打扮家viewport视频

 

 if和else

 

viewport相关类型

 gameviewportClient

 

 

 

 

template<ESlateVertexRounding Rounding>
void FSlateElementBatcher::AddViewportElement( const FSlateDrawElement& DrawElement )
{
	const FSlateRenderTransform& RenderTransform = DrawElement.GetRenderTransform();
	const FVector2D& LocalSize = DrawElement.GetLocalSize();
	const FSlateViewportPayload& DrawElementPayload = DrawElement.GetDataPayload<FSlateViewportPayload>();
	ESlateDrawEffect InDrawEffects = DrawElement.GetDrawEffects();
	const int32 Layer = DrawElement.GetLayer();

	const FColor FinalColor = PackVertexColor(DrawElementPayload.GetTint());

	ESlateBatchDrawFlag DrawFlags = DrawElement.GetBatchFlags();

	FSlateShaderResource* ViewportResource = DrawElementPayload.RenderTargetResource;
	ESlateShader ShaderType = ESlateShader::Default;

	if(DrawElementPayload.bViewportTextureAlphaOnly )
	{
		// This is a slight hack, but the grayscale font shader is the same as the general shader except it reads alpha only textures and doesn't support tiling
		ShaderType = ESlateShader::GrayscaleFont;
	}

	FSlateRenderBatch& RenderBatch = CreateRenderBatch( Layer, FShaderParams(), ViewportResource, ESlateDrawPrimitive::TriangleList, ShaderType, InDrawEffects, DrawFlags, DrawElement);

	// Tag this batch as requiring vsync if the viewport requires it.
	if( ViewportResource != nullptr && !DrawElementPayload.bAllowViewportScaling )
	{
		bRequiresVsync |= DrawElementPayload.bRequiresVSync;
	}

	// Do pixel snapping
	FVector2D TopLeft(0,0);
	FVector2D BotRight(LocalSize);

	// If the viewport disallows scaling, force size to current texture size.
	if (ViewportResource != nullptr && !DrawElementPayload.bAllowViewportScaling)
	{
		const float ElementScale = DrawElement.GetScale();
		BotRight = FVector2D(ViewportResource->GetWidth() / ElementScale, ViewportResource->GetHeight() / ElementScale);
	}

	FVector2D TopRight = FVector2D( BotRight.X, TopLeft.Y);
	FVector2D BotLeft =	 FVector2D( TopLeft.X, BotRight.Y);

	// The start index of these vertices in the index buffer
	const uint32 IndexStart = 0;

	// Add four vertices to the list of verts to be added to the vertex buffer
	RenderBatch.AddVertex( FSlateVertex::Make<Rounding>( RenderTransform, TopLeft,	FVector2D(0.0f,0.0f),	FinalColor ) );
	RenderBatch.AddVertex( FSlateVertex::Make<Rounding>( RenderTransform, TopRight,	FVector2D(1.0f,0.0f),	FinalColor ) );
	RenderBatch.AddVertex( FSlateVertex::Make<Rounding>( RenderTransform, BotLeft,	FVector2D(0.0f,1.0f),	FinalColor ) );
	RenderBatch.AddVertex( FSlateVertex::Make<Rounding>( RenderTransform, BotRight,	FVector2D(1.0f,1.0f),	FinalColor ) );

	// Add 6 indices to the vertex buffer.  (2 tri's per quad, 3 indices per tri)
	RenderBatch.AddIndex( IndexStart + 0 );
	RenderBatch.AddIndex( IndexStart + 1 );
	RenderBatch.AddIndex( IndexStart + 2 );

	RenderBatch.AddIndex( IndexStart + 2 );
	RenderBatch.AddIndex( IndexStart + 1 );
	RenderBatch.AddIndex( IndexStart + 3 );
}