[visionegg] Re: Recording frame times
- From: Jens Peter Lindemann <jens.lindemann@xxxxxxxxxxxxxxxx>
- To: visionegg@xxxxxxxxxxxxx
- Date: Thu, 15 Sep 2011 10:40:08 +0200
Hi Kit,
I'd like to save the frame times during my code.
it might be redundant to code inside visionegg, but you can use a
function controller to collect the frame timestamps. See the attached
code example which prints the timestamps of all frames presented.
Best,
Jens.
#!/usr/bin/env python
"""Sinusoidal grating calculated in realtime."""
############################
# Import various modules #
############################
import VisionEgg
VisionEgg.start_default_logging(); VisionEgg.watch_exceptions()
from VisionEgg.Core import *
from VisionEgg.FlowControl import Presentation
from VisionEgg.Gratings import *
#####################################
# Initialize OpenGL window/screen #
#####################################
screen = get_default_screen()
######################################
# Create sinusoidal grating object #
######################################
stimulus = SinGrating2D(position = ( screen.size[0]/2.0,
screen.size[1]/2.0 ),
anchor = 'center',
size = ( 300.0 , 300.0 ),
spatial_freq = 10.0 / screen.size[0], # units of
cycles/pixel
temporal_freq_hz = 1.0,
orientation = 45.0 )
###############################################################
# Create viewport - intermediary between stimuli and screen #
###############################################################
viewport = Viewport( screen=screen, stimuli=[stimulus] )
#####################
# Record timestamps #
#####################
class ts_recorder(object):
def __init__(self):
# initialize the timestamp list
self.ts=[]
def record(self, t):
# append current time value to the list
self.ts.append(t)
def show(self):
# traverse list and print timestamps
for n in range(len(self.ts)):
print 'Frame ', n, ': ', self.ts[n], 's'
# create an object of that class
rec=ts_recorder()
########################################
# Create presentation object and go! #
########################################
p = Presentation(go_duration=(5.0,'seconds'),viewports=[viewport])
# register the record method bound to the "rec"
p.add_controller(None, None, FunctionController(during_go_func=rec.record))
p.go()
############################
# Display frame timestamps #
############################
rec.show()
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