diff --git a/scene.cpp b/scene.cpp
index 4d4f86813b..d780a5659f 100644
--- a/scene.cpp
+++ b/scene.cpp
@@ -41,6 +41,21 @@ Scene::~Scene()
     {
     }
 
+// returns mask and possibly modified region
+void Scene::paintScreen( int* mask, QRegion* region )
+    {
+    *mask = ( *region == QRegion( 0, 0, displayWidth(), displayHeight()))
+        ? 0 : PAINT_SCREEN_REGION;
+    WrapperEffect wrapper;
+    // preparation step
+    effects->prePaintScreen( mask, region, &wrapper );
+    if( *mask & ( PAINT_SCREEN_TRANSFORMED | PAINT_WINDOW_TRANSFORMED ))
+        *mask &= ~PAINT_SCREEN_REGION;
+    // TODO call also prePaintWindow() for all windows
+    ScreenPaintData data;
+    effects->paintScreen( *mask, *region, data, &wrapper );
+    }
+
 void Scene::WrapperEffect::prePaintScreen( int*, QRegion* )
     {
     // nothing, no changes
diff --git a/scene.h b/scene.h
index 1222b22406..16775f8f3c 100644
--- a/scene.h
+++ b/scene.h
@@ -46,6 +46,7 @@ class Scene
             PAINT_SCREEN_TRANSFORMED    = 1 << 4
             };
     protected:
+        void paintScreen( int* mask, QRegion* region );
         virtual void paintGenericScreen( int mask, ScreenPaintData data );
         virtual void paintSimpleScreen( int mask, QRegion region );
         virtual void paintBackground( QRegion region ) = 0;
diff --git a/scene_opengl.cpp b/scene_opengl.cpp
index d151099ba6..968308790b 100644
--- a/scene_opengl.cpp
+++ b/scene_opengl.cpp
@@ -277,16 +277,8 @@ void SceneOpenGL::paint( QRegion damage, ToplevelList toplevels )
     glClear( GL_COLOR_BUFFER_BIT );
     glScalef( 1, -1, 1 );
     glTranslatef( 0, -displayHeight(), 0 );
-    int mask = ( damage == QRegion( 0, 0, displayWidth(), displayHeight()))
-        ? 0 : PAINT_SCREEN_REGION;
-    WrapperEffect wrapper;
-    // preparation step
-    effects->prePaintScreen( &mask, &damage, &wrapper );
-    if( mask & ( PAINT_SCREEN_TRANSFORMED | PAINT_WINDOW_TRANSFORMED ))
-        mask &= ~PAINT_SCREEN_REGION;
-    // TODO call also prePaintWindow() for all windows
-    ScreenPaintData data;
-    effects->paintScreen( mask, damage, data, &wrapper );
+    int mask = 0;
+    paintScreen( &mask, &damage );
     stacking_order.clear();
     glPopMatrix();
     // TODO only partial repaint for mask & PAINT_SCREEN_REGION
diff --git a/scene_xrender.cpp b/scene_xrender.cpp
index caefb8e8a7..32fb34acd0 100644
--- a/scene_xrender.cpp
+++ b/scene_xrender.cpp
@@ -84,16 +84,8 @@ void SceneXrender::paint( QRegion damage, ToplevelList toplevels )
         assert( windows.contains( c ));
         stacking_order.append( &windows[ c ] );
         }
-    int mask = ( damage == QRegion( 0, 0, displayWidth(), displayHeight()))
-        ? 0 : PAINT_SCREEN_REGION;
-    WrapperEffect wrapper;
-    // preparation step
-    effects->prePaintScreen( &mask, &damage, &wrapper );
-    if( mask & ( PAINT_SCREEN_TRANSFORMED | PAINT_WINDOW_TRANSFORMED ))
-        mask &= ~PAINT_SCREEN_REGION;
-    // TODO call also prePaintWindow() for all windows
-    ScreenPaintData data;
-    effects->paintScreen( mask, damage, data, &wrapper );
+    int mask = 0;
+    paintScreen( &mask, &damage );
     stacking_order.clear();
     if( mask & PAINT_SCREEN_REGION )
         {