UnrealEngineUWP/Engine/Shaders/Private/RayTracing/VisualizeSkyLightMipTreePS.usf

// Copyright Epic Games, Inc. All Rights Reserved.

/*=============================================================================================
	VisualizeSkyLightMipTreePixelShader.usf: Interactive visualization of sky light mip tree.
===============================================================================================*/

#include "../Common.ush"
#include "MipTreeCommon.ush"

uint3 Dimensions;
Buffer<float> MipTreePosX;
Buffer<float> MipTreeNegX;
Buffer<float> MipTreePosY;
Buffer<float> MipTreeNegY;
Buffer<float> MipTreePosZ;
Buffer<float> MipTreeNegZ;

float SampleMipTree(uint FaceIndex, uint BufferOffset)
{
	float Value = 0.0;
	if (FaceIndex == 0)
	{
		Value = MipTreePosX[BufferOffset];
	}
	else if (FaceIndex == 1)
	{
		Value = MipTreeNegX[BufferOffset];
	}
	else if (FaceIndex == 2)
	{
		Value = MipTreePosY[BufferOffset];
	}
	else if (FaceIndex == 3)
	{
		Value = MipTreeNegY[BufferOffset];
	}
	else if (FaceIndex == 4)
	{
		Value = MipTreePosZ[BufferOffset];
	}
	else
	{
		Value = MipTreeNegZ[BufferOffset];
	}

	return Value;
}

void VisualizeSkyLightMipTreePS(
	in noperspective float2 UV : TEXCOORD0,
	out float4 OutColor : SV_Target0,
	out float OutMipTree : SV_Target1
)
{
	uint FaceIndex = 0;
	uint MipLevel = 0;
	uint2 TexCoord = UV * DimensionsAtLevel(Dimensions, MipLevel);
	uint BufferOffset = BufferOffsetAtPixel(TexCoord, MipLevel, Dimensions);

	OutColor = 0.f;
	OutMipTree = SampleMipTree(FaceIndex, BufferOffset);
}