DrawFixationMark.m

function [ HW ] = DrawFixationMark( HW, loc, fixWidthPx, fixLineWidthPx )
%DRAWFIXATIONMARK Draws a fixation mark with nonius lines into a stereo
%view
%   loc = center of mark
%   fixWidthPx = width of fixation box, in pixels
%   fixLineWidthPx = line width fixation box and lines
%   
% TODO parameterize locations of Nonius lines?

for eye = [0 1]
    HW = ScreenCustomStereo(...
        HW, 'SelectStereoDrawBuffer', HW.winPtr, eye);
    
    Screen('FrameRect', HW.winPtr, HW.white, ...
        [loc-0.5*fixWidthPx, loc+0.5*fixWidthPx], ...
        fixLineWidthPx);
    
    if eye == 0
        Screen('DrawLine', HW.winPtr, ...
            HW.white, loc(1), loc(2)-0.75*fixWidthPx,  ...
            loc(1), loc(2)-1.5*fixWidthPx, fixLineWidthPx);
        Screen('DrawLine', HW.winPtr, ...
            HW.white, loc(1)-0.75*fixWidthPx, loc(2),  ...
            loc(1)-1.5*fixWidthPx, loc(2), fixLineWidthPx);
    else
        Screen('DrawLine', HW.winPtr, ...
            HW.white, loc(1), loc(2)+0.75*fixWidthPx,  ...
            loc(1), loc(2)+1.5*fixWidthPx, fixLineWidthPx);
        Screen('DrawLine', HW.winPtr, ...
            HW.white, loc(1)+0.75*fixWidthPx, loc(2),  ...
            loc(1)+1.5*fixWidthPx, loc(2), fixLineWidthPx);
    end
end

end