[visionegg] Re: Who's using the Presentation class?

  • From: Simeon Fitch <simeon.fitch@xxxxxxxxxxxxx>
  • To: visionegg@xxxxxxxxxxxxx
  • Date: Mon, 23 Jan 2006 09:28:36 -0500

Eamon,

The Kubovy Lab @ UVa is doing what you describe (if I understand you
correctly) by using multiple presentation/viewport instances for each
component of each trial (all sharing the same screen). For example, in
one experiment we present:

1) A fixation spot
2) A mask
3) The stimulus
4) A response screen

Each of these is a stimulus tied to a Presentation and Viewport. A
"show()" convenience method has been added to each class to reset the
Presentation object and call its "go()" method.

The inner "loop" of this experiment looks something like this:
----------------------------
# Define the trials
conditions = setupTrialData(sequenceFileName)
breakNotice = Instructions(screen, "Take a moment to rest.")
for i, trial in enumerate(conditions):
    lattice.setTrial(trial)
    fixationPres.go()
    mask.show()
    lattice.show()
    response.show()
    logger.log(trial)

    if ((i+1) % session.breakInterval) == 0:
        breakNotice.show()
-------------------------------
The power of the Presentation object becomes apparent when you have
Stimulus parameters which change over time (e.g. a function of 't') or
between trials.

You are very welcome to download our source code and play with it
however you like. Instructions are available here:

http://kubovylab.psyc.virginia.edu/index.php/How_to_Get_The_Source_Code

For a quick sense on how we are using VisionEgg, some example screen
shots are available here:

http://kubovylab.psyc.virginia.edu/index.php/Main_Page

Along with instructions on how to get it running, if interested:

http://kubovylab.psyc.virginia.edu/index.php/Perception_Toolkit_Development_Environment_Setup

Good luck!

Simeon Fitch

--
Simeon H.K. Fitch, Owner
Mustard Seed Software
Charlottesville, VA  22901





On 1/23/06, Eamon Caddigan <ecaddiga@xxxxxxxx> wrote:
> Hi all,
>
> Our lab is getting ready to run its first experiments that make use
> of Vision Egg. They work well enough, but I've been unable to make
> use of the Presentation class for my main loop without the result
> feeling uncomfortably kludgey.
>
> I'm happy to write my own main loop. However, since the code I write
> now may be used by other people in the lab as we continue
> transitioning to Vision Egg, I want it to fall in line with the
> current best practices.
>
> I'd probably feel better about this if the examples distributed with
> Vision Egg included a multi-trial experiment.
>
> Thanks,
> Eamon Caddigan
>
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