[osg-users] EXTERNAL: Re: EXTERNAL: Re: EXTERNAL: Re: Where is CreateContextAttribs() being used?

Chris Hanson xenon at alphapixel.com
Thu Apr 11 11:43:32 PDT 2019

On Thu, Apr 11, 2019 at 5:46 PM Rowley, Marlin R <marlin.r.rowley at lmco.com>

> Sebastian,
> I have written the shaders for GL 3.3 so that’s done.  When RenderDoc
> runs, I’m assuming it’s only checking that window context.  I am NOT
> assuming that it can comb through my code and determine that I’ve used a
> fixed-function GL call somewhere and therefore spits out the message.

  Well, it's not just the GLSL version, you need to create a context that
either can or can not handle non-core  FFP functions. So, outside of your
shaders, even other pieces of OSG code could be requiring non-core
features. You'd need to build OSG and osgEarth with the proper build
options to completely remove their utilization of any non-core abilities,
and then make sure you (or OSG) create a core-only Context.

> In general, I’d like to have a working GPU debugger.  Right now, we are
> struggling to find out values of local variables in the shaders that aren’t
> uniform.  We would also love to be able to pinpoint bottlenecks in the code
> from the GPU side to optimize performance.

Debugging shader local variables in-situ is a pretty weak point of GLSL.

My recommendation is to try to create a toy program that replicates the
critical part of your code, as debugging there will be a lot easier, and
then you can apply the fix to your larger environment. Working within OSG
and osgEarth can be very daunting when things aren't working the way you

> ----------------------------------------
> Marlin Rowley
> Software Engineer, Staff
> [image: cid:image002.jpg at 01D39374.DEC5A2E0]
> *Missiles and Fire Control*
> 972-603-1931 (office)
> 214-926-0622 (mobile)
> marlin.r.rowley at lmco.com
Chris 'Xenon' Hanson, omo sanza lettere. Xenon at AlphaPixel.com
Training • Consulting • Contracting
3D • Scene Graphs (Open Scene Graph/OSG) • OpenGL 2 • OpenGL 3 • OpenGL 4 •
GLSL • OpenGL ES 1 • OpenGL ES 2 • OpenCL
Legal/IP • Forensics • Imaging • UAVs • GIS • GPS •
osgEarth • Terrain • Telemetry • Cryptography • LIDAR • Embedded • Mobile •
iPhone/iPad/iOS • Android
@alphapixel <https://twitter.com/alphapixel> facebook.com/alphapixel (775)
623-PIXL [7495]
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openscenegraph.org/pipermail/osg-users-openscenegraph.org/attachments/20190411/51cf25af/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 3114 bytes
Desc: not available
URL: <http://lists.openscenegraph.org/pipermail/osg-users-openscenegraph.org/attachments/20190411/51cf25af/attachment.jpg>

More information about the osg-users mailing list