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UnrealEngine/Engine/Source/Editor/UnrealEd/Classes/ThumbnailRendering/ThumbnailRenderer.h
2025-05-18 13:04:45 +08:00

117 lines
5.0 KiB
C++

// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
#include "CoreMinimal.h"
#include "UObject/ObjectMacros.h"
#include "UObject/Object.h"
#include "ThumbnailRenderer.generated.h"
class FCanvas;
class FRenderTarget;
/** Refresh frequency for thumbnail rendering, listed from most to least CPU demanding / frequent */
enum class EThumbnailRenderFrequency : uint8
{
/** Always render when requested, used for assets needing live animated thumbnails like materials */
Realtime,
/** Render whenever a property has changed on request */
OnPropertyChange,
/** Render only on asset save */
OnAssetSave,
/** Render thumbnail only once */
Once,
};
/**
* This is an abstract base class that is used to define the interface that
* UnrealEd will use when rendering a given object's thumbnail. The editor
* only calls the virtual rendering function.
*/
UCLASS(abstract, MinimalAPI)
class UThumbnailRenderer : public UObject
{
GENERATED_UCLASS_BODY()
public:
/**
* Returns true if the renderer is capable of producing a thumbnail for the specified asset.
*
* @param Object the asset to attempt to render
*/
virtual bool CanVisualizeAsset(UObject* Object) { return true; }
/**
* Calculates the size the thumbnail would be at the specified zoom level
*
* @param Object the object the thumbnail is of
* @param Zoom the current multiplier of size
* @param OutWidth the var that gets the width of the thumbnail
* @param OutHeight the var that gets the height
*/
virtual void GetThumbnailSize(UObject* Object, float Zoom, uint32& OutWidth, uint32& OutHeight) const PURE_VIRTUAL(UThumbnailRenderer::GetThumbnailSize,);
/**
* Draws a thumbnail for the object that was specified.
*
* @param Object the object to draw the thumbnail for
* @param X the X coordinate to start drawing at
* @param Y the Y coordinate to start drawing at
* @param Width the width of the thumbnail to draw
* @param Height the height of the thumbnail to draw
* @param Viewport the viewport being drawn in
* @param Canvas the render interface to draw with
*/
UE_DEPRECATED(4.25, "Please override the other prototype of the Draw function.")
virtual void Draw(UObject* Object, int32 X, int32 Y, uint32 Width, uint32 Height, FRenderTarget* Viewport, FCanvas* Canvas) { Draw(Object, X, Y, Width, Height, Viewport, Canvas, false); }
/**
* Draws a thumbnail for the object that was specified.
*
* @param Object the object to draw the thumbnail for
* @param X the X coordinate to start drawing at
* @param Y the Y coordinate to start drawing at
* @param Width the width of the thumbnail to draw
* @param Height the height of the thumbnail to draw
* @param Viewport the viewport being drawn in
* @param Canvas the render interface to draw with
* @param bAdditionalViewFamily whether this draw should write over the render target (true) or clear it before (false)
*/
virtual void Draw(UObject* Object, int32 X, int32 Y, uint32 Width, uint32 Height, FRenderTarget* Viewport, FCanvas* Canvas, bool bAdditionalViewFamily) PURE_VIRTUAL(UThumbnailRenderer::Draw, );
/**
* Checks to see if the specified asset supports realtime thumbnails, which will cause them to always be rerendered to reflect any changes
* made to the asset. If this is false, thumbnails should render once and then not update again.
* For most renderers, this should remain as true.
*
* @param Object The asset to draw the thumbnail for
*
* @return True if the thumbnail needs to always be redrawn, false if it can be just drawn once and then reused.
*/
UE_DEPRECATED(5.2, "Please override GetThumbnailRenderFrequency instead, AllowsRealtimeThumbnails is not used.")
virtual bool AllowsRealtimeThumbnails(UObject* Object) const { return true; }
/**
* Override this method to control the render frequency for thumbnails in your editor
* Generally speaking you should use Realtime if you want an animated thumbnail, but if not it is expensive to use (per-frame draws)
* If not using realtime, the next best default is OnAssetSave, which updates the thumbnail only save.
* Remaining types are not suggested unless you have specific asset thumbnail update needs.
*
* @TODO: The current default of Realtime maintains legacy behavior, but is overally agressive / for frequent than needed for most.
*
* @return ThumbnailRenderer-specific frequency for thumbnail updates
*/
virtual EThumbnailRenderFrequency GetThumbnailRenderFrequency(UObject* Object) const { return EThumbnailRenderFrequency::Realtime; }
protected:
/** Renders the thumbnail's view family. */
UNREALED_API static void RenderViewFamily(FCanvas* Canvas, class FSceneViewFamily* ViewFamily, class FSceneView* View);
UE_DEPRECATED(5.0, "Please use the prototype of RenderViewFamily which takes a non-const view in parameter : like the view family the view is still not quite final until SetupView is called.")
UNREALED_API static void RenderViewFamily(FCanvas* Canvas, class FSceneViewFamily* ViewFamily);
UNREALED_API static struct FGameTime GetTime();
};