December 1st, 1998, 12:13 PM
Permedia 3 Question Answered
To whom it may concern at 3Dlabs,
I am a very happy Permedia 2 owner (via a Dell Precision workstation 610, congrats on the Dell deal by the way) who is very curious about the Permedia 3. At the risk of bothering you while you are working hard to produce this product, I read an interview of Jean Salvati and had a question. In the interview, both texture caching and texture stage pipelining were discussed. The texture caching looks fabulous but I was unsure of what was being said about the texture stage pipelining. It was said that the Permedia 3 would be able to handle 8 texture stage operations in a single pass/cycle in D3D 6. Does this mean 6 textures, a bump map, and a light map or some combination of 8 of these functions? Generally I see information on the Permedia 3 as supporting only dual texturing in a single pass or two textures and a bump map. Is it really going to be possible to complete 8 operations!?
-- In terms of texture reads, the maximum that P3 can do in a single pass is 1 texture + 1 bump + 1 light map or 1 texture + 1 bump map + 1 gloss map. However, P3 can perform in a single pass/single cycle some texture blending operations, which must be expressed using several DX6 texture stage operations.
Also, does the ability to perform x operations in D3D 6 generally imply that x operations can be accomplished in OpenGL.
--Yes and no. In principle, P3's texture blending hardware is compatible with OpenGL as well as DX6. However, at this time, the multi-texturing interface in OpenGL does not fully take advantage of P3's capabilities. It is possible that, in the future, we will write an extension that will allow developers to fully exploit P3's capabilities in hardware.
I realize this probably isn't true of all operations and that it is driver dependent.
--It's not just driver dependent. In the case of OpenGL, the limitation is the API itself.
As a computer science major that is about to take a first course in computer 3D graphics, I'm very curious about these types of technology. I hope to be able to try some of my course work on my computer this spring rather than on just the SGI's and I look forward to getting a Permedia 3. Thank you very much for your time.
--Good luck with your studies. OpenGL is very easy to learn, and there are many good books about this API. In addition, what you learn on an SGI machine can be easily ported to Windows. Direct3D 6 is much easier to learn than the previous versions, if you have the SDK. If you write a nice multi-texturing or bump mapping demo, let us know.
P.S. the interview was at
December 1st, 1998, 12:15 PM
Sorry about the long post, but it's refreshing to see a company so willing to discuss the technology they are developing and interested in their customers.
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