istereo

view libs/vmath/quat_c.c @ 39:ff055bff6a15

copyright statements and stuff
author John Tsiombikas <nuclear@mutantstargoat.com>
date Sun, 11 Sep 2011 09:03:18 +0300
parents c0ae8e668447
children
line source
1 /*
2 libvmath - a vector math library
3 Copyright (C) 2004-2011 John Tsiombikas <nuclear@member.fsf.org>
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as published
7 by the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
20 #include <stdio.h>
21 #include <math.h>
22 #include "quat.h"
24 void quat_print(FILE *fp, quat_t q)
25 {
26 fprintf(fp, "([ %.4f %.4f %.4f ] %.4f)", q.x, q.y, q.z, q.w);
27 }
29 quat_t quat_rotate(quat_t q, scalar_t angle, scalar_t x, scalar_t y, scalar_t z)
30 {
31 quat_t rq;
32 scalar_t half_angle = angle * 0.5;
33 scalar_t sin_half = sin(half_angle);
35 rq.w = cos(half_angle);
36 rq.x = x * sin_half;
37 rq.y = y * sin_half;
38 rq.z = z * sin_half;
40 return quat_mul(q, rq);
41 }
43 quat_t quat_rotate_quat(quat_t q, quat_t rotq)
44 {
45 return quat_mul(quat_mul(rotq, q), quat_conjugate(rotq));
46 }
48 quat_t quat_slerp(quat_t q1, quat_t q2, scalar_t t)
49 {
50 quat_t res;
51 scalar_t angle = acos(q1.w * q2.w + q1.x * q2.x + q1.y * q2.y + q1.z * q2.z);
52 scalar_t a = sin((1.0f - t) * angle);
53 scalar_t b = sin(t * angle);
54 scalar_t c = sin(angle);
56 res.x = (q1.x * a + q2.x * b) / c;
57 res.y = (q1.y * a + q2.y * b) / c;
58 res.z = (q1.z * a + q2.z * b) / c;
59 res.w = (q1.w * a + q2.w * b) / c;
60 return quat_normalize(res);
61 }