SceneViewExtension.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
/*=============================================================================
    SceneViewExtension.h: Allow changing the view parameters on the render thread
=============================================================================*/
 
#pragma once
 
#include "CoreMinimal.h"
#include "Delegates/DelegateCombinations.h"
#include "RendererInterface.h"
#include "SceneViewExtensionContext.h"
 
#include "SceneTexturesConfig.h"
 
class APlayerController;
class FRHICommandListImmediate;
class FSceneView;
class FSceneViewFamily;
struct FMinimalViewInfo;
struct FSceneViewProjectionData;
class FRDGBuilder;
struct FPostProcessingInputs;
struct FMobilePostProcessingInputs;
struct FPostProcessMaterialInputs;
struct FScreenPassTexture;
class FViewport;
 
 
FUNC_DECLARE_DELEGATE(FPostProcessingPassDelegate, FScreenPassTexture /*ReturnSceneColor*/, FRDGBuilder& /*GraphBuilder*/, const FSceneView& /*View*/, const FPostProcessMaterialInputs& /*Inputs*/)
using FPostProcessingPassDelegateArray = TArray<FPostProcessingPassDelegate, SceneRenderingAllocator>;
 
// Soft deprecation of the previous after pass delegate names
using FAfterPassCallbackDelegate = FPostProcessingPassDelegate;
using FAfterPassCallbackDelegateArray = FPostProcessingPassDelegateArray;
 
enum class ESceneViewExtensionFlags : uint32
{
    None = 0,
 
    SubscribesToPostTLASBuild = 1 << 0
};
ENUM_CLASS_FLAGS(ESceneViewExtensionFlags);
 
class ISceneViewExtension
{
public:
 
    // Each post-processing pass immediately precedes a PPM blend location, if it exists. See comments below.
    enum class EPostProcessingPass : uint32
    {
        BeforeDOF,              // BL_SceneColorBeforeDOF
        AfterDOF,               // BL_SceneColorAfterDOF
        TranslucencyAfterDOF,   // BL_TranslucencyAfterDOF
        SSRInput,               // BL_SSRInput
 
        // The following post-processing passes may be last, and therefore receive a valid OverrideOutput render target.
        ReplacingTonemapper,    // BL_ReplacingTonemapper
        MotionBlur,             // BL_SceneColorBeforeBloom
        Tonemap,                // BL_SceneColorAfterTonemapping
        FXAA,
        SMAA,
        VisualizeDepthOfField,
 
        MAX
    };
 
public:
 
    virtual void SetupViewFamily(FSceneViewFamily& InViewFamily) {};
 
    virtual void SetupView(FSceneViewFamily& InViewFamily, FSceneView& InView) {}
 
    virtual void SetupViewPoint(APlayerController* Player, FMinimalViewInfo& InViewInfo) {}
 
    virtual void SetupViewProjectionMatrix(FSceneViewProjectionData& InOutProjectionData) {}
 
    virtual void BeginRenderViewFamily(FSceneViewFamily& InViewFamily) {};
 
    virtual void PostCreateSceneRenderer(const FSceneViewFamily& InViewFamily, ISceneRenderer* Renderer) {}
 
    virtual void PreRenderViewFamily_RenderThread(FRDGBuilder& GraphBuilder, FSceneViewFamily& InViewFamily) {}
 
    virtual void PreRenderView_RenderThread(FRDGBuilder& GraphBuilder, FSceneView& InView) {}
 
    virtual void PreInitViews_RenderThread(FRDGBuilder& GraphBuilder) {}
 
    virtual void PreRenderBasePass_RenderThread(FRDGBuilder& GraphBuilder, bool bDepthBufferIsPopulated) {}
 
    virtual void PostRenderBasePassDeferred_RenderThread(FRDGBuilder& GraphBuilder, FSceneView& InView, const FRenderTargetBindingSlots& RenderTargets, TRDGUniformBufferRef<FSceneTextureUniformParameters> SceneTextures) {}
 
    virtual void PostRenderBasePassMobile_RenderThread(FRHICommandList& RHICmdList, FSceneView& InView) {}
 
    virtual void PostTLASBuild_RenderThread(FRDGBuilder& GraphBuilder, FSceneView& InView) {}
 
    virtual void PrePostProcessPass_RenderThread(FRDGBuilder& GraphBuilder, const FSceneView& InView, const FPostProcessingInputs& Inputs) {};
 
