void FRCPassPostProcessWeightedSampleSum::Process(FRenderingCompositePassContext& Context)
{
	const FSceneView& View = Context.View;

	FRenderingCompositeOutput *Input = GetInput(ePId_Input0)->GetOutput();

	// input is not hooked up correctly
	check(Input);

	const FPooledRenderTargetDesc* InputDesc = GetInputDesc(ePId_Input0);

	// input is not hooked up correctly
	check(InputDesc);

	const FSceneViewFamily& ViewFamily = *(View.Family);

	FIntPoint SrcSize = InputDesc->Extent;
	FIntPoint DestSize = PassOutputs[0].RenderTargetDesc.Extent;
	FSceneRenderTargets& SceneContext = FSceneRenderTargets::Get(Context.RHICmdList);

	// e.g. 4 means the input texture is 4x smaller than the buffer size
	FIntPoint SrcScaleFactor = SceneContext.GetBufferSizeXY() / SrcSize;
	FIntPoint DstScaleFactor = SceneContext.GetBufferSizeXY() / DestSize;

	TRefCountPtr<IPooledRenderTarget> InputPooledElement = Input->RequestInput();

	check(!InputPooledElement->IsFree());

	const FSceneRenderTargetItem& DestRenderTarget = PassOutputs[0].RequestSurface(Context);

	bool bDoFastBlur = DoFastBlur();

	FVector2D InvSrcSize(1.0f / SrcSize.X, 1.0f / SrcSize.Y);
	// we scale by width because FOV is defined horizontally
	float SrcSizeForThisAxis = View.ViewRect.Width() / (float)SrcScaleFactor.X;

	if(bDoFastBlur && FilterShape == EFS_Vert)
	{
		SrcSizeForThisAxis *= 2.0f;
	}

	// in texel (input resolution), /2 as we use the diameter, 100 as we use percent
	float EffectiveBlurRadius = SizeScale * SrcSizeForThisAxis  / 2 / 100.0f;

	FVector2D BlurOffsets[MAX_FILTER_SAMPLES];
	FLinearColor BlurWeights[MAX_FILTER_SAMPLES];
	FVector2D OffsetAndWeight[MAX_FILTER_SAMPLES];

	const auto FeatureLevel = Context.View.GetFeatureLevel();

	// compute 1D filtered samples
	uint32 MaxNumSamples = GetMaxNumSamples(FeatureLevel);

	uint32 NumSamples = Compute1DGaussianFilterKernel(FeatureLevel, EffectiveBlurRadius, OffsetAndWeight, MaxNumSamples, FilterShape, CrossCenterWeight);

	FIntRect DestRect = FIntRect::DivideAndRoundUp(View.ViewRect, DstScaleFactor);

	SCOPED_DRAW_EVENTF(Context.RHICmdList, PostProcessWeightedSampleSum, TEXT("PostProcessWeightedSampleSum#%d %dx%d in %dx%d"),
		NumSamples, DestRect.Width(), DestRect.Height(), DestSize.X, DestSize.Y);

	// compute weights as weighted contributions of the TintValue
	for(uint32 i = 0; i < NumSamples; ++i)
	{
		BlurWeights[i] = TintValue * OffsetAndWeight[i].Y;
	}

	SetRenderTarget(Context.RHICmdList, DestRenderTarget.TargetableTexture, FTextureRHIRef(), ESimpleRenderTargetMode::EExistingColorAndDepth);

	Context.SetViewportAndCallRHI(0, 0, 0.0f, DestSize.X, DestSize.Y, 1.0f);

	bool bRequiresClear = true;
	// check if we have to clear the whole surface.
	// Otherwise perform the clear when the dest rectangle has been computed.
	if (FeatureLevel == ERHIFeatureLevel::ES2 || FeatureLevel == ERHIFeatureLevel::ES3_1)
	{
		Context.RHICmdList.Clear(true, FLinearColor(0, 0, 0, 0), false, 1.0f, false, 0, FIntRect());
		bRequiresClear = false;
	}

