VariableRateShadingImageManager.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
/*=============================================================================
    ShadingRateAttachment.h: Variable rate shading attachment generation class
    definitions.
=============================================================================*/
 
#pragma once
 
#include "Logging/LogMacros.h"
#include "RHI.h"
#include "RendererInterface.h"
#include "RenderGraphDefinitions.h"
 
struct FMinimalSceneTextures; // Forward declaration from SceneTextures.
 
class IVariableRateShadingImageGenerator;
 
DECLARE_LOG_CATEGORY_EXTERN(LogVRS, Log, All);
 
class FVariableRateShadingImageManager : public FRenderResource
{
public:
    enum EVRSPassType
    {
        BasePass,
        TranslucencyAll,
        NaniteEmitGBufferPass,
        SSAO,
        SSR,
        ReflectionEnvironmentAndSky,
        LightFunctions,
        Decals,
        Num
    };
 
    enum EVRSImageType : uint32
    {
        Disabled = 0,
        Full = 1,
        Conservative = 2
    };
 
    enum class EVRSSourceType : uint32
    {
        FixedFoveation = 0x1,
 
        EyeTrackedFoveation = 0x2,
 
        ContrastAdaptiveShading = 0x4,
 
        // @todo: Add more types here as they're implemented.
 
        All = FixedFoveation | EyeTrackedFoveation | ContrastAdaptiveShading,
 
        XRFoveation = FixedFoveation | EyeTrackedFoveation,
 
        None = 0x0,
    };
 
    FVariableRateShadingImageManager();
    virtual ~FVariableRateShadingImageManager();
 
    virtual void InitRHI(FRHICommandListBase& RHICmdList) override;
    virtual void ReleaseRHI() override;
 
    FRDGTextureRef GetVariableRateShadingImage(FRDGBuilder& GraphBuilder, const FViewInfo& ViewInfo, EVRSPassType PassType, bool bRequestSoftwareImage = false);
 
    void PrepareImageBasedVRS(FRDGBuilder& GraphBuilder, const FSceneViewFamily& ViewFamily, const FMinimalSceneTextures& SceneTextures);
 
    bool IsTypeEnabledForView(const FSceneView& View, EVRSSourceType Type);
 
    RENDERER_API void RegisterExternalImageGenerator(IVariableRateShadingImageGenerator* ExternalGenerator);
    RENDERER_API void UnregisterExternalImageGenerator(IVariableRateShadingImageGenerator* ExternalGenerator);
 
    static bool IsHardwareVRSSupported();
    static bool IsSoftwareVRSSupported();
 
    RENDERER_API bool IsPipelineVRSEnabled() const;
    RENDERER_API bool IsAttachmentVRSEnabled() const;
 
    RENDERER_API bool IsVRSEnabledForFrame()  const;
    RENDERER_API bool IsHardwareVRSEnabledForFrame() const;
    RENDERER_API bool IsSoftwareVRSEnabledForFrame() const;
 
    UE_DEPRECATED(5.5, "IsHardwareVRSEnabled() is deprecated, please use IsHardwareVRSEnabledForFrame() instead.")
    bool IsHardwareVRSEnabled() { return IsHardwareVRSEnabledForFrame(); };
 
    UE_DEPRECATED(5.5, "IsSoftwareVRSEnabled() is deprecated, please use IsSoftwareVRSEnabledForFrame() instead.")
    bool IsSoftwareVRSEnabled() { return IsSoftwareVRSEnabledForFrame(); };
 
    bool GetNeedStaticMeshUpdate() const;
    void SetNeedStaticMeshUpdate(bool bInNeedStaticMeshUpdate);
 
    static bool IsVRSCompatibleWithView(const FViewInfo& View);
    static bool IsVRSCompatibleWithOutputType(const EDisplayOutputFormat& DisplayOutputFormat);
 
    static FIntPoint GetSRITileSize(bool bSoftwareSize = false);
    static FRDGTextureDesc GetSRIDesc(const FSceneViewFamily& ViewFamily, bool bSoftwareSize = false);
    static int32 GetNumberOfSupportedRates();
 
