| 0,0 → 1,89 |
|---|
| /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- |
| /* |
| * quaternion.cpp |
| * Copyright (C) Andrew Tridgell 2012 |
| * |
| * 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/>. |
| */ |
| |
| #include "AP_Math.h" |
| |
| // return the rotation matrix equivalent for this quaternion |
| void Quaternion::rotation_matrix(Matrix3f &m) |
| { |
| float q3q3 = q3 * q3; |
| float q3q4 = q3 * q4; |
| float q2q2 = q2 * q2; |
| float q2q3 = q2 * q3; |
| float q2q4 = q2 * q4; |
| float q1q2 = q1 * q2; |
| float q1q3 = q1 * q3; |
| float q1q4 = q1 * q4; |
| float q4q4 = q4 * q4; |
| |
| m.a.x = 1-2*(q3q3 + q4q4); |
| m.a.y = 2*(q2q3 - q1q4); |
| m.a.z = 2*(q2q4 + q1q3); |
| m.b.x = 2*(q2q3 + q1q4); |
| m.b.y = 1-2*(q2q2 + q4q4); |
| m.b.z = 2*(q3q4 - q1q2); |
| m.c.x = 2*(q2q4 - q1q3); |
| m.c.y = 2*(q3q4 + q1q2); |
| m.c.z = 1-2*(q2q2 + q3q3); |
| } |
| |
| // convert a vector from earth to body frame |
| void Quaternion::earth_to_body(Vector3f &v) |
| { |
| Matrix3f m; |
| // we reverse z before and afterwards because of the differing |
| // quaternion conventions from APM conventions. |
| v.z = -v.z; |
| rotation_matrix(m); |
| v = m * v; |
| v.z = -v.z; |
| } |
| |
| // create a quaternion from Euler angles |
| void Quaternion::from_euler(float roll, float pitch, float yaw) |
| { |
| float cr2 = cos(roll*0.5); |
| float cp2 = cos(pitch*0.5); |
| float cy2 = cos(yaw*0.5); |
| float sr2 = sin(roll*0.5); |
| float sp2 = sin(pitch*0.5); |
| float sy2 = sin(yaw*0.5); |
| |
| q1 = cr2*cp2*cy2 + sr2*sp2*sy2; |
| q2 = sr2*cp2*cy2 - cr2*sp2*sy2; |
| q3 = cr2*sp2*cy2 + sr2*cp2*sy2; |
| q4 = cr2*cp2*sy2 - sr2*sp2*cy2; |
| } |
| |
| // create eulers from a quaternion |
| void Quaternion::to_euler(float *roll, float *pitch, float *yaw) |
| { |
| if (roll) { |
| *roll = (atan2(2.0*(q1*q2 + q3*q4), |
| 1 - 2.0*(q2*q2 + q3*q3))); |
| } |
| if (pitch) { |
| // we let safe_asin() handle the singularities near 90/-90 in pitch |
| *pitch = safe_asin(2.0*(q1*q3 - q4*q2)); |
| } |
| if (yaw) { |
| *yaw = atan2(2.0*(q1*q4 + q2*q3), |
| 1 - 2.0*(q3*q3 + q4*q4)); |
| } |
| } |