upwardSpd+1):     # 计算得上升总高度(此过程用时upwardSod减至0)
            absDistY += y
        downY = abs(absVertical) + absDistY  # 下降总位移
        anaSpd = 0
        estTime = upwardSpd
        while downY>0:
            absDistY += anaSpd
            downY -= anaSpd
            anaSpd = min(anaSpd+1, GRAVITY)
            estTime += 1
        return estTime

    def fall(self, keyLine, groupList, GRAVITY):
        if self.gravity<GRAVITY:
            self.gravity += 1
        self.rect.bottom += self.gravity
        if self.gravity<0:      # Still in upward action, don't check fall!
            return
        while ( pygame.sprite.spritecollide(self, self.wallList, False, collide_mask) ):  # 如果和参数中的物体相撞，则尝试纵坐标-1
            self.rect.bottom -= 1
            self.gravity = 0
            if self.jumping:
                self.knockSnd.play(0)
                self.jumping = False
                return "vib"
        if getPos(self, 0, 0.5)[1] > keyLine:
            self.onlayer  = max(self.onlayer-2, -1)
            self.initLayer( groupList )
            # 更新obstacle砖块
            self.renewObstacle(groupList["0"])
                
    def paint(self, screen):
        '''鉴于本对象的构造非常复杂，因此提供一个专门的绘制接口
            给此函数传递一个surface参数，即可在该surface上绘制（blit）完整的本对象'''
        # 画阴影
        shadRect = self.rect.copy()
        shadRect.left -= self.shadOffset
        screen.blit(self.shad, shadRect)
        # 画本身
        screen.blit( self.weapon.image, self.weapon.rect )
        screen.blit( self.cloak.image, self.cloak.rect )
        screen.blit( self.image, self.rect )
        # 画打击阴影
        if self.hitBack:
            screen.blit( self.shad, self.rect )
        # draw particle 
        if self.parti:
            pygame.draw.circle(screen, (190,30,30), self.parti[0], randint(6,8))
       
    def reset(self):
        self.alarmTime = 0
        self.combo = 0

    def erase(self):
        self.mockSnd.play(0)
        self.weapon.kill()
        self.cloak.kill()
        del self.weapon, self.cloak
        self.kill()