Skip to main content
gamedev.net
🔒 Locked

Index Buffer Question

Started by Cybertron 2 replies 300+ views
Original Post
Cybertron
Cybertron
I have a question with index buffers. You give it a set of vertecies and indicies but what if half of the vertecies are not used? This is used for a terrain LOD by not drawing half the vertecies (like Geomipmaps). Will this hurt performace, or does rendering take way more time then transforming And about static/dynamic IBs, which would be better for generating the indecies: - One large static/dynamic IB that is rewritten occasionally - Re-create a static VB occasionally Because it is only re-written occasionally is it ok to use a static VB?
Namethatnobodyelsetook
Namethatnobodyelsetook
On many card, all vertices in the range of firstvertex to firstvertex+numvertices will be transformed. On other cards, it''s not a big deal as they''ll just transform whatever the index buffer says needs transforming next. If possible, put the vertices that are only used in higher levels of detail after the vertices used in low level of detail.

Yes, in general, rendering takes much more time than transforming, unless you have lots of very small polys. Your LOD system should help ensure you have a decent poly count to screen size ratio.

I''d use a dynamic IB. It''s okay to occasionally lock a static IB if you think it''s okay to occasionally stall your game.
Cybertron
Cybertron
Thanks alot! I will see how it works out

Topic Locked

This topic has been locked by a moderator. New replies are not allowed.

Sign in to reply to this topic.