OSG and VSG interoperability

[trinhtuanlong]

I am currently developing an application using OSG Earth, and I want to render the OSG scene to a texture and share this texture with VSG using GL_EXT_memory_object and VK_KHR_external_memory. Is it feasible? Is there a better way to do the same thing? How do I implement this?

[robertosfield]

The extensions exist but you'll need to look up how well they are support by the Hardware/OS/Driver combinations that you want you application to run on. The osg2vsg has some very old experimental code that might useful to look at.

You may be better of just using Rocky, PelicanMappings VSG native version of osgEarth.

[robertosfield]

What do you mean?

File extensions? 3rd party libraries that I didn't write?

If you want us to help guide you then you'll need to provide some context on what you are tying to achieve, please remember that we don't have a window into your brain, you have to tell us what's rattling around in there.

[trinhtuanlong]

What I mean is OpenGL extensions, like GL_EXT_memory_object. Normally I would have to load the function pointer into my opengl app or use GLEW and just the function there. But I don't know how to call these function using OSG. If I want to call glImportMemoryFdEXT for example, how do I call this in an OSG app? Do I just call it? Do I have to include the glew header as well? Do I call these function in a RealizeOperation when I create the graphic context?

[robertosfield]

Have a look at osg2vsg for it's extension setup.

Also, do you really need osgEarth? Are you sure there aren't native VSG alternatives that would work for you?

[trinhtuanlong]

Thank you.
I have looked into using rocky, but the app is currently unstable on linux. My app is a thermal radiation simulation app, which works on GIS data. I must render a whole city using maps from GIS systems. I need an api that handles coordinate transform and geoTIFF files. The thermal radiation simulation can be handled using OSG Earth alone, but I also have to simulate the sensor response and optical systems, which involves a lot of GPGPU. Maybe I will review Rocky again.

[robertosfield]

I haven't tested Rocky recently so can't advice on the how easy it would be to resolve the instability issue. In general Vulkan/VSG/C++17 are pretty consistent across platforms, better than OpenGL.