View Full Version : Thick lines with glLineWidth()

12-15-2007, 03:24 PM
Hi All,

Is there a way to change the 'cutter blade like' shape of oblique thick lines? I mean the beginning and the end of the line.



12-15-2007, 05:13 PM
You'll have to use antialiasing, according to the GLspec:

Non-antialiased line segments of width other than one are rasterized by offsetting them in the minor direction (for an x-major line, the minor direction is y, and for a y-major line, the minor direction is x) and replicating fragments in the minor direction
Rasterized antialiased line segments produce fragments whose fragment squares intersect a rectangle centered on the line segment. Two of the edges are parallel to the specified line segment; each is at a distance of one-half the current width from
that segment: one above the segment and one below it. The other two edges pass through the line endpoints and are perpendicular to the direction of the specified line segment.


12-15-2007, 05:50 PM
Well, it can depend a lot of your hardware.

These tests have been done on a mac, but I guess it depends more on the card than on the OS :

01-11-2008, 11:58 PM
Thanks a lot guys. Now it is more clear to me. Very interesting also the FSAA link.