Jump to content
  • Advertisement
Sign in to follow this  
Daivuk

OpenGL GL_ARB_vertex_buffer_object vs SGI_compiled_vertex_array

This topic is 4121 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hi all, I'm wondering if people can give me the differences between: GL_ARB_vertex_buffer_object (OpenGL 1.5) and SCI_compiled_vertex_array (OpenGL 1.1) In my understanding, they both do the same thing. Which consist of putting the vertices into the VRam for faster rendering.

Share this post


Link to post
Share on other sites
Advertisement
Your understanding is wrong as the CVA extension does nothing of the sort; what it allowed you to do was tell OpenGL that, until it was told otherwise, vertex data in a section of memory wasn't going to change and it could cashe the results of the transform for later passes.

However, this extension has been effectively obsolete since the introduction of hardware T&L with the orignal Geforce cards (so around 2000!) as the caching was only useful when the CPU had to do all the work.

In short; forget the compiled vertex array extensione even exists.

Share this post


Link to post
Share on other sites
Thanks Phantom. Will prevent me doing mistakes.

Last version of GL_ARB_vertex_buffer_object is 2003. Is that means it's for only recent video cards only?

What If the user have a GeForce 2. Is it worth it to compile them into Display lists? In my past projects, DLs occurred to be so damn fast! Why people are not using DLs anymore? What is bad with them? It's directly stored into the VRam. (Right!?)

Share this post


Link to post
Share on other sites
Quote:
Original post by Daivuk
Last version of GL_ARB_vertex_buffer_object is 2003. Is that means it's for only recent video cards only? What If the user have a GeForce 2.

Graphics drivers add back-compatibility to older graphics cards. VBOs are supported on the GeForce2, if a recent driver is installed.

Quote:
Original post by Daivuk
Is it worth it to compile them into Display lists?

No.

Quote:
Original post by Daivuk
In my past projects, DLs occurred to be so damn fast! Why people are not using DLs anymore? What is bad with them?

VBOs are faster, far more flexible and more storage efficient.

Quote:

It's directly stored into the VRam. (Right!?)

So are static VBOs.

Share this post


Link to post
Share on other sites
DLs are stored in VRAM if they are geometry only DLs
If you put PushMatrix and other weird stuff in there, then it's kept in RAM and played back.

There isn't much reason to use DL unless you want to run on really old cards that support GL 1.1

Share this post


Link to post
Share on other sites
Thanks for the info guys. Really helpful.
We want to support old computer. So if extension doesn't exist, we will put the Geom into DLs. :)

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!