rval = kPsychNeedFastOffscreenWindows
Return a flag that you can pass to the ‘imagingmode’ parameter of
Screen(‘OpenWindow’) in order to request use of fast support for Offscreen windows.

If requested, Psychtoolbox will use an especially fast buffering scheme
to implement Offscreen windows. This can significantly speed up drawing
if you make heavy use of Offscreen windows.

It is part of the Psychtoolbox imaging pipeline and only works on modern
graphics hardware, e.g., ATI Radeon 9600 and later, NVidia GeforceFX 5000
and later. Check the Wiki for graphics hardware
recommendations and for a description of PTB’s image processing
capabilities. If you need to use older hardware, Offscreen windows will
still work, but at a significantly lower speed.

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