#! /usr/local/bin/python2.5
"""
There are many ways to generate counter-phase e.g.
vary the contrast of a grating sinusoidally between 1 and -1,
take 2 gratings in opposite phase overlaid and vary the
opacity of the upper one between 1:0, or take 2 gratings
overlaid with the upper one of 0.5 opacity and drift them
in opposite directions.
This script takes the first approach as a test of how fast
contrast textures are being rewritten to the graphics card
"""
from psychopy import core,visual,event
from numpy import sin,pi
#create a window to draw in
myWin = visual.Window((600,600.0), allowGUI=False, monitor='testMonitor', units='deg')
#INITIALISE SOME STIMULI
grating1 = visual.PatchStim(myWin,tex="sin",mask="circle",texRes=128,
rgb=[1.0,1.0,1.0],opacity=1.0,
size=(5.0,5.0), sf=(2.0,2.0),
ori = 45, depth=0.5)
message = visual.TextStim(myWin,text='Hit Q to quit',
pos=(-0.95,-0.95),units='norm',
alignVert='bottom',alignHoriz='left')
trialClock = core.Clock()
t = lastFPSupdate = 0
while t<20:#quits after 20 secs
t=trialClock.getTime()
grating1.setContrast(sin(t*pi*2))
grating1.draw() #redraw it
message.draw()
myWin.flip() #update the screen
#handle key presses each frame
for keys in event.getKeys():
if keys in ['escape','q']:
myWin.close()
core.quit()
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