Updated CSFML and SFML.Net in the sfml2 branch

git-svn-id: https://sfml.svn.sourceforge.net/svnroot/sfml/branches/sfml2@1233 4e206d99-4929-0410-ac5d-dfc041789085

dotnet/samples/opengl/OpenGL.cs

@@ -16,6 +16,9 @@ namespace sample_opengl
             // Create main window
             RenderWindow window = new RenderWindow(new VideoMode(800, 600), "SFML.Net OpenGL");
 
+            // Activate it as the target for OpenGL calls
+            window.SetActive();
+
             // Setup event handlers
             window.Closed     += new EventHandler(OnClosed);
             window.KeyPressed += new EventHandler<KeyEventArgs>(OnKeyPressed);
@@ -72,6 +75,13 @@ namespace sample_opengl
                 // Draw background
                 window.Draw(background);
 
+                // Flush the window, to make sure that our OpenGL cube
+                // will be rendered on top of the background sprite
+                window.Flush();
+
+                // Activate the window for OpenGL calls
+                window.SetActive();
+
                 // Clear depth buffer
                 Gl.glClear(Gl.GL_DEPTH_BUFFER_BIT);
 
@@ -159,6 +169,8 @@ namespace sample_opengl
         /// </summary>
         static void OnResized(object sender, SizeEventArgs e)
         {
+            RenderWindow window = (RenderWindow)sender;
+            window.SetActive();
             Gl.glViewport(0, 0, (int)e.Width, (int)e.Height);
         }
     }