This bug report was migrated from our old Bugzilla tracker.

These attachments are available in the static archive:

• reproduction case (testsrgb.c, text/plain, 2015-04-06 01:14:42 +0000, 310 bytes)

Reported in version: HG 2.1
Reported for operating system, platform: Linux, x86_64

Comments on the original bug report:

On 2015-03-02 10:06:30 +0000, wrote:

I'm using Ubuntu Gnome 14.10, with Nvidia 550 TI and proprietary drivers.

Whenever I request SDL_GL_SetAttribute(SDL_GL_FRAMEBUFFER_SRGB_CAPABLE, 1), I get "Can't find matching GLX visual" message on trying to create the window.

Thing is, that I DO get an sRGB capable OpenGL framebuffer on the machine, even if I don't explicitly request it.

I've also tested it on Windows and got an sRGB framebuffer there regardless of the state of SDL_GL_FRAMEBUFFER_SRGB_CAPABLE flag.

This bug impairs creation of cross-platform projects that require sRGB for proper display of color.

On 2015-03-04 06:09:12 +0000, Ryan C. Gordon wrote:

I remember hearing something about this. We'll look at this for 2.0.4.

--ryan.

On 2015-04-06 01:14:42 +0000, Ryan C. Gordon wrote:

Created attachment 2106
reproduction case

This program fails to make a GL context on X11 with Nvidia's proprietary drivers (prints "(nil)") It works on Intel's open source drivers, at least on this machine (prints a valid pointer address for the GL context).

--ryan.

On 2015-04-06 03:42:25 +0000, Ryan C. Gordon wrote:

Hmm, the Nvidia drivers don't like when you choose a visual with:

attribs[i++] = GLX_FRAMEBUFFER_SRGB_CAPABLE_ARB;

...it instead wants...

attribs[i++] = GLX_FRAMEBUFFER_SRGB_CAPABLE_ARB;
attribs[i++] = True;

(which appears to be incorrect, according to the GLX specification.)

Mesa seems to allow this, though, so I guess we'll just force that True item for now.

--ryan.

On 2015-04-06 04:08:04 +0000, Ryan C. Gordon wrote:

(In reply to Ryan C. Gordon from comment # 3)

Hmm, the Nvidia drivers don't like when you choose a visual with:

attribs[i++] = GLX_FRAMEBUFFER_SRGB_CAPABLE_ARB;

...it instead wants...

attribs[i++] = GLX_FRAMEBUFFER_SRGB_CAPABLE_ARB;
attribs[i++] = True;

(which appears to be incorrect, according to the GLX specification.)

Uh, wait, Mesa wants the same thing, maybe it was just more forgiving about picking a visual, or some other cosmic force stepped in.

http://cgit.freedesktop.org/mesa/mesa/tree/src/glx/glxext.c?id=5e59f895c468c1ac497ad925b8bddd7f227c89a2#n548

It's not clear to me where it says this attribute needs a "True" specified; other boolean items in the Mesa implementation don't do this (look for FETCH_OR_SET).

I'm confused. But at least the fix is easy now!

--ryan.

On 2015-04-06 04:15:51 +0000, Ryan C. Gordon wrote:

Oh well, this should be fixed now in http://hg.libsdl.org/SDL/rev/f5b468964b0b

--ryan.