libspng VS cgltf

libspng is already in LibHunt. I'm surprised there is no comparison with libpng.

If you want to go all the way, https://learnopengl.com/ is a favorite around here. You could build a glTF viewer from scratch starting from that tutorial and https://github.com/jkuhlmann/cgltf and eventually building towards https://google.github.io/filament/Filament.html or whatever wacky artsy direction you like.

Use https://github.com/jkuhlmann/cgltf to parse the files. https://github.com/ocornut/imgui for your UI. Maybe https://www.libsdl.org/ just to set up a window, handle mouse clicks and initialize the GL context in that window.

Use glTF and https://github.com/jkuhlmann/cgltf Or, looks like you are using C#, so https://github.com/vpenades/SharpGLTF

Do you really have to use fbx? An open format like gltf is better supported, and there are bazillions loaders(I use cgltf without any issues, which is also used by raylib, Unigine and bgfx). It's also a perfect fit for OpenGL.

I recently discovered this pattern in cgltf (https://github.com/jkuhlmann/cgltf), and I agree, it makes deployment so much nicer.

Use https://github.com/jkuhlmann/cgltf It’s the most popular loader.

It's easy to generate a BVH for a generated triangle set (like a fractal pyramid or a dense cube). But, quickly generating a high quality BVH for a loaded model requires some research. Use https://github.com/jkuhlmann/cgltf to load models.

Write a simple glTF viewer in OpenGL. This is a throw-away warm-up. So, don't fret over the code. Don't do anything complicated. Shoot for a simple, forward renderer for a simple, animated character with trivial Phong lighting, diffuse map, normal map and a basic directional shadow map. Use OpenGL ES 3.0/GL 4.3 API with no crazy features. Don't worry about performance. Use https://github.com/jkuhlmann/cgltf to load the files. KTX is a great container for textures.