>Psychtoolbox>PsychDemos>OpenGL4MatlabDemos

ShepardZoomDemo

This demo implements kind of a visual version of the Shepard tone
illusion. This is an infinite zoom, by use of an OpenGL technique called
“Spectral Texturing”, a clever way of blending multiple textures
with each other by use of alpha-blending…

You can find more information about the technique and stimulus at:
http://www.kyb.tuebingen.mpg.de/~berger/spectraltexturing/

The “Spectral Texturing” method was published as a sketch at Siggraph 2003:
http://doi.acm.org/10.1145/965400.965509
It was also demonstrated at VSS demo night 2004.

Feel free to use the stimulus for experiments, but please kindly tell
Daniel Berger how you use it: daniel.berger@tuebingen.mpg.de

The original code for this demo has been written by Daniel Berger in 2003.
The code has been adapted for use with the PsychToolbox by Mario Kleiner
in 2006.