71 lines
1.4 KiB
HLSL
71 lines
1.4 KiB
HLSL
// Copyright Epic Games, Inc. All Rights Reserved.
|
|
|
|
#include "../Common.ush"
|
|
|
|
|
|
//------------------------------------------------------- CONSTANTS
|
|
|
|
#define TILE_SIZE 8
|
|
|
|
|
|
//------------------------------------------------------- PARAMETERS
|
|
|
|
uint2 FilmGrainTextureSize;
|
|
Texture2D FilmGrainTexture;
|
|
|
|
RWTexture2D<float4> Output;
|
|
|
|
|
|
//------------------------------------------------------- LDS
|
|
|
|
groupshared float4 SharedColor[TILE_SIZE * TILE_SIZE];
|
|
|
|
|
|
//------------------------------------------------------- ENTRY POINT
|
|
|
|
[numthreads(TILE_SIZE, TILE_SIZE, 1)]
|
|
void MainCS(
|
|
uint2 GroupId : SV_GroupID,
|
|
uint GroupThreadIndex : SV_GroupIndex)
|
|
{
|
|
uint2 InputPixelPos = TILE_SIZE * GroupId + uint2(GroupThreadIndex % TILE_SIZE, GroupThreadIndex / TILE_SIZE);
|
|
|
|
// Init LDS
|
|
float4 TexelColor = FilmGrainTexture[InputPixelPos];
|
|
{
|
|
bool bValidPixel = all(InputPixelPos < FilmGrainTextureSize);
|
|
|
|
if (!bValidPixel)
|
|
{
|
|
TexelColor = 0.0;
|
|
}
|
|
|
|
SharedColor[GroupThreadIndex] = TexelColor;
|
|
}
|
|
|
|
GroupMemoryBarrierWithGroupSync();
|
|
|
|
// Reduction
|
|
{
|
|
UNROLL
|
|
for (uint i = 32; i > 1; i /= 2)
|
|
{
|
|
TexelColor += SharedColor[GroupThreadIndex ^ i];
|
|
|
|
GroupMemoryBarrierWithGroupSync();
|
|
|
|
SharedColor[GroupThreadIndex] = TexelColor;
|
|
|
|
GroupMemoryBarrierWithGroupSync();
|
|
}
|
|
|
|
TexelColor += SharedColor[GroupThreadIndex ^ 0x1];
|
|
}
|
|
|
|
// Output
|
|
if (GroupThreadIndex == 0)
|
|
{
|
|
Output[GroupId] = TexelColor;
|
|
}
|
|
}
|