RGB/UINT10 HDR Format not using ST.2084

Specification here: [Link Removed]

Which is mirrored in engine in FD3D12DynamicRHI::Init (for example):

[Image Removed]

However, FWindowsPlatformMisc::ChooseHDRDeviceAndColorGamut always returns 5 or 6, when it should be returning 3 or 4. Issue also seems to be present in the Mac version of the function too.

See licensee UDN for more info.

Enable HDR in windows/for your monitor.

In any project, add the following to DefaultEngine.ini:

[/Script/Engine.RendererSettings]
r.AllowHDR=1
r.HDR.EnableHDROutput=1

[/Script/WindowsTargetPlatform.WindowsTargetSettings]
DefaultGraphicsRHI=DefaultGraphicsRHI_DX12

BuildCookRun the project for Win64 (or launch via editor). Once built/cooked, launch the game from VisualStudio instead (-onethread helps a bit here too).

Set a breakpoint in FD3D12Viewport::EnsureColorSpace

Expected: DF_ACES1000_ST_2084 or DF_ACES2000_ST_2084 should be used

Result: DF_ACES1000_ScRGB:DF_ACES1000_ScRGB: or DF_ACES2000_ScRGB are used instead