Anyone know why I do not get any speed improvement when I use GL_ELEMENT_ARRAY_BUFFER_ARB?
I make some tests:
I draw 260000 vertices (GL_POINTS)
vertices in system memory -> 63 fps
vertices in video memory -> 380 fps
(speed improvement because I dont tranfert 3 Mb (260000 * 3 float) via the bus every frame)
vertices in system memory -> 58 fps
vertices in video memory -> 160 fps
(slower than glDrawArrays because I tranefrt 1 Mb (260000 vertices) via the bus every frame)
indices in system memory -> 160 fps
indices in video memory -> 156 fps
(so I use VBO extension to store indices in video memory. But I do not get speed improvement).
Therically, I think that the last method should be equal in term of performance to glDrawArrays with vertices in video mem, but it is not the case.
I really dont understand why? and what is the goal of GL_ELEMENT_ARRAY_BUFFER_ARB in this case???
PS: My graphic card is a GeForce 6800 GT