View Full Version : drawing fat lines
maybe this sounds a little bit stupid, but anyway...
with glLineWidth (or how this function was called again) you can set the thickness of lines. what i'm wondering is wether this is supported by (modern) graphics card. i ask because i tried to draw a few lines, and it was quite slow on my card (matrox g400)...
10-12-2000, 07:16 AM
MATROX G400 have good support of OpenGL, if problem update drivers. http://www.opengl.org/discussion_boards/ubb/smile.gif
10-12-2000, 07:34 AM
Remember that most 3d cards (apart from high end stuff) don't have line drawing in silicon. The drivers build the line out of a number of polygons. Apparently (or so I've been told) the number of polygons required is not always 2 (as you might think) because this wouldn't guarantee pixel coverage. I've been told that the poly count for lines can go up to as many as 6 polys for a single line (it could be more in fact), so the cost for drawing 1 line != the cost for drawing 1 poly. Could this be why your program seems to be running slowly ?
matrox and good opengl support ?
this makes me smile http://www.opengl.org/discussion_boards/ubb/smile.gif
i didn't know that, but it would explain a lot. actually i didn't draw a few lines, it was a whole bunch, and if each line makes several polys...well.
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