# -*- coding: utf-8 -*-
# -----------------------------------------------------------------------------
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
# -----------------------------------------------------------------------------
# vispy: gallery 2
"""
Isocurve for Triangular Mesh 
============================

This example demonstrates isocurve for triangular mesh with vertex data.
"""

import numpy as np

from vispy import app, scene

from vispy.geometry.generation import create_sphere

import sys

# Create a canvas with a 3D viewport
canvas = scene.SceneCanvas(keys='interactive',
                           title='Isocurve for Triangular Mesh Example')
canvas.show()
view = canvas.central_widget.add_view()

cols = 10
rows = 10
radius = 2
nbr_level = 20
mesh = create_sphere(cols, rows, radius=radius)
vertices = mesh.get_vertices()
tris = mesh.get_faces()

cl = np.linspace(-radius, radius, nbr_level+2)[1:-1]

scene.visuals.Isoline(vertices=vertices, tris=tris, data=vertices[:, 2],
                      levels=cl, color_lev='winter', parent=view.scene)

# Add a 3D axis to keep us oriented
scene.visuals.XYZAxis(parent=view.scene)

view.camera = scene.TurntableCamera()
view.camera.set_range((-1, 1), (-1, 1), (-1, 1))

if __name__ == '__main__' and sys.flags.interactive == 0:
    app.run()
