Hi PsychoPy Devs,
I’m coding some stimuli that require a raised cosine ramp transparency mask. For some reason (which I have since forgotten!), I set “useFBO” to False, and I have realised that this nudges RGB triplet up by one. The following code demonstrates it:
from psychopy import visual win = visual.Window(size=[800, 800], fullscr=False, screen=0 , allowGUI=False, allowStencil=True, useFBO=False, units="pix", checkTiming = True) myMask3 = visual.filters.makeMask(256, 'raisedCosine', center = (0,0),fringeWidth=0.15, radius=1) myMask3 = myMask3 * -1 surround_aperture = visual.GratingStim(win, units="pix", tex=None, mask=myMask3, size=200, \ color=(0,0,0), pos=(0,0), ori=0,\ texRes=1024, contrast = 1, opacity = 1) surround_aperture.draw() win.getMovieFrame(buffer="back") win.flip() win.saveMovieFrames("RDK_scrnsqht.bmp")
Here’s a screenshot(left), and another screenshot with a 227(white) - 228(black) threshold.
Not sure if I’ve done something wrong, or if it is a bug, but I thought you may like to know.
I’m running Psychopy V2020.1.2 in Python 3.7 using Win10. GPU is an AMD RX580.