Fixes and updates to graphics api

Source/Engine/Graphics/GPUSwapChain.cpp

@@ -1,6 +1,7 @@
 // Copyright (c) Wojciech Figat. All rights reserved.
 
 #include "GPUSwapChain.h"
+#include "GPUContext.h"
 #include "GPUDevice.h"
 #include "Textures/GPUTexture.h"
 #include "Engine/Core/Log.h"
@@ -42,6 +43,11 @@ GPUSwapChain::GPUSwapChain()
 #endif
 }
 
+void GPUSwapChain::CopyBackbuffer(GPUContext* context, GPUTexture* dst)
+{
+    context->Draw(dst, GetBackBufferView());
+}
+
 Task* GPUSwapChain::DownloadDataAsync(TextureData& result)
 {
     if (_downloadTask)