ElementArrayStim - multiple regular polygons, rather than circles?

cookdj0128 · March 6, 2017, 7:54pm

About the ElementArrayStim function:
Is there a way to make the circles hexagons, triangles, pentagons, etc.?
Thanks!

Michael · March 6, 2017, 8:35pm

The help page (http://www.psychopy.org/api/visual/elementarraystim.html) doesn’t seem to be comprehensive for this stimulus, but check below for documentation on the elementTex parameter:

github.com

psychopy/psychopy/blob/master/psychopy/visual/elementarray.py#L678


        L = (-self.sfs[:, 0] * self.sizes[:, 0] / 2
             - self.phases[:, 0] + 0.5)
        R = (+self.sfs[:, 0] * self.sizes[:, 0] / 2
             - self.phases[:, 0] + 0.5)
        T = (+self.sfs[:, 1] * self.sizes[:, 1] / 2
             - self.phases[:, 1] + 0.5)
        B = (-self.sfs[:, 1] * self.sizes[:, 1] / 2
             - self.phases[:, 1] + 0.5)


    # self._texCoords=numpy.array([[1,1],[1,0],[0,0],[0,1]],
    #           'd').reshape([1,4,2])
    self._texCoords = (numpy.concatenate([[R, B], [L, B], [L, T], [R, T]])
        .transpose().reshape([N, 4, 2]).astype('d'))
    self._texCoords = numpy.ascontiguousarray(self._texCoords)
    self._needTexCoordUpdate = False


@attributeSetter
def elementTex(self, value):
    """The texture, to be used by all elements (e.g. 'sin', 'sqr',.. ,
    'myTexture.tif', numpy.ones([48,48])). Avoid this
    during time-critical points in your script. Uploading new textures

cookdj0128 · March 6, 2017, 9:52pm

Hi Michael,
thanks for the quick reply. For a hexagon, I was thinking that I might define an 256 by 256 zero array, with 1s in the array where my edges should be. Then, I’d use that for my texture, but I’m not sure if that’s what you’re also suggesting (conceptually at least). Can you confirm?
Thanks.

Michael · March 7, 2017, 3:11am

You’re exposing me a bit here as I’ve never used this myself, so the best I can say is “I think so”.

jon · March 7, 2017, 8:15am

Yes, you could do this by creating an array if you need to do it programmatically (I wouldn’t know how to draw a pentagon programmatically in an array).
Or just create png images of the shapes in some image editor? Seems way easier to me
Jon

cookdj0128 · March 7, 2017, 11:18am

Hi Michael, thanks!, Hi Jon, yes, it definitely is easier. I have found a good solution using .png images instead. For the fun of it, I may still figure out how to programmatically do polygons in arrays I will share if I finish!

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ElementArrayStim - multiple regular polygons, rather than circles?

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