DebugCanvas.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "RenderResource.h"
#include "RendererInterface.h"
#include "Rendering/RenderingCommon.h"
#include "CanvasTypes.h"
#include "Widgets/SLeafWidget.h"
#include "Engine/TextureRenderTarget2D.h"
 
class FRHICommandListImmediate;
class FSceneViewport;
class FViewportClient;
 
typedef TSharedPtr<FCanvas, ESPMode::ThreadSafe> FCanvasPtr;
 
class SDebugCanvas : public SLeafWidget
{
    SLATE_BEGIN_ARGS(SDebugCanvas)
    {
        _Visibility = EVisibility::HitTestInvisible;
    }
 
    SLATE_ATTRIBUTE(FSceneViewport*, SceneViewport)
 
    SLATE_END_ARGS()
 
public:
    ENGINE_API SDebugCanvas();
 
    ENGINE_API void Construct(const FArguments& InArgs);
 
    ENGINE_API int32 OnPaint(const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyCullingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled) const override;
    ENGINE_API virtual FVector2D ComputeDesiredSize(float LayoutScaleMultiplier) const override;
 
    ENGINE_API void SetSceneViewport(FSceneViewport* InSceneViewport);
private:
    TAttribute<FSceneViewport*> SceneViewport;
};
 
class FDebugCanvasDrawer : public ICustomSlateElement, public FGCObject
{
public:
    FDebugCanvasDrawer();
    ~FDebugCanvasDrawer();
 
    FCanvas* GetGameThreadDebugCanvas();
 
    void BeginRenderingCanvas( const FIntRect& InCanvasRect );
 
    void InitDebugCanvas(FViewportClient* ViewportClient, UWorld* InWorld);
 
    UE_DEPRECATED(5.6, "There are no longer any render thread resources to release. Call ReleaseInternalTexture() on the game thread instead.")
    void ReleaseResources() {}
 
    void ReleaseInternalTexture();
 
    // FGCObject interface
    virtual void AddReferencedObjects(FReferenceCollector& Collector) override;
    virtual FString GetReferencerName() const override { return TEXT("FDebugCanvasDrawer"); }
 
private:
    virtual void Draw_RenderThread(FRDGBuilder& GraphBuilder, const FDrawPassInputs& Inputs) override;
 
    void DeleteRenderThreadCanvas();
 
    FCanvasPtr GetRenderThreadCanvas();
 
    void SetRenderThreadCanvas(const FIntRect& InCanvasRect, FCanvasPtr& Canvas, class FTextureRenderTargetResource* LayerResource);
 
    void HandleReleaseFontResources(const class FSlateFontCache& InFontCache);
 
private:
    FCanvasPtr GameThreadCanvas;
    FCanvasPtr RenderThreadCanvas;
    class FSlateCanvasRenderTarget* RenderTarget;
    TObjectPtr<UTextureRenderTarget2D> LayerTexture;
    class FTextureRenderTargetResource* LayerResource = nullptr;
    uint32 LayerID;
    bool bCanvasRenderedLastFrame;
};