title: webGL - Draw a line on a surface
body: <p>I have a three dimensional textured surface that I need to draw a colored line on.  This would be similar to drawing lines of latitude/longitude on a sphere.  Is there a simple way to draw a line onto this surface?  The best result I have gotten so far is calculating points along the surface and making those my line vertices but this seems a little buggy as there are places where the line shows well and places where it doesn't.  Also, if I use this method do I need to offset the line out from the surface or do something else so that they don't "overlap" and show the surface instead of the line?</p>