""" Samples a point from the surface or from the interior of solid sphere which is split in two parts. """
from typing import Union, Optional, List
import numpy as np
from mathutils import Vector
from blenderproc.python.sampler.Sphere import sphere
[docs]
def part_sphere(center: Union[Vector, np.ndarray, List[float]], radius: float, mode: str,
dist_above_center: float = 0.0,
part_sphere_dir_vector: Optional[Union[Vector, np.ndarray, List[float]]] = None) -> np.ndarray:
""" Samples a point from the surface or from the interior of solid sphere which is split in two parts.
https://math.stackexchange.com/a/87238
https://math.stackexchange.com/a/1585996
Example 1: Sample a point from the surface of the sphere that is split by a plane with displacement of 0.5
above center and a normal of [1, 0, 0].
.. code-block:: python
PartSphere.sample(
center=[0, 0, 0],
part_sphere_vector=[1, 0, 0],
mode="SURFACE",
distance_above_center=0.5
)
:param center: Location of the center of the sphere.
:param radius: The radius of the sphere.
:param mode: Mode of sampling. Determines the geometrical structure used for sampling. Available: SURFACE (sampling
from the 2-sphere), INTERIOR (sampling from the 3-ball).
:param dist_above_center: The distance above the center, which should be used. Default: 0.0 (half of the sphere).
:param part_sphere_dir_vector: The direction in which the sphere should be split, the end point of the vector,
will be in the middle of the sphere pointing towards the middle of the
resulting surface. Default: [0, 0, 1].
:return: A random point lying inside or on the surface of a solid sphere.
"""
if part_sphere_dir_vector is None:
part_sphere_dir_vector = np.array([0, 0, 1], np.float32)
else:
part_sphere_dir_vector = np.array(part_sphere_dir_vector).astype(np.float32)
part_sphere_dir_vector /= np.linalg.norm(part_sphere_dir_vector)
if dist_above_center >= radius:
raise ValueError("The dist_above_center value is bigger or as big as the radius!")
while True:
location = sphere(center, radius, mode)
# project the location onto the part_sphere_dir_vector and get the length
loc_in_sphere = location - np.array(center)
length = loc_in_sphere.dot(part_sphere_dir_vector)
if length > dist_above_center:
return location