Btw, the demo has triple buffering enabled by default. Triple buffering creates an initial speed hit dropping fps from 250 to around 70fps, but maintains speeds 2-3x higher when lots of blending is going on. Triple buffering isn't part of the system, it is just coded into the demo. The system can write to any buffer, so when I enable triple buffering I just tell it to write to the appropriate buffer.
The reason triple buffering speeds up blending operations is because it's faster to read pixels from managed images (which are buffered in ram) than it is to read pixels directly from vram.
The reason triple buffering speeds up blending operations is because it's faster to read pixels from managed images (which are buffered in ram) than it is to read pixels directly from vram.