RE: [Algorithms] How to pack a vertex
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RE: [Algorithms] How to pack a vertex
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From: Ville M. <wi...@hy...> - 2002-02-15 15:52:26
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> compatible and edgebreaker can get down to 1 bit per vertex. Edgebreaker is mainly a compression algorithm for connectivity, not vertex positions. The original implementation was able to compress the connectivity to an 1-2 bits per triangle. Compression of vertex positions was only briefly discussed, and an average storage requirement of 12 bits per vertex was achieved. That's still an order of magnitude more than 1 bit/vertex. cheers, -wili -- o Ville Miettinen, Lead Programmer o Hybrid Graphics, Ltd. o Email: wi...@hy... o Web: www.hybrid.fi -----Original Message----- From: gda...@li... [mailto:gda...@li...]On Behalf Of Dean Calver Sent: Friday, February 15, 2002 14:54 To: gda...@li... Subject: RE: [Algorithms] How to pack a vertex Convert vertices into an optimal space first (find a optimal bounding box and transform vertices into that). Then quantise to an appropriate amount (will depend on your app). That's as about the limit of vertex shader compatible. But if not in a vertex shader, use edge adjacency to predict which vertex is next and delta encode the difference then use a standard binary compressor (LZW etc) on the resulting data. Some key words to search on Eigen-space : for getting the vertex data into a minimal set with no lose in quality (except for float issues) Edgebreaker : for the current state of art in prediction compression You can get about 1/2 or 1/4 of the original size for vertex shader compatible and edgebreaker can get down to 1 bit per vertex. Bye, Deano Dean Calver, Creature Labs. P.S. I wrote a chapter on the vertex shader part in the ShaderX book. Its not out yet, check out http://www.shaderx.com for release info etc. -----Original Message----- From: Pierre Terdiman [mailto:p.t...@wa...] Sent: 15 February 2002 12:23 To: gda...@li... Subject: Re: [Algorithms] How to pack a vertex By delta-encoding the error vector between that vertex position and a predicted vertex position? ...which takes into account the nearby vertices and the mesh connectivity. Else simply quantize them relatively to a bounding box ? But one way or another I think you need to use nearby vertices and some "global knowledge" (opposed to "local") to reach the best compression ratios. Lots of papers out there (Rossignac, wavelet stuff, etc) Best way depends on what you're really trying to do. ----- Original Message ----- From: Erwin de Vries <er...@vo...> To: <gda...@li...> Sent: Friday, February 15, 2002 12:34 PM Subject: [Algorithms] How to pack a vertex > Hi, > > I was wondering what you guys consider the best way to pack a vertex while > preserving as much precision as possible. No assumptions could be made about > its magnitude. Its not a normal. > > SYL Erwin > > > _______________________________________________ > GDAlgorithms-list mailing list > GDA...@li... > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list > Archives: > http://sourceforge.net/mailarchive/forum.php?forum_id=6188 _______________________________________________ GDAlgorithms-list mailing list GDA...@li... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=6188 _______________________________________________ GDAlgorithms-list mailing list GDA...@li... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=6188 |
