FirstPersonSceneExtension.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "SceneExtensions.h"
 
class FPrimitiveSceneInfo;
class FViewInfo;
 
// Holds collective bounds of all FirstPerson/WorldSpaceRepresentation primitives for a given view. This assumes that these primitives are all very close together in world space,
// allowing to do a single overlap/intersection test to cover all the primitives.
struct FFirstPersonViewBounds
{
    // Collective bounds for all FirstPerson primitives visible in this view.
    FBoxSphereBounds FirstPersonBounds = FBoxSphereBounds(ForceInit);
 
    // Collective bounds for all FirstPersonWorldSpaceRepresentation primitives affecting this view.
    FBoxSphereBounds WorldSpaceRepresentationBounds = FBoxSphereBounds(ForceInit);
    
    // Whether the scene has at least one FirstPerson primitive visible in this view.
    uint32 bHasFirstPersonPrimitives : 1 = false;
 
    // Whether the scene has at least one FirstPersonWorldSpaceRepresentation primitive affecting this view.
    uint32 bHasFirstPersonWorldSpaceRepresentationPrimitives : 1 = false;
};
 
// This scene extension maintains dense arrays of all FirstPerson and FirstPersonWorldSpaceRepresentation primitives in the scene.
// Every frame, it then computes collective per-view for all the first person relevant primitives affecting each view.
// Currently, these bounds are used for First Person Self-Shadow and Lumen HWRT reflections.
class FFirstPersonSceneExtension : public ISceneExtension
{
    DECLARE_SCENE_EXTENSION(RENDERER_API, FFirstPersonSceneExtension);
public:
    using ISceneExtension::ISceneExtension;
 
    static bool ShouldCreateExtension(FScene& Scene);
 
    //~ Begin ISceneExtension Interface.
    virtual ISceneExtensionUpdater* CreateUpdater() override;
    virtual ISceneExtensionRenderer* CreateRenderer(FSceneRendererBase& InSceneRenderer, const FEngineShowFlags& EngineShowFlags) override;
    //~ End ISceneExtension Interface.
 
    const TArray<FPrimitiveSceneInfo*>& GetFirstPersonPrimitives() const;
    const TArray<FPrimitiveSceneInfo*>& GetWorldSpaceRepresentationPrimitives() const;
 
private:
 
    // Private updater class for handling adding and removal of primitives.
    class FUpdater : public ISceneExtensionUpdater
    {
        DECLARE_SCENE_EXTENSION_UPDATER(FUpdater, FFirstPersonSceneExtension);
    public:
        FUpdater(FFirstPersonSceneExtension& InSceneExtension) : SceneExtension(InSceneExtension) {}
 
        //~ Begin ISceneExtensionUpdater Interface.
        virtual void PreSceneUpdate(FRDGBuilder& GraphBuilder, const FScenePreUpdateChangeSet& ChangeSet, FSceneUniformBuffer& SceneUniforms) override;
        virtual void PostSceneUpdate(FRDGBuilder& GraphBuilder, const FScenePostUpdateChangeSet& ChangeSet) override;
        //~ End ISceneExtensionUpdater Interface.
 
    private:
        FFirstPersonSceneExtension& SceneExtension;
    };
 
    TArray<FPrimitiveSceneInfo*> FirstPersonPrimitives;
    TArray<FPrimitiveSceneInfo*> WorldSpaceRepresentationPrimitives;
};
 
// First person "renderer" class, calculating the per-view bounds when a frame is rendered.
class FFirstPersonSceneExtensionRenderer : public ISceneExtensionRenderer
{
    DECLARE_SCENE_EXTENSION_RENDERER(FRenderer, FFirstPersonSceneExtension);
public:
    FFirstPersonSceneExtensionRenderer(FSceneRendererBase& InSceneRenderer, FFirstPersonSceneExtension& InSceneExtension)
        : ISceneExtensionRenderer(InSceneRenderer), SceneExtension(InSceneExtension) {
    }
 
    //~ Begin ISceneExtensionRenderer Interface.
    virtual void UpdateViewData(FRDGBuilder& GraphBuilder, const FRendererViewDataManager& ViewDataManager) override;
    //~ End ISceneExtensionRenderer Interface.
 
    FFirstPersonViewBounds GetFirstPersonViewBounds(const FViewInfo& ViewInfo) const;
 
private:
    FFirstPersonSceneExtension& SceneExtension;
    TArray<FFirstPersonViewBounds> ViewBoundsArray;
};