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Fooberman

Wireframe mode

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Hey guys, I guess i have two questions, about performance. I noticed that when i render a heightmap in wireframe mode (glPolygonMode(GL_LINE)) there is a huge slowdown. Why is this so? Also, Something funny, i just upgraded from an old GeForceDDR to a GeForce4 MX and it seems that immediate mode rendering seems quite a bit slower. Most of the drawing in my code uses vertex arrays and either glDrawElements() or glDrawArrays(), but i have a couple that use just calls to glVertex3f() and the like, and they slow down the rendering by maybe 10 fps, way more than they did on my older card. Does this make any sense to anyone? Chris ~

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Ya, I get a huge slowdown too using glPolygonMode( GL_FRONT_AND_BACK, GL_LINE ): from 139 to 15 fps (and 30 fps with GL_POINT) . I''d like to know why, as well. ..... The lines get textured, so I figure that, in a way, its even more work since there are 4 lines per polygon (not counting shared lines..)

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i read in another thread somewhere that each line is actually a tri-strip... dunno how valid that is, and i cant search for the thread to see what came of that discussion..
it''s certainly explain your slowdown though.

one thing you might do to speed things up is to make sure you disable GL_LINE_SMOOTH and GL_POINT_SMOOTH.
these are costly anti-aliasing calculations.. i lose 30fps in my
game with them enabled :\

-eldee
;another space monkey;
[ Forced Evolution Studios ]


::evolve::

Do NOT let Dr. Mario touch your genitals. He is not a real doctor!

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In the older geforces, lines were rendered twice in line mode (as far as i know).

I also heard that the lines are approximated by triangles..

just my 2c

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