PDA

View Full Version : Programmable Vertices



Gamewave
12-06-2003, 02:54 AM
Hello,

Any one tried ARB vertex_program and discovered that it performs more than 50% slower than fixed TnL pipeline, or faster by 3 frames per second than it is software counterpart?

I found ths on my GeForce 2 MX 400
Dirver 1.4.1

Thanks.

sebh
12-06-2003, 03:37 AM
Officially, ARB_VERTEX_PROGRAM are not on the geForce2(Mx,GTS).

I don't know how you can parform arb_vertex_program on geForce2 mx?!?!?

Ysaneya
12-06-2003, 04:22 AM
The extension is present but only supported in software on pre-Geforce 3 and the Geforce 4 mx.

Y.

sebh
12-06-2003, 06:04 AM
Thanks, i didn't know this.

If it's software, it's normal that it's slow.

Gamewave
12-07-2003, 11:58 PM
Thanks for the information.
But how in the hell Direct3D vertex shading works as it's implemented in HW. This means that my card has a special unit for vertex instructions, and I believe it's the same VPU used for OpenGL, isn't it?
Then what is reason for implementing OpenGL VPs in software?

Ysaneya
12-08-2003, 12:03 AM
It's also done on software in D3D. From what i remember, there is a "mixed vertex processing" mode, which allows hardware T&L, but to switch to software vertex shading if the hardware doesn't support it. There's no miracles.

Y.