ETC2 Texture Compression Looks Good For OpenGL

[elanthis]

It will not make S3TC obsolete for existing games, though it might make it obsolete for future titles several years from now. But by the time those new titles come out the S3TC patent will be close to expire anyway, so it will not really make a difference.

s/several years/5-10 years/

Hardware has to be released supporting this. No hardware yet released that does so, and it'll be a year or three before they do, mostly likely. Then you need to wait until a vast majority of the target demographic has said hardware. GPUs tend to have a lifetime of around 5 years for gamers; the 8800gt still has some users according to the Steam Hardware survey, and that came out in 2006 (6 years ago).

There's a reason almost nobody uses OpenGL 4 and that D3D11 is only just finally starting to be used in major games (and generally with downlevel feature sets either supported or used exclusively). The specs that come out today aren't usable by developers until after full support for those specs has saturated the market.

[Setlec]

oh yeah, that's right the issue was about the patent's validity...

thanks Ansla.

[Ansla]

It expires in 2017 if I remember correctly, the discussion was whether it was ever valid at all.

[Setlec]

wasn't the patent supposed to be already expired?

[Ansla]

It will not make S3TC obsolete for existing games, though it might make it obsolete for future titles several years from now. But by the time those new titles come out the S3TC patent will be close to expire anyway, so it will not really make a difference.

[Kayden]

Is ETC2 really required by GL 4.3 as stated in the article? I don't see it listed here: http://cgit.freedesktop.org/mesa/mesa/tree/docs/GL3.txt

Yes, it is. For varying degrees of proof, see: wikipedia, Khronos press release, and most importantly, the spec (whole entire section devoted to ETC2).

[Ansla]

I believe it's not listed separately because it's covered by ARB_ES3_compatibility.

PS: is there a similar list for ES3?

[oibaf]

Is ETC2 really required by GL 4.3 as stated in the article? I don't see it listed here: http://cgit.freedesktop.org/mesa/mesa/tree/docs/GL3.txt

[russofris]

None of our currently shipping hardware has native support for ETC2, which means we have to implement it in software. That means that textures are uploaded and stored to the GPU in an uncompressed format, which isn't terribly efficient, but there's not much else we can do. That will at least make applications using ETC2 compressed textures work. (I believe Chad's volunteered to write the software decoder, unless someone beats him to it.)

Kayden,

Is ETC2 arithmetically similar enough to a supported texture-compression format that you might be able to do partial acceleration via an intermediate format? Basically, take a loss on the CPU which would transcode ETC2 to the intermediate, and make up, or exceed the loss on the GPU?

The example that comes to mind is when we were able to get an old SigmaDesign hardware MPEG1 decoder to partially accelerate MPEG2 video.

F

[Setlec]

None of our currently shipping hardware has native support for ETC2, which means we have to implement it in software. That means that textures are uploaded and stored to the GPU in an uncompressed format, which isn't terribly efficient, but there's not much else we can do. That will at least make applications using ETC2 compressed textures work. (I believe Chad's volunteered to write the software decoder, unless someone beats him to it.)

Thank you for the quick answer. you guys are impressing me!