Mesh representation - with edges.

facelist.py

# if you can't rely on euclid, what can you rely on?
import euclid
from euclid import Vector3


class Mesh:
	def __init__(self, vertices=[], faces=[]):
		"""Initialises a vertex with a list of faces. Vertex array is a list of Vector3. Face array is a list of 3 tuple indexes into vertex array."""
		self.vertex_list = vertices
		self.face_list = faces

	def __len__(self):
		"""Returns number of vertices in a mesh"""
		return len(self.face_list) * 3

	def vertices(self):
		"""Iterate over the vertices in the mesh"""
		for v in self.vertex_list:
			yield v

	def faces(self):
		"""Iterate over the faces in the mesh"""
		for face in self.face_list:
			a, b, c = face
			yield (self.vertex_list[a], self.vertex_list[b], self.vertex_list[c])

	def edges(self):
		"""Iterate over the edges in the faces of the mesh"""
		for face in self.face_list:
			e0 = [self.vertex_list[face[0]], self.vertex_list[face[1]]]
			yield(tuple(e0))
			e1 = [self.vertex_list[face[1]], self.vertex_list[face[2]]]
			yield(tuple(e1))
			e2 = [self.vertex_list[face[2]], self.vertex_list[face[0]]]
			yield(tuple(e2))

	def __str__(self):
		"""Print a readable description of the mesh"""
		result = "Mesh with {0} vertices and {1} faces\n".format(
			len(self), len(self.face_list))
		for face_index, face in enumerate(self.faces()):
			result += "Face {0} :({1}, {2}, {3})\n".format(face_index,
														   face[0], face[1], face[2])
		for edge_index, edge in enumerate(self.edges()):
			a, b = edge[0], edge[1]
			result += "Edge {0} of Face {1} :({2}, {3})\n".format(edge_index %
			                                  3, edge_index // 3, a, b)
		return result


if __name__ == "__main__":
	cube_mesh=Mesh(vertices=[
		# face vertices
		Vector3(-1.0, -1.0, -1.0),
		Vector3(-1.0, 1.0, -1.0),
		Vector3(1.0, 1.0, -1.0),
		Vector3(1.0, -1.0, -1.0),
		Vector3(-1.0, -1.0, 1.0),
		Vector3(-1.0, 1.0, 1.0),
		Vector3(1.0, 1.0, 1.0),
		Vector3(1.0, -1.0, 1.0),
		# edge vertices
		Vector3(-1.0, -1.0, -1.0),
		Vector3(-1.0, 1.0, -1.0),
		Vector3(1.0, 1.0, -1.0),
		Vector3(1.0, -1.0, -1.0),
		Vector3(-1.0, -1.0, 1.0),
		Vector3(-1.0, 1.0, 1.0),
		Vector3(1.0, 1.0, 1.0),
		Vector3(1.0, -1.0, 1.0)
	],
		faces=[
		# Front face
		(0, 1, 2),
		(0, 2, 3),
		# Back face
		(4, 6, 5),
		(4, 7, 6),
		# Left face
		(4, 5, 1),
		(4, 1, 0),
		# Right face
		(3, 2, 6),
		(3, 6, 7),
		# Top face
		(1, 5, 6),
		(1, 6, 2),
		# Bottom face
		(4, 0, 3),
		(4, 3, 7)
	])
	print(cube_mesh)