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bondi

performance difference between VA and CVA

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Hi, I''ve a question about vertex array and compiled vertex array. My machine: AMD Athlon 850 Mhz and GEforce2MX. I draw an object that contains 2,5k triangles and is textured, with glDrawArrays(...); and notice the frame rate. Later I use the extension GL_EXT_compiled_vertex_array and redraw the same object. and notice no difference in the frame rate. [using: LockArraysEXT(...); glDrawArrays(...), UnLockArraysEXT();] My question: Is there a performance difference between VA and CVA?

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I''ve also read the GF performance FAQ on NVIDIA site. And use the
specifed format. I don''t know why there is any performance difference between VA and CVA on my program.

Should if I use glDrawElements instead of glDrawArray(), if I use
CVA?

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Guest Anonymous Poster
Try drawing the mesh two times with VA and then same with CVA

If the draw calls for CVA are placed between Lock and Unlock calls, you should notice a difference.

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quote:
Original post by bondi
My question:
Is there a performance difference between VA and CVA?



no tnl Voodoo3 CVA support, 350 mhz, 13 k detailed triangles per frame

GL_TRIANGLES

without CVA normal VA
30-35 fps

with CVA
60-80 fps


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i believe VAR needs glDrawElements(..)
cva is useful when u share a lot of vertices in a model (eg multipass or a cube)
btw when u are testing for this make your window small eg 200x100 so youre not fillrate bound

http://uk.geocities.com/sloppyturds/gotterdammerung.html

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Where can I find tutorials on using CVA''s? The extension spec I looked at was from 1996 ( which said it was unfinished! ), so can anyone point me somewhere?

Cheers

Death of one is a tragedy, death of a million is just a statistic.

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