wined3d: Cleanup IWineD3DDeviceImpl_GetBackBuffer().

dlls/wined3d/device.c

@@ -4009,22 +4009,31 @@ static HRESULT WINAPI IWineD3DDeviceImpl_GetTexture(IWineD3DDevice *iface, DWORD
 /*****
  * Get Back Buffer
  *****/
-static HRESULT WINAPI IWineD3DDeviceImpl_GetBackBuffer(IWineD3DDevice *iface, UINT iSwapChain, UINT BackBuffer, WINED3DBACKBUFFER_TYPE Type,
-                                                IWineD3DSurface **ppBackBuffer) {
-    IWineD3DDeviceImpl *This = (IWineD3DDeviceImpl *)iface;
-    IWineD3DSwapChain *swapChain;
+static HRESULT WINAPI IWineD3DDeviceImpl_GetBackBuffer(IWineD3DDevice *iface, UINT swapchain_idx,
+        UINT backbuffer_idx, WINED3DBACKBUFFER_TYPE backbuffer_type, IWineD3DSurface **backbuffer)
+{
+    IWineD3DSwapChain *swapchain;
     HRESULT hr;
 
-    TRACE("(%p) : BackBuf %d Type %d SwapChain %d returning %p\n", This, BackBuffer, Type, iSwapChain, *ppBackBuffer);
+    TRACE("iface %p, swapchain_idx %u, backbuffer_idx %u, backbuffer_type %#x, backbuffer %p.\n",
+            iface, swapchain_idx, backbuffer_idx, backbuffer_type, backbuffer);
 
-    hr = IWineD3DDeviceImpl_GetSwapChain(iface,  iSwapChain, &swapChain);
-    if (hr == WINED3D_OK) {
-        hr = IWineD3DSwapChain_GetBackBuffer(swapChain, BackBuffer, Type, ppBackBuffer);
-            IWineD3DSwapChain_Release(swapChain);
-    } else {
-        *ppBackBuffer = NULL;
+    hr = IWineD3DDeviceImpl_GetSwapChain(iface, swapchain_idx, &swapchain);
+    if (FAILED(hr))
+    {
+        WARN("Failed to get swapchain %u, hr %#x.\n", swapchain_idx, hr);
+        return hr;
     }
-    return hr;
+
+    hr = IWineD3DSwapChain_GetBackBuffer(swapchain, backbuffer_idx, backbuffer_type, backbuffer);
+    IWineD3DSwapChain_Release(swapchain);
+    if (FAILED(hr))
+    {
+        WARN("Failed to get backbuffer %u, hr %#x.\n", backbuffer_idx, hr);
+        return hr;
+    }
+
+    return WINED3D_OK;
 }
 
 static HRESULT WINAPI IWineD3DDeviceImpl_GetDeviceCaps(IWineD3DDevice *iface, WINED3DCAPS* pCaps) {