import itertools
import numpy as np
from .internal import Shape, ShapeDecorator, ShapeAttribute
[docs]@ShapeDecorator
class Spheropolygons(Shape):
"""A collection of rounded polygons.
A `Spheropolygons` object has a common shape and rounding radius
for the whole collection. Each shape can have a different
orientation and color. Vertices should be specified in
counterclockwise order.
"""
_ATTRIBUTES = list(itertools.starmap(ShapeAttribute, [
('positions', np.float32, (0, 0), 2, True,
'Position of each particle'),
('orientations', np.float32, (1, 0, 0, 0), 2, True,
'Orientation quaternion of each particle'),
('colors', np.float32, (.5, .5, .5, 1), 2, True,
'Color, RGBA, [0, 1] for each particle'),
('vertices', np.float32, (0, 0), 2, False,
'Vertices in local coordinates for the interior (non-rounded) shape, '
'to be replicated for each particle (CCW order)'),
('outline', np.float32, 0, 0, False,
'Outline width for all particles'),
('radius', np.float32, 0.1, 0, False,
'Rounding radius for all particles')
]))
@property
def angles(self):
"""Orientation of each particle, in radians"""
quats = self.orientations
return 2*np.arctan2(quats[:, 3], quats[:, 0])
@angles.setter
def angles(self, value):
halfthetas = 0.5*np.atleast_2d(value).reshape((-1, 1))
real = np.cos(halfthetas)
imag = np.sin(halfthetas)
zeros = np.zeros_like(real)
quats = np.hstack([real, zeros, zeros, imag]).astype(np.float32)
self.orientations = quats