Backface culling in OpenGL
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I have a quick question. I know doing backface culling in OpenGL is very easy. But how do you do it for triangle_strips, because in a tri_strip triangles alternate windings. If you have to constantly change GL_CCW to GL_CW and back again it would seem like the function overhead would outweigh (maybe not) the benefit of backface culling. Does backface culling really increase performance by a significant factor?
I don''t know about OpenGL but in D3D every second triangle in a triangle strip is "turned around" by D3D so backface culling still works properly. It kinda makes sense and I could imagine that such a feature was implemented in OpenGL, too.
- JQ, PWC Software
"There are no pessimists, optimists and realists; just pessimists and optimists who think they're realists" -me
- JQ, PWC Software
"There are no pessimists, optimists and realists; just pessimists and optimists who think they're realists" -me
urm, no, with triangle strips, the winding shouldnt change.
The strip sorta goes like this:
up
down
(move up and left)
down
(move up and left)
down etc.
Or the other way rounf for opposite winding.
basically, what Jonny Quest said was correct. Try a simple strip.
You'll see that it'll display, without the need to change the
winding.
Have fun, and good luck.
Edited by - Ferrit on October 20, 2000 4:42:58 PM
The strip sorta goes like this:
up
down
(move up and left)
down
(move up and left)
down etc.
Or the other way rounf for opposite winding.
basically, what Jonny Quest said was correct. Try a simple strip.
You'll see that it'll display, without the need to change the
winding.
Have fun, and good luck.
Edited by - Ferrit on October 20, 2000 4:42:58 PM
Yeah, I just couldn''t put it into words properly. Damn.
- JQ, PWC Software
"There are no pessimists, optimists and realists; just pessimists and optimists who think they're realists" -me
- JQ, PWC Software
"There are no pessimists, optimists and realists; just pessimists and optimists who think they're realists" -me
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