annotate libs/vmath/quat_c.c @ 34:634c7f7c1f0f
the text blur distance was too much man
author |
John Tsiombikas <nuclear@mutantstargoat.com> |
date |
Fri, 09 Sep 2011 00:31:54 +0300 |
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ff055bff6a15 |
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1 #include <stdio.h>
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2 #include <math.h>
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3 #include "quat.h"
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4
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5 void quat_print(FILE *fp, quat_t q)
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6 {
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7 fprintf(fp, "([ %.4f %.4f %.4f ] %.4f)", q.x, q.y, q.z, q.w);
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8 }
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9
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10 quat_t quat_rotate(quat_t q, scalar_t angle, scalar_t x, scalar_t y, scalar_t z)
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11 {
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12 quat_t rq;
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13 scalar_t half_angle = angle * 0.5;
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14 scalar_t sin_half = sin(half_angle);
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15
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16 rq.w = cos(half_angle);
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17 rq.x = x * sin_half;
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18 rq.y = y * sin_half;
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19 rq.z = z * sin_half;
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20
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21 return quat_mul(q, rq);
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22 }
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23
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24 quat_t quat_rotate_quat(quat_t q, quat_t rotq)
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25 {
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26 return quat_mul(quat_mul(rotq, q), quat_conjugate(rotq));
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27 }
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28
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29 quat_t quat_slerp(quat_t q1, quat_t q2, scalar_t t)
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30 {
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31 quat_t res;
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32 scalar_t angle = acos(q1.w * q2.w + q1.x * q2.x + q1.y * q2.y + q1.z * q2.z);
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33 scalar_t a = sin((1.0f - t) * angle);
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34 scalar_t b = sin(t * angle);
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35 scalar_t c = sin(angle);
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36
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37 res.x = (q1.x * a + q2.x * b) / c;
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38 res.y = (q1.y * a + q2.y * b) / c;
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39 res.z = (q1.z * a + q2.z * b) / c;
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40 res.w = (q1.w * a + q2.w * b) / c;
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41 return quat_normalize(res);
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42 }
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