public void Update()
{
Int32Rect sourceArea = new Int32Rect(0, 0, 256, 256);
_renderer.Clear();
_renderer.Update(_gameObjectService.GetObjects((GameObjectType)GameObjectTypes.SelectedItem, (string)GameObjectGroups.SelectedItem), false);
_bitmap.Lock();
_bitmap.WritePixels(sourceArea, _renderer.GetRectangle(sourceArea), sourceArea.Width * 4, sourceArea.X, sourceArea.Y);
_bitmap.AddDirtyRect(sourceArea);
_bitmap.Unlock();
}