windows opengl: Transparency of the native widgets.

Change-Id: Ifa6ba5735582effc27ac68556c2367077705d1d6

vcl/win/source/gdi/salgdi.cxx

@@ -610,7 +610,7 @@ OpenGLTexture* OpenGLCompatibleDC::getTexture()
         return NULL;
 
     // turn what's in the mpData into a texture
-    return new OpenGLTexture(maRects.mnSrcWidth, maRects.mnSrcHeight, GL_RGBA, GL_UNSIGNED_BYTE, reinterpret_cast<sal_uInt8*>(mpData));
+    return new OpenGLTexture(maRects.mnSrcWidth, maRects.mnSrcHeight, GL_BGRA, GL_UNSIGNED_BYTE, reinterpret_cast<sal_uInt8*>(mpData));
 }
 
 WinSalGraphics::WinSalGraphics(WinSalGraphics::Type eType, bool bScreen, HWND hWnd):

vcl/win/source/gdi/salnativewidgets-luna.cxx

@@ -1297,7 +1297,7 @@ bool WinSalGraphics::drawNativeControl( ControlType nType,
                 return false;
 
             pImpl->PreDraw();
-            pImpl->DrawTexture(*pBlackTexture, aBlackDC.getTwoRect()); // FIXME combine the textures - DrawTextureSynthesizedAlpha()
+            pImpl->DrawTextureDiff(*pWhiteTexture, *pBlackTexture, aBlackDC.getTwoRect());
             pImpl->PostDraw();
 
             bOk = true;