[Mesa-dev] [RFC] New EGL extension: EGL_EXT_platform_display

[Pekka Paalanen]

On Tue, 26 Feb 2013 12:53:49 -0800
Chad Versace <chad.versace at linux.intel.com> wrote:

> On 02/25/2013 11:58 PM, Pekka Paalanen wrote:
> > On Mon, 25 Feb 2013 09:09:22 -0800
> > Chad Versace <chad.versace at linux.intel.com> wrote:
> 
> > Thank you for the reply. Indeed, that dance to check for the extension
> > is non-trivial, and I think it might be good to explain somehow in the
> > spec, maybe in the Q&A section?
> 
> Yes, I'll add the topic to the Issues section.
> 
> > I quickly checked the EGL 1.4 spec, and could not spot any mention of
> > whether eglGetProcAddress needs a valid context or display or anything.
> > Does it require any initialization? Well, should not matter much I
> > guess, since in any case you have to open a display first to get the
> > extensions string.
> > 
> > Btw. what is EGL_DEFAULT_DISPLAY in Mesa, what does it give us?
> 
> Ah, that is complicated. In the Mesa configuration that nearly everyone
> uses, eglGetDisplay(EGL_DEFAULT_DISPLAY) calls XOpenDisplay(NULL) to acquire
> the display. If Mesa is configured as Wayland-centric, though,
> then eglGetDisplay(EGL_DEFAULT_DISPLAY) calls wayland_display_connect(NULL)
> to acquire the display. It's also possible to select to which platform
> EGL_DEFAULT_DISPLAY belongs with the env var EGL_PLATFORM, but, according
> to Kristian, that method is deprecated.

Indeed, I think setting EGL_PLATFORM will override the whole display
type detection, even if you did pass a specific display object instead
of EGL_DEFAULT_DISPLAY.


Thanks,
pq