Bug#793111: OpenGL ES2 support does not work with OpenGL support enabled

[Manuel A. Fernandez Montecelo]

Control: tags -1 + moreinfo


2015-07-21 12:22 Prof. Dr. Gundolf Kiefer:
>Package: libsdl2 (source package)
>Version: 2.0.2+dfsg1-6
>
>It appears that in the present version (2.0.2) of libSDL2,
>hardware acceleration based on OpenGL ES2 does not to work properly if
>both OpenGL and OpenGL ES2 support are compiled in at the same time.
>
>I am using libSDL2 on an embedded Linux board (Cubietruck, A20 SoC,
>Mali 400 GPU), running under Debian Jessie, architecture 'armhf'.
>
>With the stock Debian package, the renderer 'opengles2' is available,
>i.e. reported by 'SDL_GetNumRenderDrivers'/'SDL_GetRenderDriverInfo',
>but not functional on my system. When selected manually, 'SDL_CreateRenderer'
>fails with the SDL error "GLX is not supported".

How do you select it manually, in code or with environment variables?

Also, do you have any implementation of the relevant package installed,
like "libgles2-mesa:armhf" (there are specific packages for some cards)?

Maybe the problem is that the support is there, but when it wants to
load the library to do the actual rendering it doesn't, and emits that
error (or tries that first and defaults to GLX and also fails -- not
sure).


>If I rebuild the package with the only additional configuration option
>'--disable-video-opengl', it works fine.
>
>diff -p libsdl2-2.0.2+dfsg1/debian/rules libsdl2-2.0.2+dfsg1-gk1/debian/rules
>*** libsdl2-2.0.2+dfsg1/debian/rules	Thu Nov 27 18:53:32 2014
>--- libsdl2-2.0.2+dfsg1-gk1/debian/rules	Fri Jul  3 17:11:37 2015
>*************** confflags = --disable-rpath --enable-sdl
>*** 9,14 ****
>--- 9,15 ----
>              --disable-nas --disable-esd --disable-arts \
>              --disable-alsa-shared --disable-pulseaudio-shared \
>              --disable-x11-shared --disable-video-directfb \
>+             --disable-video-opengl \
>              --enable-video-opengles \
>              --enable-video-wayland --disable-wayland-shared
>
>
>I am not too familiar with the libSDL2 code, and I am not sure if this
>issue can easily be solved upstream. For the time being, I suggest to provide
>two alternative binary packages with EITHER OpenGL or OpenGL ES2
>enabled and the other disabled.

SDL libraries had that in the past with audio drivers, and actually it
is quite a hassle.

If the driver GLX does not work in armhf, maybe it's better to disable
it altogether.


Cheers.
-- 
Manuel A. Fernandez Montecelo <manuel.montezelo at gmail.com>