    void DrawDebugPreview(FRDGBuilder& GraphBuilder, const FSceneViewFamily& ViewFamily, FRDGTextureRef OutputSceneColor);
 
private:
    TRefCountPtr<IPooledRenderTarget> MobileHMDFixedFoveationOverrideImage;
    // Used to access the generators functionalities.
    TArray<IVariableRateShadingImageGenerator*> ImageGenerators;
    TArray<IVariableRateShadingImageGenerator*> ActiveGenerators;
    // This is used only to own the memory of generators created in the FVariableRateShadingImageManager constructor.
    TArray<TUniquePtr<IVariableRateShadingImageGenerator>> InternalGenerators;
    // Guards ImageGenerators because most of the calls of the manager are on the render thread but the 
    // Register/UnregisterExternalImageGenerator could come from the game thread.
    FRWLock GeneratorsMutex;
 
    FRDGTextureRef CombineShadingRateImages(FRDGBuilder& GraphBuilder, const FSceneViewFamily& ViewFamily, TArray<FRDGTextureRef> Sources);
    FRDGTextureRef GetForceRateImage(FRDGBuilder& GraphBuilder, const FSceneViewFamily& ViewFamily, int RateIndex = 0, bool bGetSoftwareImage = false);
 
    UE_DEPRECATED(5.5, "This version of GetForceRateImage is deprecated, please use GetForceRateImage(FRDGBuilder& GraphBuilder, const FSceneViewFamily& ViewFamily, int RateIndex, bool bGetSoftwareImage) instead.")
    FRDGTextureRef GetForceRateImage(FRDGBuilder& GraphBuilder, const FSceneViewFamily& ViewFamily, int RateIndex = 0,
        EVRSImageType ImageType = EVRSImageType::Full, bool bGetSoftwareImage = false) { return GetForceRateImage(GraphBuilder, ViewFamily, RateIndex, bGetSoftwareImage); };
 
    EVRSImageType GetImageTypeFromPassType(EVRSPassType PassType);
 
    bool bHardwareVRSEnabledForFrame = false;
    bool bSoftwareVRSEnabledForFrame = false;
    int32 VRSForceRateForFrame = -1;
 
    bool bNeedStaticMeshUpdate = false;
};
 
ENUM_CLASS_FLAGS(FVariableRateShadingImageManager::EVRSSourceType);
 
RENDERER_API extern TGlobalResource<FVariableRateShadingImageManager> GVRSImageManager;
 
class IVariableRateShadingImageGenerator
{
public:
    virtual ~IVariableRateShadingImageGenerator() {};
 
    // Returns cached VRS image.
    virtual FRDGTextureRef GetImage(FRDGBuilder& GraphBuilder, const FViewInfo& ViewInfo, FVariableRateShadingImageManager::EVRSImageType ImageType, bool bGetSoftwareImage = false) = 0;
 
    // Generates image(s) and saves to generator cache. Should only be run once per view per frame, in Render().
    virtual void PrepareImages(FRDGBuilder& GraphBuilder, const FSceneViewFamily& ViewFamily, const FMinimalSceneTextures& SceneTextures, bool bPrepareHardwareImages, bool bPrepareSoftwareImages) = 0;
 
    // Returns whether or not generator is enabled - can change at runtime
    virtual bool IsEnabled() const { return false; };
 
    // Returns whether or not the given view supports this generator
    virtual bool IsSupportedByView(const FSceneView& View) const { return false; };
 
    // Return bitmask of generator type
    virtual FVariableRateShadingImageManager::EVRSSourceType GetType() const { return FVariableRateShadingImageManager::EVRSSourceType::None; };
 
    // Get VRS image to be used w/ debug overlay
    virtual FRDGTextureRef GetDebugImage(FRDGBuilder& GraphBuilder, const FViewInfo& ViewInfo, FVariableRateShadingImageManager::EVRSImageType ImageType, bool bGetSoftwareImage = false) = 0;
};