Looking for a working recipe to run osgearth with GL3 support on Linux

[elbarto1980]

Hi,
I am starting this discussion hoping to have a place to share experiences with those of you that (like me) are working on Linux.
I have been using without any problem osgearth 3.2.0 and GL2 for a few years now and recently I have been trying, every now and then, to update my installation to the latest versions of OSG and osgearth, using GL3.

After several attempts, I have decided to sum up my linux recipe in a Docker container that seems, in some extent, to works (unfortunately it has a few limitations).
Since the up-to-date vcpkg package for linux is still a work in progress, my dockerfile starts from scratch, installing packages on an Ubuntu 20.04 base image. The docker file is available in the pull request #2387 that I have opened.

The problem where I am stuck at the moment is related to model rendering: when I add a model, colors are mixed up... in a deterministic way, it seems 😀... that I cannot fully understand 😦.
Here is what happens:

1. In the first (upper-left) image, the model has its own texture, but it has a red overlay that it takes from the color of the label;
2. Then I press the keyboard button 's' that shows statistics. As the "Frame Rate" text appears, the model's overlay color becomes white (upper-right image);
3. I press 's' again (lower-left image), and the overlay color turns to orange, as the GPU text in the statistics box;
4. I press 's' twice again (lower-right image) and the overlay is white, as the text in the "View" box.

In the terminal, it prints the message Warning: Material::apply(State&) - not supported..

Something similar happens when I load a model that has materials, but no texture.

This time, materials are not shown at all. The model only takes the color of the green label at first, and then the one of the statistics text. No warning messages are printed.

I will keep updating the Dockerfile if I have any updates, hoping to hearing from you as well. Consider the dockerfile as a sandbox.

Thank you!

[gwaldron]

The re-coloring is an example of "state leakage" and is typically caused by a model that leaves something undefined (like its colors array most commonly), in which case OSG just uses whatever "leaked" from the previous drawable. I would check that your 3D model has a color array defined.

The warning msg Warning: Material::apply(State&) - not supported comes from OSG, and will print when OSG sees a FFP state attribute (like Material) but can't apply it because FFP support is unavailable. It would be nice if you could suppress this OSG message, but there's no way to do so. The osgEarth ShaderGenerator is supposed to replace osg::Material with appropriate lighting uniforms in that case, but maybe it's not happening for some reason.

[elbarto1980]

Thank you, I will check the 3D model[s] I exported from Blender

[elbarto1980]

Hi, I have been able to fix the "state leakage" for the textured model by adding the options --addMissingColors --fix-transparency-mode MAKE_ALL_STATESET_OPAQUE to osgconv when converting the fbx model exported from Blender to an osgt file.
This solves the color issue but makes OSG print tons of Warning: detected OpenGL error 'invalid enumerant' at after RenderBin::draw(..) messages. They can only be silenced by setting OSGNOTIFYLEVEL=FATAL.

Now I have to address the Material issue for all the models that do not have a texture and I still have two void StateSet::setGlobalDefaults() ShaderPipeline disabled. messages (that should not have consequences) if I do not change the OSGNOTIFYLEVEL env variable.

I'll keep you posted...

[gwaldron]

OK.
So where are things now. If the model displaying correctly, but you just want to get rid of annoying messages?
Or are models with only materials (and no texture) displaying incorrectly?

[elbarto1980]

I think I can live with the annoying messages. At the moment, I am still figuring out how to render models with only materials, but I think I am close (a couple of days tops 🤞).
I will let you know a.s.a.p.
Thank you again!

[elbarto1980]

Here I am with an update.
To render all the model, I have to use two different approaches for textured models and models that have just materials.

Textured models:

• must have everything defined, otherwise you can use the parameters --addMissingColors --fix-transparency-mode MAKE_ALL_STATESET_OPAQUE when converting them using osgconv;
• have to be run through the shader generator, otherwise I get a completely white model.

osgParticles:

• have to be run through the shader generator, otherwise I get big squares and rectangles.

Models with materials (at least the ones I have):

• have not to be run through the shader, neither loaded using the .osgearth_shadergen postfix, or I get the state leakage shown in previous posts.

The state leakage is probably caused by a lacking compatibility of the models I use with the osgearth shaders. I read the Blender 4.0 manuals regarding import-export for Wavefront OBJ and FBX, but tweaking the export settings does not really change the outcome.
I uploaded the osgt model with materials here if anyone is interested in taking a peek under the hood...

[gwaldron]

Would it help if the shadergenerator were to add missing color arrays?

[elbarto1980]

To be honest, I have no clue... 🙄