[Public WebGL] gamma/color profile and sRGB

Florian Bösch [email protected]
Wed Nov 26 05:41:28 PST 2014


OpenGL ES 2.0 doesn't have glBlitFramebuffer (but ES 3.0 has).
glBlitFramebuffer can be substantially slower than a quadpass. It's also
capable of performing interpolation, which suggests that at least some
conversion rules still apply.

The OpenGL ES 3.0 specification states in section 4.3 Reading and Copying
Pixels:

When values are taken from the read buffer, if the value of FRAMEBUFFER_-
> ATTACHMENT_COLOR_ENCODING for the framebuffer attachment corresponding to
> the read buffer is SRGB (see section 6.1.13), the red, green, and blue
> components
> are converted from the non-linear sRGB color space according to equation
> 3.24.


FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING is framebuffer attachment tied. It
can be queried by GetFramebufferAttachmentParameteriv but it can only be
set by attaching an sRGB texture.


On Wed, Nov 26, 2014 at 2:19 PM, Mark Callow <[email protected]> wrote:

>
> On Nov 25, 2014, at 4:58 PM, Florian Bösch <[email protected]> wrote:
>
> 2. Spec out a new context creation attribute for WebGL 2.0 adding
>> support for allocating an sRGB drawing buffer
>>
> Which can fail unless you have support for TEXTURE_SRGB_DECODE so you can
> read out raw values from an sRGB texture for use in a non-linear color
> space compositor.
>
>
> What about glBlitFramebuffer? IIRC correctly that does not do any
> conversions. I don’t have time to check the OpenGL spec. right now. Sorry.
>
> Regards
>
>     -Mark
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://khronos.org/pipermail/public_webgl_khronos.org/attachments/20141126/8631d127/attachment.html>


More information about the public_webgl mailing list