DivideTriangle

renderSphere = (quality_level) ->
  # Get basic points
  base = octahedronPoints()
  points = []

  # Generate Subdivided points
  for index = 0 to base.length step 3
    points = concat(
      points,
      divideTriangles(
        base[index],
        base[index+1],
        base[index+1],
        quality_level
      )
    )

  # Render
  glBegin(GL_TRIANGLES)
  for point in points
    glVertex3f(point.x, point.y, point.z)
  glEnd()

divideTriangle = (Vector3f a, Vector3f b, Vector3f c, int level) ->
  Vector3f v0, v1, v2
  if level > 0
    v0 = mid(a, b)
    v1 = mid(b, c)
    v2 = mid(c, a)

    return concat(
      divideTriangle(a, v0, v1, level-1),
      divideTriangle(c, v1, v2, level-1),
      divideTriangle(b, v2, v0, level-1)
    )
  else
    return [
      normalise(a),
      normalise(b),
      normalise(c)
    ]

mid = (Vector3f a, Vector3f b) ->
  new Vector3f((a.x + b.x) / 2, (a.y + b.y) / 2, (a.z + b.z) / 2)