Aw: Re: Help needed to update our use of OpenGL

[Markus Mützel]

> Gesendet: Mittwoch, 12. September 2018 um 19:00 Uhr
> Von: "John W. Eaton" <address@hidden>
> An: mmuetzel <address@hidden>, address@hidden
> Betreff: Re: Help needed to update our use of OpenGL
>
> On 09/12/2018 11:21 AM, mmuetzel wrote:
> > What needs to be changed with the way lighting is handled?
> > I am by no means an expert in OpenGL. But I don't remember using deprecated
> > functions when I added the light graphic object.
> > If you could point to the problematic functions or constructs, I might be
> > able to have a look at it.
> > 
> > If someone else wants to help or prefer to do that, I won't mind either. ;-)
> 
> To begin, see this page:
> 
>    https://www.khronos.org/opengl/wiki/Legacy_OpenGL
> 
> also this page specifically about lighting notes that the fixed-pipeline 
> glMaterial and glLight functions are part of the legacy APIs:
> 
>    https://www.khronos.org/opengl/wiki/How_lighting_works

IIRC, that is the page I used as a reference to implement lighting.  Looks like
I completely ignored or forgot about the deprecation warning at the top of the
page... :-/

As a side note: GLSL was first introduced with OpenGL 2.0.  The default OpenGL
version that is supported by Windows (without drivers) is OpenGL 1.1 (software
rendering).  Most graphic hardware should be able to support OpenGL 2.0 now
(released 2004).  But users need to install the appropriate drivers for their
graphics hardware to run software that requires OpenGL 2.0.  That might not be
necessary for Octave since we ship an OpenGL software renderer with the Windows
installer.
I don't know how the Qt software fallback would behave with this in mind.

I hope we won't need to support both OpenGL "dialects"...

Markus