[OE-core] [PATCH 1/2] mesa: use distro_features_check to abort build without opengl feature

[Nicolas Dechesne]

hi,

On Mon, Sep 9, 2013 at 2:40 PM, Nicolas Dechesne
<nicolas.dechesne at linaro.org> wrote:
> On Mon, Sep 9, 2013 at 2:12 PM, Burton, Ross <ross.burton at intel.com> wrote:
>>
>> On 9 September 2013 13:08, Martin Jansa <martin.jansa at gmail.com> wrote:
>> >> +REQUIRED_DISTRO_FEATURES = "opengl"
>> >
>> > Is this really needed? I was building mesa in distro without opengl for
>> > long time and was considering (probably incorrectly) opengl
>> > DISTRO_FEATURE more
>> > like sign of proper hw GL libraries.
>>
>> I'd always understood the "opengl" DISTRO_FEATURE to mean "give me GL
>> support".  *What* that means depends on the target hardware, could be
>> entirely software rendering through Mesa or binary HW drivers.
>
>
> how about gl vs gles?
>
> i have been trying to understand over the last couple of days whether or not
> 'opengl' in DISTRO_FEATURES means OpenGL and OpenGLES. I don't think it's
> clearly indicated anywhere.
>
> in libsdl recipe, we have this:
>
> DEPENDS = "${@base_contains('DISTRO_FEATURES', 'directfb', 'directfb', '',
> d)} \
>            ${@base_contains('DISTRO_FEATURES', 'opengl', 'virtual/libgl',
> '', d)} \
>
> and in EXTRA_OECONF we add this:
> ${@base_contains('DISTRO_FEATURES', 'opengl', '--enable-video-opengl',
> '--disable-video-opengl', d)} \

back on this topic... something is weird. as i said above, we built
our OE based distro for ARM platform with *no* GL support, but with
GLES support. As soon as we pull libav in our images it DEPENS on
virtual/libsdl, and as mentioned above libdsl with 'opengl' in
DISTRO_FEATURES will end up with adding dependency on virtual/libgl
which we don't want (and don't have on our platform).

how do we get around this problem?

i am still not convinced that we should treat GL and GLES with a
single 'DISTRO_FEATURE' since they aren't 'equivalent' features. I
understand we need a mechanism to say if the platforms has 'graphics'
support, and for some recipes 'graphics' is enough, but especially for
libsdl this isn't enough since on GLES platforms we don't want
--enable-video-opengl to be enabled since that is a GL feature, not
GLES.

thanks