Hi there,

I’m trying to create two circular apertures on the same screen with moving dots inside.

I’m using Psychtoolbox version: 3.0.18 - Flavor: Manual Install and Windows 11 Pro Version 21H2 Build 22000.739

When I run the following:

% New random positions

dots.x.right.ang = (rand(1,dots.ndots)-.5)*dots.aperture.size(1)+dots.center.right(1);

dots.x.left.ang = (rand(1,dots.ndots)-.5)*dots.aperture.size(1)+dots.center.left(1);

dots.y.right.ang = (rand(1,dots.ndots)-.5)*dots.aperture.size(2)+dots.center.right(2);

dots.y.left.ang = (rand(1,dots.ndots)-.5)*dots.aperture.size(2)+dots.center.left(2);

% Use the equation of an ellipse to determine which dots fall inside.

gooddots.right = (dots.x.right.ang-dots.center.right(1)).^2/(dots.aperture.size(1)/2).^2 + (dots.y.right.ang-dots.center.right(2)).^2/(dots.aperture.size(2)/2).^2 < 1;

gooddots.left = (dots.x.left.ang-dots.center.left(1)).^2/(dots.aperture.size(1)/2).^2 + (dots.y.left.ang-dots.center.left(2)).^2/(dots.aperture.size(2)/2).^2 < 1;

% Dot positions in px

xyright = [dots.x.right.ang; dots.y.right.ang] .* ppd;

xyleft = [dots.x.left.ang; dots.y.left.ang] .* ppd;

xyrightgood = xyright .* gooddots.right;

xyleftgood = xyleft .* gooddots.left;

% Draw dots

Screen(‘DrawDots’, window, xyrightgood, dots.sizepx, dots.colour, dots.center.right, 1);

Screen(‘DrawDots’, window, xyleftgood, dots.sizepx, dots.colour, dots.center.left, 1);

it unfortunately only shows one dot on each side although my xy matrices contain 100 coordinates each (as they should since dots.ndots=100).

I just can’t figure out what’s wrong and would be very, very grateful for any and all help.

Thanks so much in advance!

philine