ardupilot/Tools/mavproxy_modules/lib/geodesic_grid.py

65 lines
2.0 KiB
Python

# Copyright (C) 2016 Intel Corporation. All rights reserved.
#
# This file is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This file is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
'''
This module takes libraries/AP_Math/AP_GeodesicGrid.h reference for defining
the geodesic sections.
'''
import math
from scipy.constants import golden as g
_first_half = (
((-g, 1, 0), (-1, 0,-g), (-g,-1, 0)),
((-1, 0,-g), (-g,-1, 0), ( 0,-g,-1)),
((-g,-1, 0), ( 0,-g,-1), ( 0,-g, 1)),
((-1, 0,-g), ( 0,-g,-1), ( 1, 0,-g)),
(( 0,-g,-1), ( 0,-g, 1), ( g,-1, 0)),
(( 0,-g,-1), ( 1, 0,-g), ( g,-1, 0)),
(( g,-1, 0), ( 1, 0,-g), ( g, 1, 0)),
(( 1, 0,-g), ( g, 1, 0), ( 0, g,-1)),
(( 1, 0,-g), ( 0, g,-1), (-1, 0,-g)),
(( 0, g,-1), (-g, 1, 0), (-1, 0,-g)),
)
_second_half = tuple(
((-xa, -ya, -za), (-xb, -yb, -zb), (-xc, -yc, -zc))
for (xa, ya, za), (xb, yb, zb), (xc, yc, zc) in _first_half
)
triangles = _first_half + _second_half
def _midpoint_projection(a, b):
xa, ya, za = a
xb, yb, zb = b
s = _midpoint_projection.scale
return s * (xa + xb), s * (ya + yb), s * (za + zb)
radius = math.sqrt(1 + g**2)
# radius / (length of two vertices of an icosahedron triangle)
_midpoint_projection.scale = radius / (2 * g)
sections_triangles = ()
for a, b, c in triangles:
ma = _midpoint_projection(a, b)
mb = _midpoint_projection(b, c)
mc = _midpoint_projection(c, a)
sections_triangles += (
(ma, mb, mc),
( a, ma, mc),
(ma, b, mb),
(mc, mb, c),
)