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View Full Version : vertexarray -> is drawelements faster than drawarray ?



HamsterofDeath
03-02-2003, 07:09 AM
is it faster ?
or is it not ?

JustHanging
03-04-2003, 03:46 AM
Hi,

I'd guess it depends on your geometry. With drawArrays you don't get to take advantage of shared vertice, so if you have lots of them, it's propably slower. If you don't have any, I could imagine drawArrays to be a bit faster. Better just test it with your own data.

-Ilkka

Roderic (Ingenu)
03-04-2003, 04:04 AM
It would probably be faster, and if not, equally fast.
Simply said, the drivers/hardware can manage its cache easily with the index array.

jwatte
03-04-2003, 10:59 AM
If there is no vertex sharing, then the overhead of sending indices will just slow things down.

If you want any kind of vertex sharing and vertex cache usage, then DrawRangeElements is the way to go.

Daher
03-04-2003, 12:15 PM
hmmn... how hard is it exactly to code a simple test program? ... too hard as I can see... :P

just a thought

HamsterofDeath
03-04-2003, 11:53 PM
how does the vertex sharing thing work ?
does opengl calculate every vertex once, and then draws them ?
if yes, i would get a good speedup...
or do i have to sort the points ?