1 #include <stdio.h>

2 #include <math.h>

3 #include "quat.h"

4

5 void quat_print(FILE *fp, quat_t q)

6 {

7 fprintf(fp, "([ %.4f %.4f %.4f ] %.4f)", q.x, q.y, q.z, q.w);

8 }

9

10 quat_t quat_rotate(quat_t q, scalar_t angle, scalar_t x, scalar_t y, scalar_t z)

11 {

12 quat_t rq;

13 scalar_t half_angle = angle * 0.5;

14 scalar_t sin_half = sin(half_angle);

15

16 rq.w = cos(half_angle);

17 rq.x = x * sin_half;

18 rq.y = y * sin_half;

19 rq.z = z * sin_half;

20

21 return quat_mul(q, rq);

22 }

23

24 quat_t quat_rotate_quat(quat_t q, quat_t rotq)

25 {

26 return quat_mul(quat_mul(rotq, q), quat_conjugate(rotq));

27 }

28

29 quat_t quat_slerp(quat_t q1, quat_t q2, scalar_t t)

30 {

31 quat_t res;

32 scalar_t angle = acos(q1.w * q2.w + q1.x * q2.x + q1.y * q2.y + q1.z * q2.z);

33 scalar_t a = sin((1.0f - t) * angle);

34 scalar_t b = sin(t * angle);

35 scalar_t c = sin(angle);

36

37 res.x = (q1.x * a + q2.x * b) / c;

38 res.y = (q1.y * a + q2.y * b) / c;

39 res.z = (q1.z * a + q2.z * b) / c;

40 res.w = (q1.w * a + q2.w * b) / c;

41 return quat_normalize(res);

42 }