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# -*- coding: utf-8 -*-
# -----------------------------------------------------------------------------
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
# -----------------------------------------------------------------------------
import numpy as np
from .triangulation import Triangulation
class PolygonData(object):
"""Polygon class for data handling
Parameters
----------
vertices : (Nv, 3) array
Vertex coordinates. If faces is not specified, then this will instead
be interpreted as (Nf, 3, 3) array of coordinates.
edges : (Nv, 2) array
Constraining edges specified by vertex indices.
faces : (Nf, 3) array
Indexes into the vertex array.
Notes
-----
All arguments are optional.
"""
def __init__(self, vertices=None, edges=None, faces=None):
self._vertices = vertices
self._edges = edges
self._faces = faces
self._convex_hull = None
@property
def faces(self):
"""Return an array (Nf, 3) of vertex indexes, three per triangular
face in the mesh.
If faces have not been computed for this mesh, the function
computes them.
If no vertices or faces are specified, the function returns None.
"""
if self._faces is None:
if self._vertices is None:
return None
self.triangulate()
return self._faces
@faces.setter
def faces(self, f):
"""If vertices and faces are incompatible, this will generate vertices
from these faces and set them.
"""
self._faces = f
@property
def vertices(self):
"""Return an array (Nf, 3) of vertices.
If only faces exist, the function computes the vertices and
returns them.
If no vertices or faces are specified, the function returns None.
"""
if self._faces is None:
if self._vertices is None:
return None
self.triangulate()
return self._vertices
@vertices.setter
def vertices(self, v):
"""If vertices and faces are incompatible, this will generate faces
from these vertices and set them.
"""
self._vertices = v
@property
def edges(self):
"""Return an array (Nv, 2) of vertex indices.
If no vertices or faces are specified, the function returns None.
"""
return self._edges
@edges.setter
def edges(self, e):
"""Ensures that all edges are valid."""
self._edges = e
@property
def convex_hull(self):
"""Return an array of vertex indexes representing the convex hull.
If faces have not been computed for this mesh, the function
computes them.
If no vertices or faces are specified, the function returns None.
"""
if self._faces is None:
if self._vertices is None:
return None
self.triangulate()
return self._convex_hull
def triangulate(self):
"""
Triangulates the set of vertices and stores the triangles in faces and
the convex hull in convex_hull.
"""
npts = self._vertices.shape[0]
if np.any(self._vertices[0] != self._vertices[1]):
# start != end, so edges must wrap around to beginning.
edges = np.empty((npts, 2), dtype=np.uint32)
edges[:, 0] = np.arange(npts)
edges[:, 1] = edges[:, 0] + 1
edges[-1, 1] = 0
else:
# start == end; no wrapping required.
edges = np.empty((npts-1, 2), dtype=np.uint32)
edges[:, 0] = np.arange(npts)
edges[:, 1] = edges[:, 0] + 1
tri = Triangulation(self._vertices, edges)
tri.triangulate()
return tri.pts, tri.tris
def add_vertex(self, vertex):
"""
Adds given vertex and retriangulates to generate new faces.
Parameters
----------
vertex : array-like
The vertex to add.
"""
raise NotImplementedError
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