Depths between two element array stim objects

Coding
1

I’m trying to make an array of complex objects that are composed of two solid vertical bars and a drifting grating in between. See the screenshot below:

image
image1537×911 161 KB

However, because i’ve coded the vertical bars and the drifting gratings as two separate element array stim objects, the vertical bars are all on top of every drifting grating - this is not ideal because the associated bars and gratings should be considered a unitary “object”. Is there a way to interleave the depths between two element array stim objects? I have tried defining “depths”, but the error message I get is:

Traceback (most recent call last):
  File "C:\Users\andre\Desktop\moving mondrian.py", line 24, in <module>
    bars = visual.ElementArrayStim(window, nElements = numPieces*2, elementTex = None, elementMask = None, units = 'deg', sizes = [.2,1], xys = positionsBars, colors = colors, depths = depthBars)
  File "C:\Program Files\PsychoPy\lib\site-packages\psychopy\contrib\lazy_import.py", line 120, in __call__
    return obj(*args, **kwargs)
  File "C:\Program Files\PsychoPy\lib\site-packages\psychopy\visual\elementarray.py", line 163, in __init__
    self._updateVertices()
  File "C:\Program Files\PsychoPy\lib\site-packages\psychopy\visual\elementarray.py", line 614, in _updateVertices
    verts[:, 2] = self.depths + self.fieldDepth
TypeError: can only concatenate list (not "int") to list

This happens whether I give the depths paramater a list of numbers (for example, [0,1,2,3,4]), or a list of list of numbers (for example, [[0],[1],[2],[3]]. I also see that the “depth” parameter is pretty much depreciated across the board.

Is there any way to accomplish what I’m trying to accomplish with element array stim? If I could specify different textures/masks for each element then that would work as well. Ultimately, what I want to create is a complex object that has a drifting grating sandwiched between two stationary bars, and I want that complex object to be randomly tiled across the screen.

Here is my current example code. Note that I haven’t made the gratings drift yet.

from psychopy import visual,core
import numpy, random


numPieces = 20
pieceSize = 50



window = visual.Window(fullscr = False)

depthGratings = list(range(numPieces))
positionsGratings = (numpy.random.random(size = [numPieces,2]) * 300) - 150

positionsLeftBar = positionsGratings - [.5*pieceSize, 0]
positionsRightBar = positionsGratings + [.5*pieceSize, 0]
positionsBars = numpy.concatenate((positionsLeftBar, positionsRightBar),axis = 0)
depthBars = depthGratings + depthGratings

colors = [[1,1,1],[-1,-1,-1]] * numPieces
random.shuffle(colors)
colors = numpy.array(colors)

bars = visual.ElementArrayStim(window, nElements = numPieces*2, elementTex = None, elementMask = None, units = 'pix', sizes = [.1*pieceSize,pieceSize], xys = positionsBars, colors = colors)#, depths = depthBars)
gratings = visual.ElementArrayStim(window, nElements = numPieces, elementTex = 'sqr', elementMask = None, units = 'pix', sizes = [pieceSize,pieceSize], xys = positionsGratings, colors = [.2,.2,.2], sfs = 4)#, depths = depthGratings)

gratings.draw()
bars.draw()
window.flip()

core.wait(5)