I hope this isn’t answered elsewhere and I missed it, but I’m having doing trouble doing something I thought would be simple. I’m using PsychoPy version 1.90.3 for Python 2.7, under Windows 7.
In my experiment, I want participants to make a categorization judgement, and get feedback about their accuracy. I thought I would do this by drawing the stimulus to be categorized to the screen, and then after the judgement was made, add some text telling them correct vs. incorrect. This simple example below describes what I want to happen:
from psychopy import core, visual win = visual.Window([400, 300]) # This text should appear along on the screen for 2 seconds message1 = visual.TextStim(win, text="Greetings.") message1.draw() win.flip() core.wait(2.0) # This text should then be *added* to the screen along with the "Greetings" text message2 = visual.TextStim(win, text="My name is Hal 9000", pos=(0,-.25)) message2.draw() win.flip() core.wait(2.0) win.close() core.quit()
But instead, what happens is the second message appears by itself. In Psychtoolbox-land, I would add the second message to the screen by asking it to not clear the back buffer when “flipping” the stimuli to the screen. But in PsychoPy-world, I can only choose not the clear the front buffer when flipping.
Is there any way I can add to what is on the screen currently? I’d rather like to avoid redrawing the entire contents of the screen after each flip. If I’m forced to overwrite the back buffer, is there any way I can copy the front buffer to the back buffer without “flipping” the two?
EDIT: Am I going to have to abuse auto-drawing here?
Thanks in advance for the guidance.