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



Gregg, your summary is totally reasonable.  What is tilting me is what
followed -- proposals to convert incoming sRGB data to linear 8888
RGBA, specify the framebuffer as linear 8888 RGBA, and to a
linear-to-sRGB_Alpha conversion on WebGL's output when compositing
with the web page.

-T

On Mon, Sep 6, 2010 at 7:23 PM, Gregg Tavares (wrk) <gman@google.com> wrote:
> I think I'm missing what everyone is arguing about. As far as I can see it
> there is only 1 issue. Should WebGL **optionally** support color space
> conversion when calling TexImage2D and TexSubImage2D.  That's it.
> WebGL already specifies that if the incoming format is a lossless 8bit
> format (ie, an 8bit png) that the bits in the file must be passed straight
> through, no conversion. There are conformance tests for this. This is to
> support getting non-image data into WebGL.
> The only question that came up should there be an **option** to let the
> browser do color space conversion (and should that conversion be explicit).
> The simplest form of that is "should the browser be allowed to do whatever
> it normally does for img tags".
> Right now the browser is not allowed to change it bits if the source image
> is a lossless 8bit format. If you want it to do it's "normal" color
> conversion thing where normal is unspecified then you first paste your image
> into a canvas then use the canvas as your source for texImage2D. If your
> browser happens to do color space conversion you'd get the converted colors
> using that path since once it's pasted into canvas there's no way to know
> what it was originally or get the original bits.
> So, the question came up, should we have a flag to let the color space
> conversion happen without having to do so by pasting into a canvas.
> In that case the flag could be
> WEBGL_UNPACK_ALLOW_COLORSPACE_CONVERSION_ON_8BIT_LOSSLESS_IMAGES
> which is just a flag to tell the browser it can do whatever it wants
> If you're on a browser that does color space conversions (firefox) your
> images will match what it does for img tags on the page. If your'e on a
> browser that doesn't do color space conversion (safari/chrome) again, your
> images will match what it does for img tags on the page. Note again, this is
> only for 8bit lossless formats. For all other formats it's completely up to
> the browser.
>
>

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