View Full Version : Billboarding with vertex program?

12-20-2002, 05:59 AM
I am computing the veritces of a quad in such a way that the quad will always face the camera.
Would it be possible to use a vertex program for this?

As you probably assume I know nothing about vertex programs, so if it is possible, a detailed description would be very appreciated!
Thanks for your time.

12-20-2002, 06:30 AM
www.cgshaders.org (http://www.cgshaders.org)

12-20-2002, 07:30 AM
Hmmm yes, thanks.
So you don't know if it possible?

12-21-2002, 02:23 AM
Of course it's possible, because all you need is your matrix, that's all.

[This message has been edited by M/\dm/\n (edited 12-21-2002).]

12-21-2002, 03:31 AM
Do you suppose it will be faster?
I don't want to be a pest, but my idea was that if I knew that the vertex program-approach would not really increase my fps, than I would focus on different parts of the program rather than learning Cg now without any real use for me (yet).
Thanks for the reply

12-21-2002, 11:16 AM
CG is prety easy for beginning & results are whole lot better. Only minus is that you need T&L card. Not sure about performace yet, although, a lot of work is moved to GPU instead of CPU, so - parallel performance.

12-22-2002, 04:14 AM
It just came to me: Does the GeForce2 support vertex programs at all?

I can't download Cg at the moment anyway, server is strange...

[This message has been edited by B_old (edited 12-22-2002).]

12-22-2002, 10:34 AM
Works on my GF2GTS, I even can run NV30 demos with emu. And current non-beta compiler should support fr programs too.
Yes there is serious problems with server, unfortunately as often http://www.opengl.org/discussion_boards/ubb/frown.gif

Old GLman
12-23-2002, 01:27 AM
You dont need cg for this, just use ARB_vertex_program. GF2 supports it.

Old GLman

12-23-2002, 03:01 AM
Just downloaded CG final. There are some pure OGL demos. CG is easier & have optimizing compiler to make all the stuff faster (I hope so, havn't checked out).

12-24-2002, 05:35 AM
Well thanks for the replys.
I see what I can manage. It seems to be possible as you say.