Inconsistent OpenGL support across architectures

[Gregor Jasny]

Hello,

today I noticed build failures of v4l-utils on arm64 hosts:
https://launchpadlibrarian.net/406083796/buildlog_ubuntu-bionic-arm64.v4l-utils_1.17.1-201901131615~ubuntu18.04.1_BUILDING.txt.gz

This is due to the OpenGLES2 feature is enabled on arm64 (but this feature is not enabled for amd64):

> /usr/include/x86_64-linux-gnu/qt5/QtGui# grep -i opengl qtgui-config.h
> #define QT_FEATURE_opengles2 -1
> #define QT_FEATURE_opengl 1
> #define QT_FEATURE_opengles3 -1
> #define QT_FEATURE_opengles31 -1

vs:

> /usr/include/aarch64-linux-gnu/qt5/QtGui$ grep -i opengl qtgui-config.h
> #define QT_FEATURE_opengles2 1
> #define QT_OPENGL_ES true
> #define QT_OPENGL_ES_2 true
> #define QT_FEATURE_opengl 1
> #define QT_FEATURE_opengles3 1
> #define QT_OPENGL_ES_3 true
> #define QT_FEATURE_opengles31 1
> #define QT_OPENGL_ES_3_1 true

Is the inconsistent feature setting intentional? The Debian Qt packages seem to select Desktop OpenGL across architectures.

Thanks,
Gregor

[Gregor Jasny (gjasny)]

I guess this is due to the following lines in debian/rules:

gles2_architectures := armel armhf arm64
ifeq ($(DEB_HOST_ARCH),$(findstring $(DEB_HOST_ARCH), $(gles2_architectures)))
 extra_configure_opts += -opengl es2
else
 extra_configure_opts += -opengl desktop
endif

Still my question is why those architectures (should) differ from the regular ones. And why Ubuntu is behaving differently than Debian.

In my case I need access to qopenglext.h contents which does not get loaded if OpenGL ES2 support is present.

[Dmitry Shachnev (mitya57)]

Sorry for the delay, for some reason I have not received a mail about this bug.

Starting with Ubuntu 19.04 release, there is no difference between Debian and Ubuntu: both use OpenGL ES on armel/armhf, and desktop OpenGL on the other architectures. Initially I wanted to add arm64 to that list too, but after the discussion in https://lists.debian.org/debian-devel/2018/11/msg00457.html the plan was changed.

The reason for using OpenGL ES on armel/armhf is that the majority of devices with that architecture are mobile devices that have video chips supporting only OpenGL ES natively.

It looks like v4l-utils currently builds fine on all supported Ubuntu releases, but if you have problems with supporting OpenGL ES versions, please let me know.