sphere.obj was made by subdividing a cube, unwrapping it using cube projection, and then using the "To-sphere" tool in Blender to fully smoothen it out.
Make sure you select "shade smooth" before exporting!

Other settings:
    Up axis: Y
    Forward axis: -Z

The winding order in .obj files is always counter-clockwise, so my script (genmesh.py) uses reversed() to reverse this and homogenous the winding order
across meshes