Re: mxe-octave status

[John W. Eaton]

On 10/20/2017 06:00 PM, John W. Eaton wrote:
> On 10/20/2017 04:28 PM, Philip Nienhuis wrote:
>
> > Ah, I see I misunderstood; you mean that mesa version provokes a 
> > segfault.
> > (Sorry for not following the whole issue in detail - which relates to 
> > not having hit the issue with older system opengl32.dll libs yet.)
>
> No, the mesa version works fine for me.  It's when I've built the qt5 
> version with mesa and then I attempt to use the system opengl32.dll 
> instead.  As far as I know, this should work since the API should be the 
> same.  It's supposed to be a "drop-in replacement"

It looks like the problem that I've experienced is due to the system 
opengl implementation that I have with a Windows 7 installation inside 
virtualbox.  When I tried the same Octave installer on a Windows 10 
system running on real hardware with Intel graphics, it worked fine with 
the system opengl and the mesa version.

This is the info I get from __opengl_info__ on the virtual box system 
(using Octave 4.2.1):

  version    = 1.1.0
  vendor     = Microsoft Corporation
  renderer   = GDI Generic
  extensions =
    GL_WIN_swap_hint
    GL_EXT_bgra
    GL_EXT_paletted_texture

so maybe this is insufficient for the qt5 QOpenGLWidget?  Or there is 
just a bug that could be fixed.  Either way, it appears that with the 
mesa opengl32.dll we now have a way to too avoid these problems.

I don't know that we need to detect and repair the problem 
automatically, but we should probably at least have a configuration 
option that arranges for Octave to use the mesa opengl library to do 
software rendering.

jwe