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Re: [whatwg] Adding features needed for WebGL to ImageBitmap

From: Peter Kasting <pkasting@google.com>
Date: Wed, 10 Jul 2013 17:13:07 -0700
Message-ID: <CAAHOzFD4UcX_BrGr-W_p5UwOCJmowjEZz3=Nuqq+nshOXxN=ag@mail.gmail.com>
To: Ian Hickson <ian@hixie.ch>
Cc: WHATWG <whatwg@whatwg.org>, Kenneth Russell <kbr@google.com>, Rik Cabanier <cabanier@gmail.com>, "Tab Atkins Jr." <jackalmage@gmail.com>
On Wed, Jul 10, 2013 at 5:07 PM, Ian Hickson <ian@hixie.ch> wrote:

> (The other two options don't make much sense to me even for GL. If you
> don't want a color space, don't set one. If you don't want an alpha
> channel, don't set one. You control the image, after all.)


I only have a small amount of graphics experience, but I don't think that
latter comment is right, at least.

At least for the alpha channel, as Gregg already wrote, a lot of GL
algorithms use that data for something per-pixel that's not "alpha"
(generally some other kind of per-pixel map).  It's not appropriate for the
browser to assume that it's safe to muck with the values there.  Fixing
this by instead trying to pass these values separate from the rest of the
pixel data is inefficient as well as just weird from the perspective of
anyone with significant experience in using these sorts of algorithms.

PK
Received on Thursday, 11 July 2013 00:13:31 UTC

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