[osg-users] Modern GLSL and OSG

[Garth D]

Hi Jan,

On 25/09/15 05:18, Jan Ciger wrote:> -----BEGIN PGP SIGNED MESSAGE-----
 > On 24/09/15 00:19, Garth D wrote:
 >> Many thanks for the interesting suggestion. :)
 >>
 >> My main development environment is Linux-based, with a secondary
 >> virtualised Windows development environment. Due to the
 >> visualization (VirtualBox) I don't believe I can do much in the way
 >> of development with ANGLE due to its DX backend, at least with my
 >> current setup.
 >
 > Um, wouldn't it be far easier to simply ask OSG to create an OpenGL
 > 3.x/4.x core context instead? Then you don't have the legacy stuff
 > available and don't need to bother with hacks like Angle.

Thankyou for the suggestion. :)

I have to admit being unsure how to set the specific context at present.

 From what I've read, there'd need to be a glXCreateContextAttribsARB 
call somewhere to create the GL3 context under Linux- and there doesn't 
seem to be one. Skimming the source (I'm presently using OSG 3.2.1, but 
had a peek at 3.4.0) suggests that perhaps this support is only 
available on a Windows build. On the cmake side, OSG_GL3_AVAILABLE in my 
build is off. However, glVersion=4.4 appears in my log during a build.

However, I am probably fine even if I am not grasping things entirely at 
this point. It is something I can experiment with later on, probably on 
my existing Windows build environment. Whether I experiment with ANGLE 
from there or not is something I can weigh up from that point. Thanks 
for the additional input.

I also just noticed that my prior email used "visualization" rather than 
"virtualisation". Whoops. ;} I think I need to place a little less faith 
in spellcheck suggestions.

I'm beginning to suspect that aiming for strict OpenGL 3+ or 4+ might 
not be the best thing for me to concentrate at the moment. I might be 
better off just using it where it helps and leaving a jump to "pure" 
modern GL until a later date.

Cheers,
Garth