import numpy as np
import holoviews as hv
from holoviews import opts
from scipy.spatial import Delaunay

hv.extension('bokeh')

n_verts = 100
pts = np.random.randint(1, n_verts, (n_verts, 2))
tris = Delaunay(pts)

trimesh = hv.TriMesh((tris.simplices, pts))
trimesh

hv.TriMesh.from_vertices(np.random.randn(100, 2))

trimesh.nodes + trimesh.edgepaths

# First create the x and y coordinates of the points.
n_angles = 36
n_radii = 8
min_radius = 0.25
radii = np.linspace(min_radius, 0.95, n_radii)

angles = np.linspace(0, 2*np.pi, n_angles, endpoint=False)
angles = np.repeat(angles[..., np.newaxis], n_radii, axis=1)
angles[:, 1::2] += np.pi/n_angles

x = (radii*np.cos(angles)).flatten()
y = (radii*np.sin(angles)).flatten()
z = (np.cos(radii)*np.cos(angles*3.0)).flatten()
nodes = np.column_stack([x, y, z])

# Apply Delaunay triangulation
delaunay = Delaunay(np.column_stack([x, y]))

# Mask off unwanted triangles.
xmid = x[delaunay.simplices].mean(axis=1)
ymid = y[delaunay.simplices].mean(axis=1)
mask = np.where(xmid*xmid + ymid*ymid < min_radius*min_radius, 1, 0)
simplices = delaunay.simplices[np.logical_not(mask)]

nodes = hv.Points(nodes, vdims='z')
hv.TriMesh((simplices, nodes))

trimesh = hv.TriMesh((simplices, nodes))

trimesh.opts(
    opts.TriMesh(cmap='viridis', edge_color='z', filled=True, height=400, 
                 inspection_policy='edges', tools=['hover'], width=400))