10.3 `SphereGeom` -- Sphere geometry

class SphereGeom( radius=1.0, segmentsu=16, segmentsv=8): radius is the radius in the local coordinate system.
segmentsu and segmentsv are used when the sphere has to be tesselated (either for interactive display or when converted to a triangle mesh).

A SphereGeom has the following slots:

Slot	Type	Access	Description
`cog_slot`	vec3	r	The local center of gravity
`inertiatensor_slot`	mat3	r	The local inertia tensor
`radius_slot`	float	rw	The radius
`segmentsu_slot`	int	rw	The number of segments in u direction
`segmentsv_slot`	int	rw	The number of segments in v direction

cog: Center of gravity with respect to the local coordinate system.

inertiatensor: Inertia tensor with respect to the local coordinate system.

radius: The radius of the sphere.

segmentsu: The number of segments in u direction.

segmentsv: The number of segments in v direction.