There is a problem in v 1.90.? about color. Please have a look at the code below.
This should show a yellowish square on a green background, but we see
blue noise. It happens even with opacity=1.
It becomes fine with blendMode=‘avg’, or useFBO=False.
I wonder if this problem is already investigated.
I’ve found the same problem on Mac (10.13.4) and Win 10. Previous versions seem
to be no problem on the same Mac.
I have several options to avoid it, by using an older version or ‘avg’ mode (with opacity
=1, I suppose it does not have any effect.), but I also wonder what is the actual
impact of useFBO=False.
from psychopy import visual, core win = visual.Window( size=[800,800], fullscr=False, screen=0, allowGUI=False, allowStencil=False, monitor=u'testMonitor', color=[-1,0,-1], colorSpace='rgb', blendMode='add', useFBO=True) polygon = visual.Rect( win=win, name='polygon',units='height', width=(0.2,0.2), height=(0.2,0.2), ori=0, pos=[0,0], lineWidth=0, fillColor=[1,-1,-1], fillColorSpace='rgb', opacity=0.5) polygon.draw() win.flip() core.wait(1.0) win.close() core.quit()