Re: MXE and GL_MULTISAMPLE

[Rik]

On 05/24/2014 09:00 AM, address@hidden wrote:
> Date: Sat, 24 May 2014 06:17:33 -0700 (PDT)
> From: PhilipNienhuis <address@hidden>
> To: address@hidden
> Subject: [MXE] build errors (GL_MULTISAMPLE etc not found)
> Message-ID: <address@hidden>
> Content-Type: text/plain; charset=us-ascii
>
> Hi,
>
> While trying to a cross-build a recent octave-4.1.0+ I get compile errors
> (relating to core Octave cs be8d7721ac16 "Use OpenGL line smoothing when
> multisample is not found"):
>
> : 
> ..../gl-render.cc:647:17: error: 'GL_MULTISAMPLE' was not declared in this
> scope  
>       glEnable (GL_MULTISAMPLE);
> :
> ..../gl-render.cc:649:22: error: 'GL_SAMPLE_BUFFERS' was not declared in
> this scope
>        glGetIntegerv (GL_SAMPLE_BUFFERS, &iMultiSample);
> :
> .../gl-render.cc:650:22: error: 'GL_SAMPLES' was not declared in this scope
>        glGetIntegerv (GL_SAMPLES, &iNumSamples);
> :
>
> A few minute before, that same octave-4.1.0+ was built fine for (and runs
> fine in) linux, all I did after that was "make all dist", copy that into
> mxe-octave, fix the checksums, and start an mxe build.
>
> Comparing my system's  /usr/include/GL/gl.h  with  mxe's 
> <mxe-octave>/usr/usr/i686-w64-mingw32/include/GL/gl.h  I can confirm that
> definitions for GL_MULTISAMPLE etc are lacking in the latter. 
>
> (A little surprising to me as my linux build system (Mageia-2) is a bit old,
> the octave build dependencies are the distro-supplied ones and I figured in
> MXE the various build tools & dependencies would be more up-to-date.)
>
> OK, my mxe build tree isn't bleeding edge (~5 weeks old,  578:583d3bf548e6
> "texinfo: update to 5.2 and install all tools"). But in later changesets I
> didn't spot opengl-related updates.
Philip,

According to this Stack Overflow question
(http://stackoverflow.com/questions/4207506/where-is-gl-multisample-defined) 
Windows
does not include GL_MULTISAMPLE in gl.h.  Apparently this doesn't mean it
might not have the capability.  Before this capability was incorporated in
to mainline code at OpenGL 1.3 it was an extension.  As a quick test, you
might try "#include glext.h" and change GL_MULTISAMPLE to
GL_MULTISAMPLE_ARB.  If that works I guess we could figure out a way to
code that into a test for configure.ac.  I checked my MXE sources and
glext.h includes the alternate definition.

--Rik