ManyRotatedMaskedTexturesDemo

Psychtoolbox › PsychDemos

ManyRotatedMaskedTexturesDemo([ngabors=200]) -- An aquarium full of cute little gratings!

This demo shows how to use the Screen('DrawTextures') command to draw a
large number of similar images quickly - in this case, grating patches of
different position, size and orientation. It also shows how to achieve
fast, mathematically correct, linear superposition of image patches by
use of alpha blending and the Psychtoolbox imaging pipeline. While you
could always achieve proper superposition by precomputing images in
Matlab, then drawing them as textures, the use of alpha blending allows
to offload the computations to your graphics hardware - this allows
speedups by factors of more than 100x.

The demo shows "an aquarium" of many little gabor patches, each moving
into a random direction. Sometimes the gabors intersect, in that case
you'll see a linear superposition of them.

Each frame of the animation contains 'ngabors' patches, ngabors defaults
to 200. You can exit the demo by pressing any key on the keyboard.

This demo needs recent graphics hardware with floating point framebuffer
support: ATI Radeon X1000 and later, NVidia GeForce 6000 and later.