def generate_tube_meshes(path, closed=False, tube_points=10):
"""Generates list of mesh vertices and triangles from a path
Adapted from vispy.visuals.TubeVisual
https://github.com/vispy/vispy/blob/master/vispy/visuals/tube.py
Parameters
----------
path : (N, 3) array
Vertices specifying the path.
closed : bool
Bool which determines if the path is closed or not.
tube_points : int
The number of points in the circle-approximating polygon of the
tube's cross section.
Returns
----------
centers : (M, 3) array
Vertices of all triangles for the lines
offsets : (M, D) array
offsets of all triangles for the lines
triangles : (P, 3) array
Vertex indices that form the mesh triangles
"""
points = np.array(path).astype(float)
if closed and not np.all(points[0] == points[-1]):
points = np.concatenate([points, [points[0]]], axis=0)
tangents, normals, binormals = _frenet_frames(points, closed)
segments = len(points) - 1
# get the positions of each vertex
grid = np.zeros((len(points), tube_points, 3))
grid_off = np.zeros((len(points), tube_points, 3))
for i in range(len(points)):
pos = points[i]
normal = normals[i]
binormal = binormals[i]
# Add a vertex for each point on the circle
v = np.arange(tube_points, dtype=np.float) / tube_points * 2 * np.pi
cx = -1.0 * np.cos(v)
cy = np.sin(v)
grid[i] = pos
grid_off[i] = cx[:, np.newaxis] * normal + cy[:, np.newaxis] * binormal
# construct the mesh
indices = []
for i in range(segments):
for j in range(tube_points):
ip = (i + 1) % segments if closed else i + 1
jp = (j + 1) % tube_points
index_a = i * tube_points + j
index_b = ip * tube_points + j
index_c = ip * tube_points + jp
index_d = i * tube_points + jp
indices.append([index_a, index_b, index_d])
indices.append([index_b, index_c, index_d])
triangles = np.array(indices, dtype=np.uint32)
centers = grid.reshape(grid.shape[0] * grid.shape[1], 3)
offsets = grid_off.reshape(grid_off.shape[0] * grid_off.shape[1], 3)
return centers, offsets, triangles
def __init__(self,
points,
radius=1.0,
closed=False,
color='purple',
tube_points=8,
shading='smooth',
vertex_colors=None,
face_colors=None,
mode='triangles'):
points = np.array(points)
tangents, normals, binormals = _frenet_frames(points, closed)
segments = len(points) - 1
if not isinstance(radius, collections.Iterable):
radius = [radius] * len(points)
# get the positions of each vertex
grid = np.zeros((len(points), tube_points, 3))
for i in range(len(points)):
pos = points[i]
normal = normals[i]
binormal = binormals[i]
r = radius[i]
# Add a vertex for each point on the circle
v = np.arange(tube_points,
dtype=np.float) / tube_points * 2 * np.pi
cx = -1. * r * np.cos(v)
cy = r * np.sin(v)
grid[i] = (pos + cx[:, np.newaxis] * normal +
cy[:, np.newaxis] * binormal)
# construct the mesh
indices = []
for i in range(segments):
for j in range(tube_points):
ip = (i + 1) % segments if closed else i + 1
jp = (j + 1) % tube_points
index_a = i * tube_points + j
index_b = ip * tube_points + j
index_c = ip * tube_points + jp
index_d = i * tube_points + jp
indices.append([index_a, index_b, index_d])
indices.append([index_b, index_c, index_d])
vertices = grid.reshape(grid.shape[0] * grid.shape[1], 3)
color = ColorArray(color)
if vertex_colors is None:
point_colors = np.resize(color.rgba, (len(points), 4))
vertex_colors = np.repeat(point_colors, tube_points, axis=0)
indices = np.array(indices, dtype=np.uint32)
MeshVisual.__init__(self,
vertices,
indices,
vertex_colors=vertex_colors,
face_colors=face_colors,
shading=shading,
mode=mode)
