30-bit displaying with Krita?

Adrian Page adrian at pagenet.plus.com
Tue Dec 29 14:01:27 CET 2009

On 29 Dec 2009, at 12:14PM, Boudewijn Rempt wrote:

> On Tuesday 29 December 2009, LukasT.dev at gmail.com wrote:
>> On Tuesday 29 December 2009 09:06:20 Boudewijn Rempt wrote:
>>> On Friday 25 December 2009, Adrian Page wrote:
>>>> It will also be necessary to request a 10-bit visual when the OpenGL
>>>> context is created. Without that, there's likely no benefit in storing
>>>> the data in greater than 8 bits as it will just get converted to 8-bit
>>>> when written to the frame buffer, unless the card opts to dither (my
>>>> Nvidia card doesn't).
>>> Is that actually doable with QGlWidget? I've tried to find something in
>>> the Qt docs, but I cannot figure it out.
>> Creating OpenGL rendering context with Qt is described here
>> http://www.opengl.org/discussion_boards/ubbthreads.php?ubb=showflat&Number=
>> 262519 _______________________________________________
> That doesn't look too good...

I'm not sure why those examples are doing things at that low a level. Qt has a QGLFormat class that you can use to set the context format before it's created. That class includes options to set the red/green/blue channel sizes, which is what we'd want to change. See http://doc.trolltech.com/4.6/qglformat.html#setDefaultFormat. 

Note that only graphics cards supporting 30-bit mode will allow you to create a 30-bit context, so this will be difficult to test.


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