3d in WebAssembly

[Pswin]

1. I was wondering when I use web-assembly which 3D API (OpenGL, OpenGL ES, Vulkan) should I use? or it is based on WebGL?

2. are OOpenGLContext and QOpenGLFunctions supported by web-assembly?

3. Am i able to use threads (specially for rendering)?

[lorn.potter]

WebGL is based on opengl es2, WebGL 2 is based on opengl es3. Emsripten (and therefor Qt WebAssembly) has support for both.
Thread support in wasm is still experimental, there are limitations.