[oe] [meta-browser][PATCH v2 3/4] chromium: Add use-egl PACKAGECONFIG option

[Carlos Rafael Giani]

On 2014-04-29 20:30, Otavio Salvador wrote:
> On Tue, Apr 29, 2014 at 3:39 AM, Carlos Rafael Giani
> <dv at pseudoterminal.org> wrote:
>> By default, Chromium will try to use GLX and regular OpenGL. On embedded
>> platforms, these are often not present, or unaccelerated, and using EGL
>> and OpenGL ES instead makes more sense. To produce builds that use EGL and
>> OpenGL ES by default instead, this PACKAGECONFIG option can be used.
>>
>> An EGL/OpenGLES-enabled build produces a chromium version that renders
>> 2D and WebGL with GPU acceleration (if present).
>>
>> Signed-off-by: Carlos Rafael Giani <dv at pseudoterminal.org>
>> ---
>>   recipes-browser/chromium/chromium_35.0.1883.0.bb | 8 +++++++-
>>   1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/recipes-browser/chromium/chromium_35.0.1883.0.bb b/recipes-browser/chromium/chromium_35.0.1883.0.bb
>> index 1923b4e..1fb050f 100644
>> --- a/recipes-browser/chromium/chromium_35.0.1883.0.bb
>> +++ b/recipes-browser/chromium/chromium_35.0.1883.0.bb
>> @@ -23,6 +23,10 @@ COMPATIBLE_MACHINE_armv7a = "(.*)"
>>
>>   inherit gettext
>>
>> +# this makes sure the dependencies for the EGL mode are present; otherwise, the configure scripts
>> +# automatically and silently fall back to GLX
>> +PACKAGECONFIG[use-egl] = ",,virtual/egl virtual/libgles2"
> There is any way to 'force' build to use egl here and fail if
> something here is missing?
>

That is actually tough. Chromium does not simply link to the EGL and 
GLESv2 libraries; it opens them with dlopen() and gets the GL function 
pointers with dlsym() , as part of the sandboxing strategy. Furthermore, 
cairo requires virtual/egl too (not virtual/libgles2 though). As for 
compilation errors, I haven't found a way to provoke them. I am not 
entirely sure if Chromium is using system EGL/GLES headers, or if it is 
always using its internal copy of the Khronos headers instead. I got 
conflicting responses. So, to be sure (and also to emphasize the 
dependency in the recipe), I added it.

What is certain is that without the --use-gl=egl switch, Chromium will 
always use GLX.