Create a sphere geometry dynamically like glutSolidSphere(). (Ref: http://wgld.org/d/webgl/w025.html, http://marina.sys.wakayama-u.ac.jp/~tokoi/?date=20090912, http://stackoverflow.com/q/7687148)

create_sphere.py

import numpy as np

def create_sphere(radius, slices, stacks):
    """Create a sphere geometry dynamically like glutSolidSphere().

    :param radius: Radius of sphere.
    :param slices: A number of slices of longitude.
    :param stacks: A number of stacks of latitude.
    """
    radius = float(radius)
    if type(slices) is not int or type(stacks) is not int:
        raise TypeError("The type of `slices` or `stacks` isn't int.")
    pos, nor, tex = ([], [], [])
    for i in range(stacks+1):
        tex_y = float(i) / stacks
        r = math.pi * tex_y
        ry = math.cos(r)
        rr = math.sin(r)
        for j in range(slices+1):
            tex_x = float(j) / slices
            tr = math.pi * 2 * tex_x
            tx = rr * radius * math.cos(tr)
            ty = ry * radius
            tz = rr * radius * math.sin(tr)
            rx = rr * math.cos(tr)
            rz = rr * math.sin(tr)
            pos.append([tx, ty, tz])
            nor.append([rx, ry, rz])
            tex.append([1-tex_x, tex_y])
    idx = []
    for i in range(stacks):
        for j in range(slices):
            r = (slices + 1) * i + j
            idx.extend([r, r+1, r+slices+2])
            idx.extend([r, r+slices+2, r+slices+1])
    return np.float32(pos), np.float32(nor), np.float32(tex), np.int16(idx)