Delay in sketchpad display in Loop
I'm building an experiment with Open sesame. In this experiment, I would like to display one stimulus (a circle or a square) every 500ms. I would like display 20 stimuli. The participant have to determine if the stimulus is a circle (to press "S" key) or a square (to press "L" key).
The localization of the stimulus on the screen is random and the alternating between square and circle is also random. For this, I created a loop. Each row is the name of the stimulus (circle/square), a x position, and a y position. The order of the loop is "random".
Next, I added a sketchpad which displays the stimuli according to the values of variables in the loop. Finally, the function keyboard.get_key( ) to record the responses.
Because I would like to display 20 stimuli (one by one), my loop iterates 20 times (until the count_variable = 20). So, the total time of this display must be 10 s (20 stimuli * 500 ms). However, this display runs late (12s instead of 10s). I don't understand why. Can you help me to reduce this late?
You could find tattached this opensesame projet (Distracteur_display.osexp).
I tried to not use "sketchpad" but canvas or form (with inline script python) but the issue is the same.
I tried to use letter instead of square/circle but the issue is the same.
I verified to correctly use "prepare" for the keyboard.
Thanks you for your help!
NB: I'm using the backend "PsychoPy, powerful stimulusgeneration"