RE: [Algorithms] Directx8 (its christmas)

[Charles B. <cb...@cb...>]

I gave a little look to the D3D PM stuff.  In general, it looks
quite good.  The big pluses are :

1. it's there, free, and quite fast
2. seems to work with skinned meshes
3. seems to work well with multiple textures
    (though I have a nagging feeling that performance with multiple
    textures may not be so hot, eg. lots of extra memory use, based on
    how Hoppe has described handling per-face properties in the past).

The minuses are :

1. you don't have the code, and the MS docs are very lean on explanation
   of what's actually going on.
2. seems to refuse to collapse some meshes for no apparent reason.  If you
   just import a bunch of meshes, most of the work, but occasionally you'll
   get one that doesn't collapse at all (too many verts?) and sometimes you'll
   get one that only collapses a few hundred faces and then refuse to do more.
   Weird.  Maybe the debug runtimes would spit an explanation.
3. no way to get the error information out.  eg. it doesn't tell you what the
   geometric error is from collapsing 100 faces.  This means you have to get
   your artists to manually rate the quality of the collapses so that you can
   set up your distance <-> triangle count relationship.

Anyway, it's better than any object LOD system that's ever shipped in a game,
and hopefully it will raise the bar in general; no one should ever ship a
game again with worse CLOD than d3dxpm.

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Charles Bloom           www.cbloom.com