wined3d: Don't render single buffered swapchains to a FBO.

dlls/wined3d/device.c

@@ -6527,8 +6527,13 @@ static HRESULT WINAPI IWineD3DDeviceImpl_Reset(IWineD3DDevice* iface, WINED3DPRE
         RECT client_rect;
         GetClientRect(swapchain->win_handle, &client_rect);
 
-        if(swapchain->presentParms.BackBufferWidth != client_rect.right ||
-           swapchain->presentParms.BackBufferHeight != client_rect.bottom)
+        if(!swapchain->presentParms.BackBufferCount)
+        {
+            TRACE("Single buffered rendering\n");
+            swapchain->render_to_fbo = FALSE;
+        }
+        else if(swapchain->presentParms.BackBufferWidth  != client_rect.right  ||
+                swapchain->presentParms.BackBufferHeight != client_rect.bottom )
         {
             TRACE("Rendering to FBO. Backbuffer %ux%u, window %ux%u\n",
                     swapchain->presentParms.BackBufferWidth,

dlls/wined3d/swapchain.c

@@ -739,6 +739,7 @@ HRESULT swapchain_init(IWineD3DSwapChainImpl *swapchain, WINED3DSURFTYPE surface
     swapchain->presentParms = *present_parameters;
 
     if (wined3d_settings.offscreen_rendering_mode == ORM_FBO
+            && present_parameters->BackBufferCount
             && (present_parameters->BackBufferWidth != client_rect.right
             || present_parameters->BackBufferHeight != client_rect.bottom))
     {