[vlc-devel] [PATCH 6/7] egl_display: improve support detection
Romain Vimont
rom1v at videolabs.io
Wed Mar 3 18:03:18 UTC 2021
On Wed, Mar 03, 2021 at 07:46:47PM +0200, Rémi Denis-Courmont wrote:
> Le keskiviikkona 3. maaliskuuta 2021, 19.36.39 EET Romain Vimont a écrit :
> > A module egl_display must only provide EGL displays where eglTerminate()
> > can be called, even if other modules are using EGL (typically because it
> > is internally refcounted).
> >
> > This is always the case on Android, so egl_display was initially only
> > enabled on Android:
> > https://android.googlesource.com/platform/frameworks/native/+/master/opengl/
> > libs/EGL/egl_display.cpp
> >
> > But this may also be the case on other platforms which support
> > EGL_KHR_display_reference:
> > https://www.khronos.org/registry/EGL/extensions/KHR/EGL_KHR_display_referenc
> > e.txt
> >
> > Co-authored-by: Alexandre Janniaux <ajanni at videolabs.io>
> > ---
> > modules/video_output/opengl/Makefile.am | 2 +-
> > .../video_output/opengl/egl_display_generic.c | 36 +++++++++++++++++++
> > 2 files changed, 37 insertions(+), 1 deletion(-)
> >
> > diff --git a/modules/video_output/opengl/Makefile.am
> > b/modules/video_output/opengl/Makefile.am index 3bee347ef0..c7cbdedfb6
> > 100644
> > --- a/modules/video_output/opengl/Makefile.am
> > +++ b/modules/video_output/opengl/Makefile.am
> > @@ -92,7 +92,7 @@ endif # HAVE_GL
> > libegl_display_generic_plugin_la_SOURCES =
> > video_output/opengl/egl_display_generic.c
> > libegl_display_generic_plugin_la_CPPFLAGS = $(AM_CPPFLAGS) $(EGL_FLAGS)
> > libegl_display_generic_plugin_la_LIBADD = $(EGL_LIBS)
> > -if HAVE_ANDROID
> > +if HAVE_EGL
> > vout_LTLIBRARIES += libegl_display_generic_plugin.la
> > endif
> >
> > diff --git a/modules/video_output/opengl/egl_display_generic.c
> > b/modules/video_output/opengl/egl_display_generic.c index
> > dfa68125c4..cca13beec8 100644
> > --- a/modules/video_output/opengl/egl_display_generic.c
> > +++ b/modules/video_output/opengl/egl_display_generic.c
> > @@ -31,11 +31,47 @@
> >
> > #include "egl_display.h"
> >
> > +static EGLenum GetPlatform(const char *extensions)
> > +{
> > +#ifdef EGL_KHR_platform_x11
> > + if (vlc_gl_StrHasToken(extensions, "EGL_EXT_platform_x11"))
> > + return EGL_PLATFORM_X11_KHR;
> > +#endif
> > +
> > +#ifdef EGL_KHR_platform_wayland
> > + if (vlc_gl_StrHasToken(extensions, "EGL_EXT_platform_wayland"))
> > + return EGL_PLATFORM_WAYLAND_KHR;
> > +#endif
> > +
> > + return 0;
> > +}
> > +
> > static vlc_egl_display_open_fn Open;
> > static int
> > Open(struct vlc_egl_display *display)
> > {
> > +#ifdef __ANDROID__
> > + /* The default display is refcounted on Android */
> > display->display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
> > +#elif defined(EGL_KHR_display_reference)
> > + const char *extensions = eglQueryString(EGL_NO_DISPLAY,
> > EGL_EXTENSIONS); +
> > + if (!vlc_gl_StrHasToken(extensions, "EGL_KHR_display_reference"))
> > + return VLC_EGENERIC;
> > +
> > + EGLenum platform = GetPlatform(extensions);
> > + if (!platform)
> > + return VLC_EGENERIC;
>
> It's nonobvious why you care about the platform here.
> At least it needs an in-line comment IMO.
Because the call to eglGetPlatformDisplay() below expects a platform as
first parameter.
And it is necessary to call eglGetPlatformDisplay() to be able to pass
attributes (to request tracking references).
> > +
> > + const EGLAttrib attribs[] = {
> > + EGL_TRACK_REFERENCES_KHR, EGL_TRUE,
> > + EGL_NONE,
> > + };
> > +
> > + display->display =
> > + eglGetPlatformDisplay(platform, EGL_DEFAULT_DISPLAY, attribs);
>
> Won't this fail badly with EGL < 1.5 ?
In theory, yes. However, the CI is happy:
https://code.videolan.org/rom1v/vlc/-/pipelines/74458
Do we want to support EGL < 1.5? If so, I'll change that.
Regards
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