import math
import numpy  as np
import mayavi.mlab as mlab
import pickle

    # The following three lines will load the "pickled" arrays V and F from the
    # pickle file dino.pkl. V represents the vertices of the model as Nx3 matrix,
    # while N is the number of vertices the model consists of. F represent the
    # faces (here triangles of the model). F is also a Nx3 matrix, while here N
    # represents the number of the faces the model.
    fid = open('dino.pkl', 'rb')
    (V, F) = pickle.load(fid)
    fid.close()

    # a small wrapper function around mlab's triangular_mesh
    # input are the face-vertex indices inside an (M x 3) array F
    # and the vertices in a (N x 3) array V
    def trimesh(F, V, new_figure=True):
        if new_figure:
            mlab.figure()
            mlab.triangular_mesh(V[:,0], V[:,1] , V[:,2] , F)
            mlab.show()


    # small helper function that is used to visualize the coordinate axes
    def draw_axes():
        mlab.points3d(1, 0, 0, 1, scale_factor=0.1, color=(1, 0, 0))
        mlab.points3d(0, 1, 0, 1, scale_factor=0.1, color=(0, 1, 0))
        mlab.points3d(0, 0, 1, 1, scale_factor=0.1, color=(0, 0, 1))
        mlab.plot3d([0, 1], [0, 0], [0, 0])
        mlab.plot3d([0, 0], [0, 1], [0, 0])
        mlab.plot3d([0, 0], [0, 0], [0, 1])


    # show dino triangle mesh
    draw_axes()
    trimesh(F, V)