    virtual void PrePostProcessPassMobile_RenderThread(FRDGBuilder& GraphBuilder, const FSceneView& InView, const FMobilePostProcessingInputs& Inputs) {};
 
    virtual void SubscribeToPostProcessingPass(EPostProcessingPass Pass, const FSceneView& InView, FPostProcessingPassDelegateArray& InOutPassCallbacks, bool bIsPassEnabled) {}
 
    virtual void PostRenderViewFamily_RenderThread(FRDGBuilder& GraphBuilder, FSceneViewFamily& InViewFamily) {}
 
    virtual void PostRenderView_RenderThread(FRDGBuilder& GraphBuilder, FSceneView& InView) {}
 
    virtual int32 GetPriority() const { return 0; }
 
    virtual bool IsActiveThisFrame(const FSceneViewExtensionContext& Context) const { return IsActiveThisFrame_Internal(Context); }
 
    virtual ESceneViewExtensionFlags GetFlags() const { return ESceneViewExtensionFlags::None; }
 
 
    UE_DEPRECATED(5.5, "SubscribeToPostProcessingPass now takes a SceneView")
    virtual void SubscribeToPostProcessingPass(EPostProcessingPass Pass, FPostProcessingPassDelegateArray& InOutPassCallbacks, bool bIsPassEnabled) {}
 
 
protected:
    virtual bool IsActiveThisFrame_Internal(const FSceneViewExtensionContext& Context) const { return true; }
};
 
 
 
class FAutoRegister
{
    friend class FSceneViewExtensions;
    FAutoRegister(){}
};
 
 
class FSceneViewExtensionBase : public ISceneViewExtension, public TSharedFromThis<FSceneViewExtensionBase, ESPMode::ThreadSafe>
{
public:
    ENGINE_API FSceneViewExtensionBase(const FAutoRegister&);
    ENGINE_API virtual ~FSceneViewExtensionBase();
 
    // Array of Functors that can be used to activate an extension for the current frame and given context.
    TArray<FSceneViewExtensionIsActiveFunctor> IsActiveThisFrameFunctions;
 
    // Determines if the extension should be active for the current frame and given context.
    ENGINE_API virtual bool IsActiveThisFrame(const FSceneViewExtensionContext& Context) const override final;
};
 
class FWorldSceneViewExtension : public FSceneViewExtensionBase
{
public:
    ENGINE_API FWorldSceneViewExtension(const FAutoRegister& AutoReg, UWorld* InWorld);
protected:
    ENGINE_API virtual bool IsActiveThisFrame_Internal(const FSceneViewExtensionContext& Context) const override;
    UWorld* GetWorld() const { return World.Get(); }
private:
    TWeakObjectPtr<UWorld> World;
};
 
class FHMDSceneViewExtension : public FSceneViewExtensionBase
{
public:
    FHMDSceneViewExtension(const FAutoRegister& AutoReg) : FSceneViewExtensionBase(AutoReg)
    {
    }
protected:
    ENGINE_API virtual bool IsActiveThisFrame_Internal(const FSceneViewExtensionContext& Context) const override;
};
 
using FSceneViewExtensionRef = TSharedRef<ISceneViewExtension, ESPMode::ThreadSafe>;
 
class FSceneViewExtensions
{
    friend class FSceneViewExtensionBase;
 
public:
    template<typename ExtensionType, typename... TArgs>
    static TSharedRef<ExtensionType, ESPMode::ThreadSafe> NewExtension( TArgs&&... Args )
    {
        TSharedRef<ExtensionType, ESPMode::ThreadSafe> NewExtension = MakeShareable(new ExtensionType( FAutoRegister(), Forward<TArgs>(Args)... ));
        RegisterExtension(NewExtension);
        return NewExtension;
    }
 
    static ENGINE_API void ForEachActiveViewExtension(
        const TArray<TWeakPtr<ISceneViewExtension, ESPMode::ThreadSafe>>& InExtensions, 
        const FSceneViewExtensionContext& InContext,
        const TFunctionRef<void(const FSceneViewExtensionRef&)>& Func);
 
    ENGINE_API const TArray<FSceneViewExtensionRef> GatherActiveExtensions(const FSceneViewExtensionContext& InContext) const;
 
private:
    static ENGINE_API void RegisterExtension(const FSceneViewExtensionRef& RegisterMe);
    TArray< TWeakPtr<ISceneViewExtension, ESPMode::ThreadSafe> > KnownExtensions;
};