Stop flickering!

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Dave	Dave posted 14 Years Ago Post Details Share Post
Group: Administrators Posts: 12K, Visits: 98K	We set up an experiment where most of the screen contents remain constant across the whole experiment, while only a few stimuli are rotated, sized, moved or replaced during trials. Needless to say, regarding the topic of this thread, we cannot have flicker between stimulus alterations. Subjects have to respond to certain changes and are also entitled to trigger specific events. Due to the dynamic nature of the changes we need to enforce a "one trial, one transformation" strategy to allow for realtime subject responses and immediate reactions to these responses. The transformations themselves require a lot of erasing, depending on size and shape of the stimuli. It would have been very helpful if the erase-feature was available but blank occluders will do the trick, too. In such cases, it usually helps to use the '/ erase' settings and your "occluders" smartly / efficiently. As an example, consider the two attached scripts. ~Dave Attachments HappyTrails.zip (442 views, 3.00 KB)
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Blackadder	Blackadder posted 14 Years Ago Post Details Share Post
Group: Forum Members Posts: 280, Visits: 147	NIfty scripting! The "erase" setting is entirely out of the picture in our case since a stimulus will be replaced with another stimulus in any instance, rather than with a blank area. Setting "erase" to true will yield flicker in such cases, hence we must rely on blank shapes. Bye, Malte.
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Dave	Dave posted 14 Years Ago Post Details Share Post
Group: Administrators Posts: 12K, Visits: 98K	Well, then the only practical help I can offer is to assist you in optimizing your script's setup, i.e. finding ways to keep the number of required occluders / blank shapes as low as possible. Let me know and I'll be here to help. Cheers, ~Dave
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Blackadder	Blackadder posted 14 Years Ago Post Details Share Post
Group: Forum Members Posts: 280, Visits: 147	Thanks Dave, the script is already done. I've decided to go with a set of small blank shapes and calculate their positions to occlude an arbitrarily sized area. Works well. Bye, Malte.
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