How to avoid this Xvfb error: ES2 Prism: Error - GLX extension is not supported

[Antoine Martin]

On 12/12/16 19:51, Long Vu wrote:
> On Mon, Dec 12, 2016 at 1:06 PM, Long Vu <long.vu at intelerad.com> wrote:
>> On Mon, Dec 12, 2016 at 12:20 PM, Adam Jackson <ajax at nwnk.net> wrote:
>>> On Mon, 2016-12-12 at 12:13 -0500, Long Vu wrote:
>>>
>>>> Would it be this xvfb-run option ?
>>>>
>>>> -s ARGS   --server-args=ARGS        arguments (other than server number and
>>>>                                     "-nolisten tcp") to pass to the Xvfb server
>>>>                                     (default: "-screen 0 640x480x8")
>>>>
>>>> I am not familiar with X server options, what server args I would need
>>>> to get rid of this "ES2 Prism: Error - GLX extension is not supported"
>>>> error?
>>>
>>> Yes, I think it would be:
>>>
>>> xvfb-run -s "-screen 0 640x480x24" # ... whatever else you use
>>
>> I tried xvfb-run -s "-screen 0 640x480x24", still the same error.  Any
>> other clues?
>>
>> ES2 Prism: Error - GLX extension is not supported
>>     GLX version 1.3 or higher is required
>> Xlib:  extension "RANDR" missing on display ":99".
>>
>>
>> Now that I run at 24 bpp, maybe I should force GLX to be enabled?  Or
>> have to specify a GLX version, otherwise the default is less than 1.3?
>>
> 
> I bumped the resolution and manually try to enable GLX, still the same error.
> 
> xvfb-run -s '-screen 0 1024x768x24 +extension GLX +iglx' <command>
> 
> I don't know what else to try.
Your Xvfb on CentOS will not support the GL extension.
If you really must use OpenGL with your client applications:
1) Use Xdummy
https://xpra.org/trac/wiki/Xdummy
2) Use VirtualGL
http://www.virtualgl.org/

Cheers
Antoine