I have a code that presents letters in four orientations (0, 90, 180, 270). The orientation of each letter is specified in an Excel file that PsychoPy reads in. However, the displays look different when the code runs locally on PsychoPy, versus when it runs online in Pavlovia. Basically, a 90-deg orientation when run locally appears as a 270-deg orientation when run online. This is a problem because the task is to report a target letter’s orientation. Attached are two images of the same trial, one rendered locally, the other online. What might have led to this difference?
Ah, that’s a matter of convention. I’m afraid PsychoPy doesn’t always follow conventions and here I think it’s tripped us up. PsychoPy treats orientation like a clock with 0 at the top and getting larger going clockwise but engineers and software typically uses orientation from polar coords, with 0 to the right, increasing going anti-clockwise. I think we’d better change the online version to fit the unconventional Python format.