>Psychtoolbox>PsychDemos

AlphaRotateDemo(numFrames, ifis)

numFrames Number of grating textures to use for the drifting grating…

ifis = Number of monitor refreshes to wait between drawing single
textures…

OS X: ___________________________________________________________________

Display a rotating grating using the new Screen(‘DrawTexture’) command.
In the OS X Psychtoolbox Screen(‘DrawTexture’) replaces
Screen(‘CopyWindow’).

This illustrates an application of Alpha blending by masking the rotating
grating with a gaussian transparency mask.

In each frame, first the grating is drawn. Then a texture acting as a
transparency mask is drawn “over” the grating, masking out selected
parts of the grating.

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see also: PsychDemos, MovieDemo