getTriangle.m

function pointList = getTriangle(x, y, a, h, pointing)
    switch pointing
        case 'UpArrow' % upwards
            pointList   = round([x, y - h;
                x - a/2, y;
                x + a/2, y]);
        case 'DownArrow' % downwards
            pointList   = round([x, y + h;
                x - a/2, y;
                x + a/2, y]);
        case 'RightArrow' % right
            pointList   = round([x + h, y;
                x, y - a/2;
                x, y + a/2]);
        case 'LeftArrow' % left
            pointList   = round([x - h, y;
                x, y + a/2;
                x, y - a/2]);
    end
    % shift the triangle center of mass
    % to the center of the screen
    center      = mean(pointList);
    d           = [x, y] - center;
    pointList   = pointList + d;
end