Files
UnrealEngine/Engine/Shaders/Private/PostProcessBloom.usf
2025-05-18 13:04:45 +08:00

110 lines
3.4 KiB
HLSL

// Copyright Epic Games, Inc. All Rights Reserved.
/*=============================================================================
PostProcessBloom.usf: PostProcessing bloom
=============================================================================*/
#define EYE_ADAPTATION_LOOSE_PARAMETERS 1
#include "Common.ush"
#include "PostProcessCommon.ush"
#include "EyeAdaptationCommon.ush"
#include "PostProcessHistogramCommon.ush"
#include "ScreenPass.ush"
SCREEN_PASS_TEXTURE_VIEWPORT(Input)
Texture2D InputTexture;
SamplerState InputSampler;
Texture3D LumBilateralGrid;
SamplerState LumBilateralGridSampler;
Texture2D BlurredLogLum;
SamplerState BlurredLogLumSampler;
float BloomThreshold;
float2 GetExposureScaleMiddleGreyLumValue()
{
float2 ExposureScaleMiddleGreyLumValue = EyeAdaptationLookupBuffer(EyeAdaptationBuffer).xw;
// Middle grey lum value adjusted by exposure compensation
ExposureScaleMiddleGreyLumValue.y = log2(0.18f * ExposureScaleMiddleGreyLumValue.y * LocalExposure_MiddleGreyExposureCompensation);
return ExposureScaleMiddleGreyLumValue;
}
float4 BloomSetupCommon(float2 UV, float2 ViewportUV, float2 ExposureScaleMiddleGreyLumValue)
{
float4 SceneColor = Texture2DSample(InputTexture, InputSampler, UV) * View.OneOverPreExposure;
float ExposureScale = ExposureScaleMiddleGreyLumValue.x;
#if USE_LOCAL_EXPOSURE
{
float LuminanceVal = CalculateEyeAdaptationLuminance(SceneColor.rgb);
float LogLuminance = log2(LuminanceVal);
float MiddleGreyLumValue = ExposureScaleMiddleGreyLumValue.y;
float BaseLogLum = CalculateBaseLogLuminance(LogLuminance, LocalExposure_BlurredLuminanceBlend, ExposureScale, ViewportUV, LumBilateralGrid, BlurredLogLum, LumBilateralGridSampler, BlurredLogLumSampler);
float LocalExposure = CalculateLocalExposure(LogLuminance + log2(ExposureScale), BaseLogLum, MiddleGreyLumValue, LocalExposure_HighlightContrastScale, LocalExposure_ShadowContrastScale, LocalExposure_DetailStrength);
SceneColor.rgb *= LocalExposure;
}
#endif
half3 LinearColor = SceneColor.rgb;
#if USE_THRESHOLD
half TotalLuminance = Luminance(LinearColor) * ExposureScale;
half BloomLuminance = TotalLuminance - BloomThreshold;
half BloomAmount = saturate(BloomLuminance * 0.5f);
#else
half BloomAmount = 1.0f;
#endif
return float4(BloomAmount * LinearColor, 0) * View.PreExposure;
}
#if PIXELSHADER
FScreenTransform SvPositionToInputTextureUV;
void BloomSetupPS(
float4 SvPosition : SV_POSITION,
out float4 OutColor : SV_Target0)
{
float2 UV = ApplyScreenTransform(SvPosition.xy, SvPositionToInputTextureUV);
float2 ViewportUV = (int2(SvPosition.xy) - Input_ViewportMin) * Input_ViewportSizeInverse;
float2 ExposureScaleMiddleGreyLumValue = GetExposureScaleMiddleGreyLumValue();
OutColor = BloomSetupCommon(UV, ViewportUV, ExposureScaleMiddleGreyLumValue);
}
#elif COMPUTESHADER
RWTexture2D<float4> RWOutputTexture;
[numthreads(THREADGROUP_SIZEX, THREADGROUP_SIZEY, 1)]
void BloomSetupCS(uint2 DispatchThreadId : SV_DispatchThreadID)
{
float2 UV = ((float2)DispatchThreadId + (float2)Input_ViewportMin + 0.5f) * Input_ExtentInverse;
if (IsComputeUVOutOfBounds(UV))
{
return;
}
float2 ViewportUV = DispatchThreadId * Input_ViewportSizeInverse;
float2 ExposureScaleMiddleGreyLumValue = GetExposureScaleMiddleGreyLumValue();
float4 OutColor = BloomSetupCommon(UV, ViewportUV, ExposureScaleMiddleGreyLumValue);
uint2 PixelPos = DispatchThreadId + Input_ViewportMin;
RWOutputTexture[PixelPos] = OutColor;
}
#endif