	FIntRect SrcRect = FIntRect::DivideAndRoundUp(View.ViewRect, SrcScaleFactor);
	if (bRequiresClear)
	{
		DrawClear(Context.RHICmdList, FeatureLevel, bDoFastBlur, SrcRect, DestRect, DestSize);
	}

	// set the state
	Context.RHICmdList.SetBlendState(TStaticBlendState<>::GetRHI());
	Context.RHICmdList.SetRasterizerState(TStaticRasterizerState<>::GetRHI());
	Context.RHICmdList.SetDepthStencilState(TStaticDepthStencilState<false, CF_Always>::GetRHI());

	const FTextureRHIRef& FilterTexture = InputPooledElement->GetRenderTargetItem().ShaderResourceTexture;

	FRenderingCompositeOutputRef* NodeInput1 = GetInput(ePId_Input1);

	FRenderingCompositeOutput *Input1 = NodeInput1 ? NodeInput1->GetOutput() : 0;

	uint32 CombineMethodInt = 0;

	if(CombineMethod == EFCM_MaxMagnitude)
	{
		CombineMethodInt = 2;
	}

	// can be optimized
	FTextureRHIRef AdditiveTexture;

	if(Input1)
	{
		TRefCountPtr<IPooledRenderTarget> InputPooledElement1 = Input1->RequestInput();
		AdditiveTexture = InputPooledElement1->GetRenderTargetItem().ShaderResourceTexture;

		check(CombineMethod == EFCM_Weighted);

		CombineMethodInt = 1;
	}

	if (FilterShape == EFS_Horiz)
	{
		float YOffset = bDoFastBlur ? (InvSrcSize.Y * 0.5f) : 0.0f;
		for (uint32 i = 0; i < NumSamples; ++i)
		{
			BlurOffsets[i] = FVector2D(InvSrcSize.X * OffsetAndWeight[i].X, YOffset);
		}
	}
	else
	{
		float YOffset = bDoFastBlur ? -(InvSrcSize.Y * 0.5f) : 0.0f;
		for (uint32 i = 0; i < NumSamples; ++i)
		{
			BlurOffsets[i] = FVector2D(0, InvSrcSize.Y * OffsetAndWeight[i].X + YOffset);
		}
	}

	FShader* VertexShader = nullptr;
	SetFilterShaders(
		Context.RHICmdList,
		FeatureLevel,
		TStaticSamplerState<SF_Bilinear,AM_Border,AM_Border,AM_Clamp>::GetRHI(),
		FilterTexture,
		AdditiveTexture,
		CombineMethodInt,
		BlurOffsets,
		BlurWeights,
		NumSamples,
		&VertexShader
		);	

	DrawQuad(Context.RHICmdList, FeatureLevel, bDoFastBlur, SrcRect, DestRect, DestSize, SrcSize, VertexShader);

	Context.RHICmdList.CopyToResolveTarget(DestRenderTarget.TargetableTexture, DestRenderTarget.ShaderResourceTexture, false, FResolveParams());
}
void FRCPassPostProcessSubsurfaceExtractSpecular::Process(FRenderingCompositePassContext& Context)
{
	const FPooledRenderTargetDesc* InputDesc = GetInputDesc(ePId_Input0);

	check(InputDesc);

	const FSceneView& View = Context.View;
	const FSceneViewFamily& ViewFamily = *(View.Family);

	FIntPoint SrcSize = InputDesc->Extent;
	FIntPoint DestSize = PassOutputs[0].RenderTargetDesc.Extent;

	check(DestSize.X);
	check(DestSize.Y);
	check(SrcSize.X);
	check(SrcSize.Y);

	//	FIntRect SrcRect = View.ViewRect / ScaleFactor;
	FIntRect SrcRect = View.ViewRect;
	FIntRect DestRect = View.ViewRect;

	TRefCountPtr<IPooledRenderTarget> NewSceneColor;

	const FSceneRenderTargetItem& DestRenderTarget = PassOutputs[0].RequestSurface(Context);

	// Set the view family's render target/viewport.
	SetRenderTarget(Context.RHICmdList, DestRenderTarget.TargetableTexture, FTextureRHIRef());

