Psychtoolbox>Screen.{mex*} subfunction

Screen(‘glPoint’, windowPtr, color, x, y [,size]);

Draw a point at the specified location ‘x’, ‘y’ with the requested optional
diameter ‘size’ in the requested ‘color’. For drawing of many points, e.g.,
random dot fields, use Screen(‘DrawDots’) instead.

###See also: FrameRect