I don’t think that opacity is being recognised on my Pi:
grate = visual.GratingStim(win=mywin, size=20, sf=0.8, contrast=0.3) mask = visual.GratingStim(win=mywin, size=20, sf=0.4, contrast=0.3, ori = 90, opacity=0.5) ..... grate.draw() mask.draw()
Only shows the mask on a Pi, but shows the plaid fine on a Intel Linux and Mac. Is this a known bug ? How to generate the plaid on the Pi ?