HZB.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "RendererInterface.h"
#include "RenderGraphResources.h"
#include "ScreenPass.h"
 
class FViewInfo;
 
// Include "HZB.ush" on the shader side to declare and use these shader parameters
 
BEGIN_SHADER_PARAMETER_STRUCT(FHZBParameters, )
    // Default HZB (furthest depth)
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, HZBTexture)
    SHADER_PARAMETER_SAMPLER(SamplerState, HZBSampler)
    SHADER_PARAMETER_SAMPLER(SamplerState, HZBTextureSampler)
 
    // Closest depth HZB
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, ClosestHZBTexture)
    SHADER_PARAMETER_SAMPLER(SamplerState, ClosestHZBTextureSampler)
 
    // Furthest depth HZB
    SHADER_PARAMETER_RDG_TEXTURE(Texture2D, FurthestHZBTexture)
    SHADER_PARAMETER_SAMPLER(SamplerState, FurthestHZBTextureSampler)
 
    // Common parameters
    SHADER_PARAMETER(FVector2f, HZBSize)
    SHADER_PARAMETER(FVector2f, HZBViewSize)
    SHADER_PARAMETER(FIntRect,  HZBViewRect)
    SHADER_PARAMETER(FVector2f, ViewportUVToHZBBufferUV)
    SHADER_PARAMETER(FVector4f, HZBUvFactorAndInvFactor)
    SHADER_PARAMETER(FVector4f, HZBUVToScreenUVScaleBias)
    SHADER_PARAMETER(FVector2f, HZBBaseTexelSize)
    SHADER_PARAMETER(FVector2f, SamplePixelToHZBUV)
    SHADER_PARAMETER(uint32,    bIsHZBValid)
    SHADER_PARAMETER(uint32,    bIsFurthestHZBValid)
    SHADER_PARAMETER(uint32,    bIsClosestHZBValid)
    SHADER_PARAMETER(FVector4f, ScreenPosToHZBUVScaleBias)
    SHADER_PARAMETER(FVector2f, DummyHZB)
END_SHADER_PARAMETER_STRUCT()
 
enum class EHZBType : uint8
{
    Dummy = 0,
    ClosestHZB = 1,
    FurthestHZB = 2,
    All = ClosestHZB | FurthestHZB
};
 
FHZBParameters GetHZBParameters(FRDGBuilder& GraphBuilder, const FViewInfo& View, EHZBType InHZBTypes, FRDGTextureRef InClosestHZB, FRDGTextureRef InFurthestHZB);
FHZBParameters GetHZBParameters(FRDGBuilder& GraphBuilder, const FViewInfo& View, EHZBType InHZBTypes);
FHZBParameters GetHZBParameters(FRDGBuilder& GraphBuilder, const FViewInfo& View, bool bUsePreviousHZBAsFallback);
FHZBParameters GetDummyHZBParameters(FRDGBuilder& GraphBuilder);
 
bool IsHZBValid(const FViewInfo& View, EHZBType InHZBTypes, bool bCheckIfProduced=false);
bool IsPreviousHZBValid(const FViewInfo& View, EHZBType InHZBTypes);
 
FRDGTextureRef GetHZBTexture(const FViewInfo& View, EHZBType InHZBTypes);