ShaderModification

Veil adds a custom "scripting language" for injecting into shader sources. This system is intended to adding small hooks to vanilla shaders to make changes without replacing the entire file.

Defining Modifications

Shader modifications are loaded before any shaders are loaded. They are located in assets/modid/pinwheel/shader_modifiers/shaderid/path/to/shader/filename.vsh.txt. For example, a modification for minecraft:shaders/core/rendertype_solid.vsh would be located at assets/modid/pinwheel/shader_modifiers/minecraft/shaders/core/rendertype_solid.vsh.txt

This system allows a shader modifier to modify any shader, including pinwheel shaders. Pinwheel shader modification works exactly like vanilla shader modification.

Format

The basic syntax is as follows:

#version 330 // required
#priority 1000 // default 1000
#include veil:camera // Test include

// Replaces this with the defined shader
// #replace veil:shader/test

// Vertex Only
[GET_ATTRIBUTE 0] vec3 InPos; // test
[GET_ATTRIBUTE 4] vec3 Nom;

[OUTPUT] // Outputs are guaranteed to be unique
out vec4 Test;
out vec3 TestNormal;

[UNIFORM]
uniform sampler2D Sampler8;

[FUNCTION main(0) HEAD]
TestNormal = #Nom;
Test = vec4(#InPos, 1.0);

Header

#version specifies the minimum shader version for this modification. If unsure, use the version in the shader being modified.

#priority is used to determine the order modifications are loaded in. Modifications with a lower priority will load before others.

#include includes another file as specified in Shader Includes

#replace is a special option that replaces the targeted shader with another veil shader. This causes all other modifications to be ignored and should only be used as a last resort.

Commands

Commands can be added in any order and define where to inject shader code.

• [GET_ATTRIBUTE #] type name; Retrieves the specified attribute by id and assigns it to the specified alias for this modification. If the attribute doesn't exist it will be added. #name can be used anywhere in the file to use that attribute.
• [OUTPUT] Adds all code following as input variables. An input is automatically added to the next shader in the pipeline.
• [UNIFORM] Adds all following code at the end of the uniforms block.
• [FUNCTION name(params) location] Adds all following code into the specified method at the HEAD or TAIL

Functions

This directive specifies what method to inject into. The number of params is optional and is used to specify exactly what method to inject into. If not specified, all methods with the same name are matched.

The last option determines where to inject in the method. HEAD adds code before the method contents and TAIL adds code after the method contents.