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View Full Version : Is it possible to change line width somehow besides glLineWidth()?



Jackis
05-31-2006, 09:35 AM
As far as I know, OpenGL has no possibilities to vary linewidth via vertex shader, as points do (PSIZE register).

But sometimes this option may be very helpful.

Don't you know, are there some extensions on this?
Cause if no, I will use quads instead, but it would be twice harder for GPU in bandwidth and processing time cost, as if lines were suported in such a manner.

Thank you!

By the way, is it true, that:
"... many folks have found that on the average board you can win a ton by moving from GL_POINTS to a point-sprite. GL points and lines are simply inefficient on the average consumer system." (c) somebody on experts-exchange forum.

I ask it, because in my snow modulation I use simple points for farthest snowflakes, and I didn't try to move it on point sprites. So I didn't test points->point_sprites migration myself, and if somebody did it, would be great to hear his advice.

Thank you again.

charliejay
06-01-2006, 01:26 AM
Just from my reading on this and other message boards, it's my understanding that consumer graphics cards *generally* don't hardware accelerate lines, and perhaps points as well.

To what degree they don't accelerate them I don't know, and it might vary by card and manufacturer anyway...

That's what the remark about inefficiency is about, I think.

About point sprites I know very little, but I'll point out the posibility that the graphics card might treat them as quads internally, thus putting you on a hardware optimized path...