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Re: [Public WebGL] Compressed textures.



As far as I know, ETC1 is IP free and it is supported by a number of ES2 devices.

http://www.khronos.org/registry/gles/extensions/OES/OES_compressed_ETC1_RGB8_texture.txt

The main problem for most current WebGL implementations would be how to support ETC1 on a Desktop GL driver though.  I've heard claims that it can be transcoded to DXT1 though.

Daniel


On 2010-05-30, at 1:39 PM, Chris Marrin wrote:


On May 29, 2010, at 6:30 PM, Steve Baker wrote:

I guess we're more or less limited on texture file types to the set that
_javascript_ generally supports: GIF/PNG/JPG ?  Since GIF and JPG are
totally hopeless as texture formats and PNG's compression isn't
agressive enough because it's not lossy, it would be truly spectacularly
handy if WebGL could also support some kind of compressed format - DDS
would be best.  (Although it's a bit 'microsofty/D3D-ish' - it's
actually a REALLY good  format for textures with tons of support out
there and a 1:1 mapping to the underlying hardware).

Given that we'd like to run on low-end hardware, and even on high end
stuff, the transmission time from the server is not insignificant -
also, we don't want to use _javascript_ to do compression on-the-fly.


There will be no compressed texture formats supported in the first release of WebGL. This is really proprietary formats rearing their ugly head. There currently exists no compressed texture format that is free of legal encumbrances. If we did support an encumbered format which would work untouched on some hardware (and therefore no expose the browser to legal issues) we would have to decompress that texture in software for use in other hardware which did not support it (which would expose the browser to legal issues). So we've decided to avoid the issue in the first release in hopes that there will exist an unencumbered format in the future.

-----
~Chris
cmarrin@apple.com


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                        Daniel Koch -+- daniel@transgaming.com
Senior Graphics Architect -+- TransGaming Inc.  -+- www.transgaming.com