[DO NOT MERGE] Support gltf

[0b5vr]

Description

• Add gltf support.
• TBD

Points need review

• I don't really do Rust coding usually! Have no% confidence about my code this time
  • no confidence about resource management and stuff of course
  • module / file management is a part that is most mystery for me
• Geometry / GeometryAttribute are having vbo / vao as a member. I'm not sure this is a good design decision...
• We probably have to consider a lot of things about yaml and shader interface
  • yaml interface. Currently, there is a field called gltf that can be specified directly to vs / vs+fs type stages and I don't think this is a good decision
  • geometry attributes. position attribute is passed to shader as location=0 for now. we have several options about this part:
    • naming each attributes as like in vec3 position
    • define macros like #define ATTR_INDEX_POSITION 0 for forward compatibility
  • material informations. we are going to have a lot of uniforms related to materials
    • I have defined material_alpha_cutoff and material_base_color for now
    • Textures are not supported yet and I assume it's a spicy part considering resource management funnies
    • plus we also need macros like ALPHA_MODE_MASK (naming is also an issue)
  • matrices. I'm currently sending model_matrix based on world space model matrix comes with gltf node graph
    • We might want to have camera in near future?

...I realized this PR involves a lot of major design decisions 😩
You can take it a single sample of project exploration and just discard the PR 😅 ,
I already have enjoyed my rare opportunity reading and writing Rust code

[0b5vr]

wait, I was not meant to make a PR on slerpyyy/ instead of 0b5vr/

😩

[0b5vr]

this leaves me an INVALID_OPERATION error on exit.

[0b5vr]

It's weird that it sometimes fails to get uniform location of textures......

sh4der-jockey/src/util/mesh.rs

Line 26 in c64b388

let location = unsafe { gl::GetUniformLocation(program_id, *name) };

[sp4ghet]

Anything from gl_debug_check! immediately after & before? could be an error elsewhere that breaks OpenGL state if your name is guaranteed to be sound