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Re: [Public WebGL] Gamma correction and texImage2D/texSubImage2D



On Tue, Sep 7, 2010 at 20:38, Chris Marrin <cmarrin@apple.com> wrote:
> We have been staunchly against specifying any extensions in the 1.0 spec. I think we should stick with that philosophy.

I completely agree with that. When referring to EXT_texture_sRGB I was
thinking in term of feature rather than about its extension nature.
After all, it has been promoted in core OpenGL since 2.1 - which,
luckily, is the minimum GL version we support on OpenGL desktops as
far as I know.


>And remember, the difference here from OpenGL is that, today ALL images sent to texImage2D are unmodified. (...) We have images coming in from an external system (HTML), so we need to be able to allow that external system to condition the images or not. It's the same as the flip Y and premultiplied alpha flags.

Flip Y and premul are a bit different imho as they are mere helpers
against binary input and binary processing limitations within a
browser/JavaScript context, they do not do conversion per-se.
On the other hand, we already perform conversion to "downsample"
images from the "external system" (usually stored as RGB8888) to more
efficient representation in texture memory (eg. RGB565) through
texImage2D's format arguments. The sRGB to linear color space
conversion is a very similar operation that we can perform at
specification time as well.

Considering the feature has been present in OpenGL for a while and
that it is likely to be introduced in a future revision of ES (iirc
Mark's words?), I do not see a reason to diverge from OpenGL here,
especially when considering the arguments against using a "toggle
parameter" as discussed in the original extension specification.


Regards,

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