[osg-users] Modern GLSL and OSG

[Jan Ciger]

Hello,

On Sat, Sep 26, 2015 at 5:02 AM, Garth D
<garthy_gso at entropicsoftware.com> wrote:
>
> My original motivation was to move to using "modern" OpenGL (ie. avoiding
> anything deprecated) because I didn't want to be in the situation where I
> started relying on something that was likely to be removed in the future.

Well, I don't think you need to worry about that too much. Yes, the
"old school" OpenGL is marked as deprecated and removed from the Core
profiles (and OpenGL ES 2.0 doesn't support it at all). However, at
least Nvidia (AMD/Ati probably as well) has declared that they are
going to support the legacy profiles for indefinite future.

The reason is that the code is already in the driver and costs them
essentially nothing (the old APIs don't change) and also the ton of
old code that uses it. That's also why the OpenGL 3 was felt to be
such a letdown and not a radical departure in a new direction - there
are simply too many CAD and visualization companies with decades old
codebases that would stop working overnight with a new driver and
there is no business willpower to rewrite that because it works well
enough. Moreover, I am pretty sure that even today you will find major
CAD systems doing atrocities such as using direct mode (glBegin/glEnd)
somewhere in their code ...

> Additionally, I have a need that I know is not going to be handled very well
> in the fixed-function pipeline. From experience I know that whilst the FFP
> is neat for simpler tasks, it feels like a massive burden as the needs get
> more complex.
>
> A last goal was as a learning exercise. The aim was to rely on shader
> functionality a bit more strictly than minimally necessary, as a means of
> taking care of the glaring (and increasingly hard-to-explain professionally)
> hole in my 3D knowledge.

By all means, that is a good reason. Also if you decide to develop on
mobile, you won't have much choice there.

Regards,

Jan