 		private var _postProcessingScene		: Scene			= null;
 		private var _postProcessingProperties	: DataProvider	= new DataProvider();
 		
+		private var _lastViewportWidth			: Number		= 0;
+		private var _lastViewportHeight			: Number		= 0;
+		
 		/**
 		 * Index meshes by their own databinding.
 		 *   * this is required to handle meshBindings.properyChange without

			context.enableErrorChecking = (Minko.debugLevel & DebugLevel.CONTEXT) != 0;
			
			// sort passes
			if (!_passesAreSorted && numPasses != 0)
			{
				for (i = 0; i < numPasses; ++i)
					sortValues[i] = -(_passes[i] as ShaderInstance).settings.priority;

												target 		: BitmapData,
												time		: Number) : void
		{
			var viewportWidth	: Number = viewport.width;
			var viewportHeight	: Number = viewport.height;
			
			_scene.properties.setProperty("time", time);
			
			if (viewportWidth != _lastViewportWidth)
				_scene.properties.setProperty('viewportWidth', viewport.width);
			
			if (viewportHeight != _lastViewportHeight)
				_scene.properties.setProperty('viewportHeight', viewport.height);
			
			_lastViewportWidth	= viewportWidth;
			_lastViewportHeight	= viewportHeight
		}
		
		private function sceneExitFrameHandler(scene 	: Scene,
