Re: [Algorithms] VIPM With T&L

[Dave E. <eb...@ma...>]

From: "Sam Kuhn" <sa...@ip...>
> a) I've read that its possible to throw the vertices of a model at the 3d
> card (So T&L is possible)
> And just maintain the indexed lists into that vertex array using collapses
> and merges.

The source code for my game engine book has an implementation
of this (actually, the first update does and is available at my web site
for purchasers of the book).  The vertices and indices are ordered so
that as you collapse edges, you just reduce the maximum index for
the vertex array and for the connectivity index array.

> Doesn't that mean you have to make the card (hardware) transform all of
the
> vertices in the highest resolution representation of the model each frame?
> even though the current lod might only need say 100.. or am I missing
> something?

The packed model-space vertices can be cached on the graphics
card.  Each frame you only change the connectivity information and
the model-to-world transforms.  Then let the graphics card do its thing.

> b) Say you wanted 1000 spaceships on screen sharing a single VIPM model,
how
> does this work with (a)?

Yes, both objects share the model-space data that is cached on
the card.  The objects potentially have different LODs and
model-to-world transforms.

--
Dave Eberly
eb...@ma...
http://www.magic-software.com