Slightly less naive mesh represenation

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 __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])
        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)