[mythtv] #13351: Add OpenGL ES configurability/autodetection

[Peter Bennett]

On 11/25/18 2:37 PM, Piotr Oniszczuk wrote:
> Hi,
>
> Working on ARM HW (AmLogic s905, RPI) I need OpenGL ES support in myth.
>
> I added OpenGL ES configurability and it works in following way: there is new configure switch: —enable-opengles
>
> Overall logic: OpenGL ES is disabled by default (if no switch passed to configure or —disable-opengles passed to configure)
> If —enable-opengles is passed to configure, configure will detect all required and set conditional USING_OPENGLES if all is OK.
> If anything is missing - configure will exit with error.
>
> So summarising:
>
> A) ./configure WITHOUT —enable-opengles
>
> Result:
> OpenGL ES disabled; what OS provides doesn’t matter
> USING_OPENGLES is not set
>
> B) ./configure WITH —enable-opengles
>
> B.1) System has proper support for OpenGL ES. This means:
> a) pkg-config present to EGL and GLESv2
> b) *.h, GLESv2 libs are present
> c) Qt provides Open GL ES
>
> Result:
> configure sets USING_OPENGLES
>
> B.2) System has broken support for OpenGL ES
> (any of a) or b) or c) from B.1 are not valid)
>
> Result:
> configure exits with error
>
> Why exit with error?
> If user asks for OpenGL ES but system is not properly prepared to build, user should be explicitly notified by this issue.
>
>
> This way current build bots should still work ok.
> Only change is required for android building: now it requires adding —enable-opengles to configure params
>
> I tested it on x86 and RPI3 with fully working OpenGL ES.
>
> Let me know what You think
>
>    
>    
>
What is the problem with the current setup? OpenGL ES is already used in 
android and raspberry pi, and as far as I know it is already enabled if 
the correct libraries are present.

Peter