kilograham
Posts: 76
Joined: Fri Apr 12, 2019 11:00 am
Location: austin tx

GLX vs EGL

Sat Jul 27, 2019 3:23 am

We have (at least with FKMS and mesa) GLX and EGL ... to the extent that we may be able to choose between them is there a preference, or a performance difference for the areas they overlap - is GLX built on top of EGL internally for Pi?

jdonald
Posts: 417
Joined: Fri Nov 03, 2017 4:36 pm

Re: GLX vs EGL

Sun Jul 28, 2019 9:11 pm

kilograham wrote:
Sat Jul 27, 2019 3:23 am
a performance difference for the areas they overlap
anholt once said on these forums:
> [Regarding GLX vs EGL] you get a bunch of bandwidth overhead due to regrettable choices in the GLX spec which EGL fixed.

He says something similar in this article from pre-Broadcom days.
is GLX built on top of EGL internally for Pi?
Running ldd libGLX.so shows no linker dependency on libEGL, and from a cursory glance of the code at git://anongit.freedesktop.org/mesa/mesa they appear to have independent implementations.

kilograham
Posts: 76
Joined: Fri Apr 12, 2019 11:00 am
Location: austin tx

Re: GLX vs EGL

Mon Jul 29, 2019 3:31 pm

Cool, thanks; i'm looking at an existing codebase that uses GLX on X11, but EGL for wayland... debating whether there would be performance benefits in moving the X11 code to use EGL

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