Adds a function to Unreal that will retrieve the HDR calibration on Windows platforms for displays that have used the Windows 11 HDR calibration tool.
Function GetPrimaryDisplayInformation() (can be used in BP) will retrieve:
- The display name
- Min luminance
- Max luminance
- Max full-frame luminance
An ideal use-case for this is as the default values for HDR output, for users that have calibrated their HDR output in Windows 11. It will not return useful values on non-windows platforms, on < Win 11 platforms on Win 11 without HDR calibration.
To check if the values are usable, simply check if the MaxFullFrameLuminance or Maxluminance == 0. Note that this does not check for HDR support, as Unreal can already do that.
To set the HDR output nits, use EnableHDRDisplayOutput and use CVar r.HDR.Display.MaxLuminance. Setting the DisplayNits with EnableHDRDisplayOutput() does not actually change the output nits, just sets the property in UGameUserSettings.
I would also recommend allowing the user to override these values and ensuring that your game outputs the correct values. You can profile your HDR output on an HDR display with Reshade by using Lilium's HDR and SDR analysus (HDR analysis effect).