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S3TC Support For Mesa Brought Up Again

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  • #16
    Originally posted by Remco View Post
    Can't AMD, NVIDIA and Intel just come up with an unpatented method of compressing textures? It's not like we're playing the backwards compatibility game, with updates like DX10, DX11, OpenGL 3 and OpenGL 4.
    Yes they could. But I suspect that R&D for this would cost more than buying S3TC licences. So no.

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    • #17
      Originally posted by Remco View Post
      Can't AMD, NVIDIA and Intel just come up with an unpatented method of compressing textures? It's not like we're playing the backwards compatibility game, with updates like DX10, DX11, OpenGL 3 and OpenGL 4.
      There has actually been proposed an alternative, but apparently it was inferior to S3TC and wasn't adopted by anyone: http://en.wikipedia.org/wiki/FXT1

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      • #18
        Alright, seems I was mistaken. I only connected it to Unreal Tournament since it had the explicit option of using S3TC textures if you had a Savage GPU (which could be bypassed). I never saw that option in other games but I guess they must have shortened it to "use compressed textures"...

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        • #19
          Originally posted by NeoBrain View Post
          There has actually been proposed an alternative, but apparently it was inferior to S3TC and wasn't adopted by anyone: http://en.wikipedia.org/wiki/FXT1
          DirectX 11 and OpenGL 4 add two new compression formats that are superior to DXTn and can also be used with HDR images.

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          • #20
            The reason GPUs still have S3TC onboard is because DXTC, a mandatory part of Direct3D since DirectX 6, is the exact same as S3TC's 1, 3, and 5 formats. (2 and 4 are premultiplied-alpha formats, not terribly useful. They're also omitted from the GL extension.) GPU makers license this stuff from Microsoft as part of their DirectX support; you won't be able to do anything about that.

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            • #21
              Now that r300g has progressed to the point where S3TC compression support is the last obstacle in making a lot of games work, I wonder if the work Corbin Simpson did at http://cgit.freedesktop.org/~csimpso...tc-by-the-book may be useful to alleviate the problem of needing an external library (which makes less complete the out-of-the-box experience, which is one main selling point of OS drivers).

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              • #22
                Originally posted by kbios View Post
                Now that r300g has progressed to the point where S3TC compression support is the last obstacle in making a lot of games work, I wonder if the work Corbin Simpson did at http://cgit.freedesktop.org/~csimpso...tc-by-the-book may be useful to alleviate the problem of needing an external library (which makes less complete the out-of-the-box experience, which is one main selling point of OS drivers).
                I'd have to get Ian to take another look. Last time, we did discover one big hole in that branch: D3D permits compressed texture updates with non-compressed data. That could probably be fixed in Gallium but not Mesa.

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                • #23
                  Originally posted by MostAwesomeDude View Post
                  I'd have to get Ian to take another look. Last time, we did discover one big hole in that branch: D3D permits compressed texture updates with non-compressed data. That could probably be fixed in Gallium but not Mesa.
                  Thanks for your answer. If/when it works, would it make libtxc-dxtn completely unnecessary? It is unmantained and IIRC doesn't work with multiple textures.

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                  • #24
                    Originally posted by kbios View Post
                    Thanks for your answer. If/when it works, would it make libtxc-dxtn completely unnecessary? It is unmantained and IIRC doesn't work with multiple textures.
                    It would make it less necessary, certainly. It is maintained, but S3TC, by specification, doesn't necessarily work with multitexturing, and it's broken on many chipsets.

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                    • #25
                      Originally posted by MostAwesomeDude View Post
                      It would make it less necessary, certainly. It is maintained, but S3TC, by specification, doesn't necessarily work with multitexturing, and it's broken on many chipsets.
                      Sorry, I was not clear (I'm under exams, you know, and a bit tired ). With "it is unmantained" I meant libtxc-dxtn, because at http://homepage.hispeed.ch/rscheideg...3tc_index.html
                      it is written that "Note: this page is no longer updated and the code no longer maintained."

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                      • #26
                        BTW, I just realized you are Corbin Simpson. Are you also the same MostAwesomeDude who always frags me in BZFlag?

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