purpose: sets the background color
usage: mglClearScreen(<color>)

set to the level of gray (0-1)

mglClearScreen(gray)

set to the given [r g b]

mglClearScreen([r g b])

full example

mglOpen;
mglClearScreen([0.7 0.2 0.5]);
mglFlush();

purpose: plot 2D points on an OpenGL screen opened with mglOpen. For round dots, use mglGluDisk.
usage: mglPoints2(x,y,size,color)

mglOpen;
mglVisualAngleCoordinates(57,[16 12]);
mglPoints2(16*rand(500,1)-8,12*rand(500,1)-6,2,1);
mglFlush

purpose: plot 3D points on an OpenGL screen opened with mglOpen
usage: mglPoints2(x,y,z,size,color)

mglOpen;
mglVisualAngleCoordinates(57,[16 12]);
mglPoints3(16*rand(500,1)-8,12*rand(500,1)-6,zeros(500,1),2,1);
mglFlush

purpose: mex function to plot lines on an OpenGL screen opened with glopen
usage: mglLines(x0, y0, x1, y1,size,color)

mglOpen
mglVisualAngleCoordinates(57,[16 12]);
mglLines2(-4, -4, 4, 4, 2, [1 0.6 1]);
mglFlush

purpose: draw filled oval(s) centered at x,y with size [xsize ysize] and color [rgb]. the function is vectorized, so if you provide many x/y coordinates (identical) ovals will be plotted at all those locations.
usage: mglFillOval(x,y, size, color)

mglOpen;
mglVisualAngleCoordinates(57,[16 12]);
x = [-1 -4 -3 0 3 4 1];
y = [-1 -4 -3 0 3 4 1];
sz = [1 1];
mglFillOval(x, y, sz,  [1 0 0]);
mglFlush();

purpose: draw filled rectangles(s) centered at x,y with size [xsize ysize] and color [rgb]. the function is vectorized, so if you provide many x/y coordinates (identical) ovals will be plotted at all those locations.
usage: [ ] = mglFillRect(x,y, size, color)

mglOpen;
mglVisualAngleCoordinates(57,[16 12]);
x = [-1 -4 -3 0 3 4 1];
y = [-1 -4 -3 0 3 4 1];
sz = [1 1];
mglFillRect(x, y, sz,  [1 1 0]);
mglFlush();

purpose: draws a fixation cross. With no arguments, draws a fixation cross at origin (default width 0.2 with linewidth 1 in white at [0,0])
usage: mglFixationCross([width], [linewidth], [color], [origin]);
alternate usage: mglFixationCross( params )

mglOpen;
mglVisualAngleCoordinates(57,[16 12]);
mglFixationCross;
mglFlush;

purpose: for annuli and rings, e.g. for retinotopic stimuli. The function is vectorized, such that multiple annuli can be rendered in one call. In this case, x,y, isize, and osize need to have the same number of elements. Color is also vectorized.
usage: [ ] = mglGluAnnulus( x, y, isize, osize, color, [nslices], [nloops] )

 mglOpen(0);
 mglVisualAngleCoordinates(57,[16 12]);
 x = zeros(4, 1);
 y = zeros(4, 1);
 isize = linspace(1, 8, 4);
 osize = isize+linspace(0.1, 2, 4);
 colors = jet(4)';
 mglGluAnnulus(x, y, isize, osize,colors , 60, 2);
 mglFlush();

purpose: for plotting circular (rather than square dots), use this function. on slower machines, large number of dots may lead to dropped frames. there may be a way to speed this up a bit in future.
usage: [ ] = mglGluDisk( x, y, size, color, [nslices], [nloops] )

mglOpen;
mglVisualAngleCoordinates(57,[16 12]);
x = 16*rand(100,1)-8;
y = 12*rand(100,1)-6;
mglGluDisk(x, y, 0.1,  [0.1 0.6 1], 24, 2);
mglFlush();

purpose: for segments and wedges, e.g. for retinotopic stimuli. The function is vectorized, such that multiple segments can be rendered in one call. In this case, x,y, isize, osize, startAngles, and sweepAngles need to have the same number of elements. Color is also vectorized (see mglGluAnnulus and the example below).
usage: [ ] = mglGluPartialDisk( x, y, isize, osize, startAngles, sweepAngles, color, [nslices], [nloops] )

mglOpen(0);
mglVisualAngleCoordinates(57,[16 12]);
x = zeros(10, 1);
y = zeros(10, 1);
isize = linspace(1, 5, 10);
osize = 3+isize;
startAngles = linspace(0,180, 10)
sweepAngles = ones(1,10).*10;
colors = jet(10)';
mglGluPartialDisk(x, y, isize, osize, startAngles, sweepAngles, colors, 60, 2);
mglFlush();

purpose: mex function to draw a polygon in an OpenGL screen opened with mglOpen. x and y can be vectors (the polygon will be closed)
usage: mglPolygon(x, y, [color])

mglOpen;
mglVisualAngleCoordinates(57,[16 12]);
x = [-5 -6 -3  4 5];
y = [ 5  1 -4 -2 3];
mglPolygon(x, y, [1 0 0]);
mglFlush();

usage: mglQuad( vX, vY, rgbColor, [antiAliasFlag] );
purpose: mex function to draw a quad in an OpenGL screen opened with mglOpen

mglOpen;
mglScreenCoordinates
mglQuad([100; 600; 600; 100], [100; 200; 600; 100], [1; 1; 1], 1);
mglFlush();