feat: gamma functionality on windows64

4J_Render/Windows64/shaders/build.bat

@@ -21,4 +21,5 @@ if not exist %OUT% mkdir %OUT%
 %FXC% %OPT% /T ps_4_0 /E main /D TEXTURE_PROJECTION /Fh %OUT%/PS_TextureProjection.h          /Vn g_main_PS_TextureProjection                 main_PS.hlsl
 %FXC% %OPT% /T ps_4_0 /E main /D FORCE_LOD   /Fh %OUT%/PS_ForceLOD.h                          /Vn g_main_PS_ForceLOD                          main_PS.hlsl
 %FXC% %OPT% /T ps_4_0 /E PS_ScreenSpace      /Fh %OUT%/PS_ScreenSpace.h                       /Vn g_main_PS_ScreenSpace                       screen_PS.hlsl
-%FXC% %OPT% /T ps_4_0 /E PS_ScreenClear      /Fh %OUT%/PS_ScreenClear.h                       /Vn g_main_PS_ScreenClear                       screen_PS.hlsl
+%FXC% %OPT% /T ps_4_0 /E PS_ScreenClear      /Fh %OUT%/PS_ScreenClear.h                       /Vn g_main_PS_ScreenClear                       screen_PS.hlsl
+%FXC% %OPT% /T ps_4_0 /E PS_ScreenGamma      /Fh %OUT%/PS_ScreenGamma.h                       /Vn g_main_PS_ScreenGamma                       screen_PS.hlsl

4J_Render/Windows64/shaders/screen_PS.hlsl

@@ -26,6 +26,11 @@ cbuffer cbuff : register(b4)
     float4 clearColour;
 };
 
+cbuffer gammaBuff : register(b6)
+{
+    float4 gammaParams;
+};
+
 SamplerState screen_sampler_s : register(s0);
 Texture2D<float4> screen_texture : register(t0);
 
@@ -37,4 +42,12 @@ float4 PS_ScreenSpace(float4 position : SV_POSITION, float2 texcoord : TEXCOORD0
 float4 PS_ScreenClear(float4 position : SV_POSITION) : SV_TARGET
 {
     return clearColour;
+}
+
+float4 PS_ScreenGamma(float4 position : SV_POSITION, float2 texcoord : TEXCOORD0) : SV_TARGET
+{
+    float4 colour = screen_texture.Sample(screen_sampler_s, texcoord);
+    float invGamma = gammaParams.x;
+    colour.rgb = pow(saturate(colour.rgb), invGamma);
+    return colour;
 }