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# -*- coding: utf-8 -*-
# vispy: gallery 30
# -----------------------------------------------------------------------------
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
# -----------------------------------------------------------------------------
""" Terrain generation using diamond-square alogrithm
and Scipy for Delaunay triangulation
"""
from vispy import gloo
from vispy import app
from vispy.util.transforms import perspective, translate, rotate
import numpy as np
from scipy.spatial import Delaunay
# Arrays for storing generated points and triangles
points = []
triangles = []
height = 0.0
def generate_terrain(r_min, r_max, c_min, c_max, disp):
"""Recursively generates terrain using diamond-square algorithm
and stores the vertices in points
"""
a = points[r_min, c_min, 2]
b = points[r_min, c_max, 2]
c = points[r_max, c_min, 2]
d = points[r_max, c_max, 2]
r_mid = (r_min + r_max) // 2
c_mid = (c_min + c_max) // 2
e = (a+b+c+d)/4 + np.random.uniform(0, disp)
points[r_mid, c_mid, 2] = e
points[r_min, c_mid, 2] = (a + b + e)/3 + np.random.uniform(0, disp)
points[r_max, c_mid, 2] = (c + d + e)/3 + np.random.uniform(0, disp)
points[r_mid, c_min, 2] = (a + c + e)/3 + np.random.uniform(0, disp)
points[r_mid, c_max, 2] = (b + d + e)/3 + np.random.uniform(0, disp)
new_disp = disp * (2 ** (-0.5))
if (r_mid - r_min > 1 or c_mid - c_min > 1):
generate_terrain(r_min, r_mid, c_min, c_mid, new_disp)
if (r_max - r_mid > 1 or c_mid - c_min > 1):
generate_terrain(r_mid, r_max, c_min, c_mid, new_disp)
if (r_mid - r_min > 1 or c_max - c_mid > 1):
generate_terrain(r_min, r_mid, c_mid, c_max, new_disp)
if (r_max - r_mid > 1 or c_max - c_mid > 1):
generate_terrain(r_mid, r_max, c_mid, c_max, new_disp)
def generate_points(length=3):
"""Generates points via recursive function and generate triangles using
Scipy Delaunay triangulation
Parameters
----------
length : int
(2 ** length + 1 by 2 ** length + 1) number of points is generated
"""
print("Points are being generated...")
global points, triangles, height
size = 2**(length) + 1
points = np.indices((size, size, 1)).T[0].transpose((1, 0, 2))
points = points.astype(np.float32)
generate_terrain(0, size-1, 0, size-1, length)
height = length
points = np.resize(points, (size*size, 3))
points2 = np.delete(points, 2, 1)
tri = Delaunay(points2)
triangles = points[tri.simplices]
triangles = np.vstack(triangles)
print("Points successfully generated.")
VERT_SHADER = """
uniform float u_height;
uniform mat4 u_model;
uniform mat4 u_view;
uniform mat4 u_projection;
attribute vec3 a_position;
varying vec4 v_color;
void main (void) {
gl_Position = u_projection * u_view * u_model * vec4(a_position, 1.0);
v_color = vec4(0.0, a_position[2] * a_position[2] / (u_height * u_height
* u_height), 0.1, 1.0);
}
"""
FRAG_SHADER = """
varying vec4 v_color;
void main()
{
gl_FragColor = v_color;
}
"""
class Canvas(app.Canvas):
def __init__(self):
app.Canvas.__init__(self, keys='interactive')
self.program = gloo.Program(VERT_SHADER, FRAG_SHADER)
# Sets the view to an appropriate position over the terrain
self.default_view = np.array([[0.8, 0.2, -0.48, 0],
[-0.5, 0.3, -0.78, 0],
[-0.01, 0.9, -0.3, 0],
[-4.5, -21.5, -7.4, 1]],
dtype=np.float32)
self.view = self.default_view
self.model = np.eye(4, dtype=np.float32)
self.projection = np.eye(4, dtype=np.float32)
self.translate = [0, 0, 0]
self.rotate = [0, 0, 0]
self.program['u_height'] = height
self.program['u_model'] = self.model
self.program['u_view'] = self.view
self.program['a_position'] = gloo.VertexBuffer(triangles)
self.activate_zoom()
gloo.set_state(clear_color='black', depth_test=True)
self.show()
def on_key_press(self, event):
"""Controls -
a(A) - move left
d(D) - move right
w(W) - move up
s(S) - move down
x/X - rotate about x-axis cw/anti-cw
y/Y - rotate about y-axis cw/anti-cw
z/Z - rotate about z-axis cw/anti-cw
space - reset view
p(P) - print current view
i(I) - zoom in
o(O) - zoom out
"""
self.translate = [0, 0, 0]
self.rotate = [0, 0, 0]
if(event.text == 'p' or event.text == 'P'):
print(self.view)
elif(event.text == 'd' or event.text == 'D'):
self.translate[0] = 0.3
elif(event.text == 'a' or event.text == 'A'):
self.translate[0] = -0.3
elif(event.text == 'w' or event.text == 'W'):
self.translate[1] = 0.3
elif(event.text == 's' or event.text == 'S'):
self.translate[1] = -0.3
elif(event.text == 'o' or event.text == 'O'):
self.translate[2] = 0.3
elif(event.text == 'i' or event.text == 'I'):
self.translate[2] = -0.3
elif(event.text == 'x'):
self.rotate = [1, 0, 0]
elif(event.text == 'X'):
self.rotate = [-1, 0, 0]
elif(event.text == 'y'):
self.rotate = [0, 1, 0]
elif(event.text == 'Y'):
self.rotate = [0, -1, 0]
elif(event.text == 'z'):
self.rotate = [0, 0, 1]
elif(event.text == 'Z'):
self.rotate = [0, 0, -1]
elif(event.text == ' '):
self.view = self.default_view
self.view = self.view.dot(
translate(-np.array(self.translate)).dot(
rotate(self.rotate[0], (1, 0, 0)).dot(
rotate(self.rotate[1], (0, 1, 0)).dot(
rotate(self.rotate[2], (0, 0, 1))))))
self.program['u_view'] = self.view
self.update()
def on_resize(self, event):
self.activate_zoom()
def activate_zoom(self):
gloo.set_viewport(0, 0, *self.physical_size)
self.projection = perspective(60.0, self.size[0] /
float(self.size[1]), 1.0, 100.0)
self.program['u_projection'] = self.projection
def on_draw(self, event):
# Clear
gloo.clear(color=True, depth=True)
# Draw
self.program.draw('triangles')
generate_points(8)
if __name__ == '__main__':
c = Canvas()
app.run()
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