	Context.SetViewportAndCallRHI(0, 0, 0.0f, DestSize.X, DestSize.Y, 1.0f );

	Context.RHICmdList.SetBlendState(TStaticBlendState<>::GetRHI());
	Context.RHICmdList.SetRasterizerState(TStaticRasterizerState<>::GetRHI());
	Context.RHICmdList.SetDepthStencilState(TStaticDepthStencilState<false, CF_Always>::GetRHI());

	TShaderMapRef<FPostProcessVS> VertexShader(Context.GetShaderMap());

	bool bDoSpecularCorrection = DoSpecularCorrection();

	SCOPED_DRAW_EVENTF(Context.RHICmdList, SubsurfacePass, TEXT("SubsurfacePassExtractSpecular#%d"), (int32)bDoSpecularCorrection);

	uint32 SampleSet = FMath::Clamp(CVarSSSSampleSet.GetValueOnRenderThread(), 0, 2);

	if(bDoSpecularCorrection)
	{
		SetSubsurfaceExtractSpecular<1>(Context, SampleSet);
	}
	else
	{
		SetSubsurfaceExtractSpecular<0>(Context, SampleSet);
	}

	DrawRectangle(
		Context.RHICmdList,
		DestRect.Min.X, DestRect.Min.Y,
		DestRect.Width(), DestRect.Height(),
		SrcRect.Min.X, SrcRect.Min.Y,
		SrcRect.Width(), SrcRect.Height(),
		DestSize,
		SrcSize,
		*VertexShader,
		EDRF_UseTriangleOptimization);

	Context.RHICmdList.CopyToResolveTarget(DestRenderTarget.TargetableTexture, DestRenderTarget.ShaderResourceTexture, false, FResolveParams());
}
void FRCPassPostProcessSubsurface::Process(FRenderingCompositePassContext& Context)
{
	const FPooledRenderTargetDesc* InputDesc = GetInputDesc(ePId_Input0);

	check(InputDesc);

	{
		const IPooledRenderTarget* PooledRT = GetSubsufaceProfileTexture_RT(Context.RHICmdList);

		check(PooledRT);

		// for debugging
		GRenderTargetPool.VisualizeTexture.SetCheckPoint(Context.RHICmdList, PooledRT);
	}

	const FSceneView& View = Context.View;
	const FSceneViewFamily& ViewFamily = *(View.Family);

	FIntPoint SrcSize = InputDesc->Extent;
	FIntPoint DestSize = PassOutputs[0].RenderTargetDesc.Extent;

	check(DestSize.X);
	check(DestSize.Y);
	check(SrcSize.X);
	check(SrcSize.Y);

	FIntRect SrcRect = FIntRect(0, 0, DestSize.X, DestSize.Y);
	FIntRect DestRect = SrcRect;

	TRefCountPtr<IPooledRenderTarget> NewSceneColor;

	const FSceneRenderTargetItem* DestRenderTarget;
	{
		DestRenderTarget = &PassOutputs[0].RequestSurface(Context);

		check(DestRenderTarget);
	}

	// Set the view family's render target/viewport.
	SetRenderTarget(Context.RHICmdList, DestRenderTarget->TargetableTexture, FTextureRHIRef());

	Context.SetViewportAndCallRHI(0, 0, 0.0f, DestSize.X, DestSize.Y, 1.0f );

	Context.RHICmdList.SetBlendState(TStaticBlendState<>::GetRHI());
	Context.RHICmdList.SetRasterizerState(TStaticRasterizerState<>::GetRHI());
	Context.RHICmdList.SetDepthStencilState(TStaticDepthStencilState<false, CF_Always>::GetRHI());

	TShaderMapRef<FPostProcessVS> VertexShader(Context.GetShaderMap());

