View Full Version : Extending lines

04-12-2001, 09:17 AM
Here's my dilemma - I have a bunch of line segments that form a smooth contour. I cannot guarantee the drawing order of the segments, so I must draw them each end-to-end individually. I am ending up with 1 pixel gaps between many of the segments, probably due to slight floating point imprecisions in the calculations for the points. Is there a facility in OpenGL to automatically extend the length of the lines by a pixel on either end, or something that will have the same effect?

Obviously, I could do this manually, but I thought that perhaps GL would have something that might be faster...


04-12-2001, 09:34 PM
garantee the order http://www.opengl.org/discussion_boards/ubb/smile.gif and use GL_LINE_STRIP

Michael Steinberg
04-13-2001, 11:57 PM
I had this problem and it is not really due to floating point imprecisions. It is the way the fragments get calculated. A fragment has to at least cover 50% of a pixel to get drawn as I believe. So you need to make your lines a little bit longer than they actually are. to guarantee that the first fragment and the last take up the pixel.