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annotate libs/vmath/quat_c.c @ 43:73813c1176de

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author John Tsiombikas <nuclear@member.fsf.org>
date Fri, 14 Aug 2015 04:33:42 +0300
parents c0ae8e668447
children
rev   line source
nuclear@39 1 /*
nuclear@39 2 libvmath - a vector math library
nuclear@39 3 Copyright (C) 2004-2011 John Tsiombikas <nuclear@member.fsf.org>
nuclear@39 4
nuclear@39 5 This program is free software: you can redistribute it and/or modify
nuclear@39 6 it under the terms of the GNU Lesser General Public License as published
nuclear@39 7 by the Free Software Foundation, either version 3 of the License, or
nuclear@39 8 (at your option) any later version.
nuclear@39 9
nuclear@39 10 This program is distributed in the hope that it will be useful,
nuclear@39 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@39 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@39 13 GNU Lesser General Public License for more details.
nuclear@39 14
nuclear@39 15 You should have received a copy of the GNU Lesser General Public License
nuclear@39 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@39 17 */
nuclear@39 18
nuclear@39 19
nuclear@28 20 #include <stdio.h>
nuclear@28 21 #include <math.h>
nuclear@28 22 #include "quat.h"
nuclear@28 23
nuclear@28 24 void quat_print(FILE *fp, quat_t q)
nuclear@28 25 {
nuclear@28 26 fprintf(fp, "([ %.4f %.4f %.4f ] %.4f)", q.x, q.y, q.z, q.w);
nuclear@28 27 }
nuclear@28 28
nuclear@28 29 quat_t quat_rotate(quat_t q, scalar_t angle, scalar_t x, scalar_t y, scalar_t z)
nuclear@28 30 {
nuclear@28 31 quat_t rq;
nuclear@28 32 scalar_t half_angle = angle * 0.5;
nuclear@28 33 scalar_t sin_half = sin(half_angle);
nuclear@28 34
nuclear@28 35 rq.w = cos(half_angle);
nuclear@28 36 rq.x = x * sin_half;
nuclear@28 37 rq.y = y * sin_half;
nuclear@28 38 rq.z = z * sin_half;
nuclear@28 39
nuclear@28 40 return quat_mul(q, rq);
nuclear@28 41 }
nuclear@28 42
nuclear@28 43 quat_t quat_rotate_quat(quat_t q, quat_t rotq)
nuclear@28 44 {
nuclear@28 45 return quat_mul(quat_mul(rotq, q), quat_conjugate(rotq));
nuclear@28 46 }
nuclear@28 47
nuclear@28 48 quat_t quat_slerp(quat_t q1, quat_t q2, scalar_t t)
nuclear@28 49 {
nuclear@28 50 quat_t res;
nuclear@28 51 scalar_t angle = acos(q1.w * q2.w + q1.x * q2.x + q1.y * q2.y + q1.z * q2.z);
nuclear@28 52 scalar_t a = sin((1.0f - t) * angle);
nuclear@28 53 scalar_t b = sin(t * angle);
nuclear@28 54 scalar_t c = sin(angle);
nuclear@28 55
nuclear@28 56 res.x = (q1.x * a + q2.x * b) / c;
nuclear@28 57 res.y = (q1.y * a + q2.y * b) / c;
nuclear@28 58 res.z = (q1.z * a + q2.z * b) / c;
nuclear@28 59 res.w = (q1.w * a + q2.w * b) / c;
nuclear@28 60 return quat_normalize(res);
nuclear@28 61 }