Flicker fusion task

# This script shows two patches in rapid succession, to get a flicker fusion
# effect. It requires the PsychoPy backend.

from psychopy import visual
from openexp.keyboard import keyboard
import numpy as np

size = 512 # Stimulus size
n = 50 # Number of presentation cycles
delay = 20 # Delay between presentations (the actual delay depends on the
           # display refresh as well!)

# Initial colors in HSV color space. See http://www.psychopy.org/general/colours.html
col1 = [0,1,.5]
col2 = [180,1,.5]
colD = .005 # Luminance change per step


my_keyboard = keyboard(self.experiment, keylist=["up", "down", 'space'],
    timeout=1)

# Create two stimuli, see
# http://www.psychopy.org/api/visual/patchstim.html
patch1 = visual.PatchStim(win, tex=None, mask='gauss', color=col1,
    size=size, colorSpace='hsv')
patch2 = visual.PatchStim(win, tex=None, mask='gauss', color=col2,
    size=size, colorSpace='hsv')

# Alternately show the stimuli. Also record the timestamps, so we can verify
# the timing
l = []
while True:

    # Accept when space is pressed, and use up and down to calibrate colors
    resp, time = my_keyboard.get_key()
    if resp == 'space':
        break
    if resp == 'up':
        col1[2] = max(0, min(1, col1[2]+colD))
        col2[2] = max(0, min(1, col2[2]-colD))
        patch1.setColor(col1)
        patch2.setColor(col2)
    if resp == 'down':
        col1[2] = max(0, min(1, col1[2]-colD))
        col2[2] = max(0, min(1, col2[2]+colD))
        patch1.setColor(col1)
        patch2.setColor(col2)

    # Show the two patches
    patch1.draw()
    win.flip()
    self.sleep(delay)
    l.append(self.time())
    patch2.draw()
    win.flip()
    l.append(self.time())
    self.sleep(delay)

    l = l[-100:] # Make sure the list doesn't grow too long

# Store the actual delay between the two stimuli, and the standard deviation
# of the delay for offline verification
a = np.array(l)
exp.set('mean_soa', np.mean(a[1:]-a[:-1]))
exp.set('sd_soa',  np.std(a[1:]-a[:-1]))

exp.set('col1', '%s' % col1)
exp.set('col2', '%s' % col2)