I would like to draw a number of gratings on a background that is darker than 0 (in Psychopy’s [-1, 1] convention) luminance. I need to be able to manipulate the contrast of these gratings from trial to trial. I want the mean luminance to be constant across the window, so the contrast needs to change the span of the grating luminance around the background value (pedestal) My understanding is that this is not currently possible out of the box in Psychopy.
I’m willing to do some hacking to get the same functionality in
ElementArrayStim, but I’m not exactly sure where to start. The
PedestalGratingStim seems to work mainly by overriding the
_updateListShaders method, but this method does not exist for
Can you please give me some hints for how to apply the solution in
PedestalGratingStim to make a