	SCOPED_DRAW_EVENTF(Context.RHICmdList, SubsurfacePass, TEXT("SubsurfaceDirection#%d"), Direction);

	uint32 SampleSet = FMath::Clamp(CVarSSSSampleSet.GetValueOnRenderThread(), 0, 2);

	if (Direction == 0)
	{
		SetSubsurfaceShaderSampleSet<0>(Context, VertexShader, SampleSet);
	}
	else
	{
		SetSubsurfaceShaderSampleSet<1>(Context, VertexShader, SampleSet);
	}

	DrawPostProcessPass(
		Context.RHICmdList,
		DestRect.Min.X, DestRect.Min.Y,
		DestRect.Width(), DestRect.Height(),
		SrcRect.Min.X, SrcRect.Min.Y,
		SrcRect.Width(), SrcRect.Height(),
		DestSize,
		SrcSize,
		*VertexShader,
		View.StereoPass,
		Context.HasHmdMesh(),
		EDRF_UseTriangleOptimization);

	Context.RHICmdList.CopyToResolveTarget(DestRenderTarget->TargetableTexture, DestRenderTarget->ShaderResourceTexture, false, FResolveParams());
}
void FRCPassPostProcessSubsurfaceRecombine::Process(FRenderingCompositePassContext& Context)
{
	FSceneRenderTargets& SceneContext = FSceneRenderTargets::Get(Context.RHICmdList);
	const FPooledRenderTargetDesc* InputDesc = GetInputDesc(ePId_Input0);

	check(InputDesc);

	const FSceneView& View = Context.View;
	const FSceneViewFamily& ViewFamily = *(View.Family);

	FIntPoint SrcSize = InputDesc->Extent;
	FIntPoint DestSize = SceneContext.GetBufferSizeXY();

	check(DestSize.X);
	check(DestSize.Y);
	check(SrcSize.X);
	check(SrcSize.Y);

	FIntRect SrcRect = FIntRect(0, 0, InputDesc->Extent.X, InputDesc->Extent.Y);
	FIntRect DestRect = View.ViewRect;

	TRefCountPtr<IPooledRenderTarget>& SceneColor = SceneContext.GetSceneColor();

	const FSceneRenderTargetItem& DestRenderTarget = SceneColor->GetRenderTargetItem();

	// Set the view family's render target/viewport.
	SetRenderTarget(Context.RHICmdList, DestRenderTarget.TargetableTexture, FTextureRHIRef());

	Context.SetViewportAndCallRHI(0, 0, 0.0f, DestSize.X, DestSize.Y, 1.0f );

	Context.RHICmdList.SetBlendState(TStaticBlendState<CW_RGBA,BO_Add,BF_SourceAlpha,BF_InverseSourceAlpha,BO_Add,BF_SourceAlpha,BF_InverseSourceAlpha>::GetRHI());
	Context.RHICmdList.SetRasterizerState(TStaticRasterizerState<>::GetRHI());
	Context.RHICmdList.SetDepthStencilState(TStaticDepthStencilState<false, CF_Always>::GetRHI());

	TShaderMapRef<FPostProcessVS> VertexShader(Context.GetShaderMap());

	bool bDoSpecularCorrection = DoSpecularCorrection();

	SCOPED_DRAW_EVENTF(Context.RHICmdList, SubsurfacePass, TEXT("SubsurfacePassRecombine#%d"), (int32)bDoSpecularCorrection);

	if(bDoSpecularCorrection)
	{
		SetSubsurfaceRecombineShader<1>(Context, VertexShader);
	}
	else
	{
		SetSubsurfaceRecombineShader<0>(Context, VertexShader);
	}

	DrawPostProcessPass(
		Context.RHICmdList,
		DestRect.Min.X, DestRect.Min.Y,
		DestRect.Width(), DestRect.Height(),
		SrcRect.Min.X, SrcRect.Min.Y,
		SrcRect.Width(), SrcRect.Height(),
		DestSize,
		SrcSize,
		*VertexShader,
		View.StereoPass,
		Context.HasHmdMesh(),
		EDRF_UseTriangleOptimization);

	Context.RHICmdList.CopyToResolveTarget(DestRenderTarget.TargetableTexture, DestRenderTarget.ShaderResourceTexture, false, FResolveParams());
}