1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* ftm_mat4rotate.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: charles <charles.cabergs@gmail.com> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2020/05/12 11:44:18 by charles #+# #+# */
/* Updated: 2020/05/12 19:52:55 by charles ### ########.fr */
/* */
/* ************************************************************************** */
#include "libftm_mat4.h"
/*
** Rotation axis/vector [x, y, z]
**
** 1st column:
** | cos(θ) + x^2 (1 − cos(θ)) |
** | y x (1 − cos(θ)) + z sin(θ) |
** | z x (1 − cos(θ)) − y sin(θ) |
** | 0 |
**
** 2nd column:
** | x y (1 − cos(θ)) − z sin(θ) |
** | cos(θ) + y^2 (1 − cos(θ)) |
** | z y (1 − cos(θ)) + x sin(θ) |
** | 0 |
**
** 3rd column:
** | x z (1 − cos(θ)) + y sin(θ) |
** | y z (1 − cos(θ)) − x sin(θ) |
** | cos(θ) + z^2 (1 − cos(θ)) |
** | 0 |
*/
t_ftmmat4 *ftm_mat4rotate(t_ftmmat4 *mat4, float theta, t_ftmvec3 *axis)
{
float x;
float y;
float z;
float sin_t;
float cos_t;
float m_cos_t;
t_ftmmat4 rot;
x = axis->v[0];
y = axis->v[1];
z = axis->v[2];
sin_t = sinf(theta);
cos_t = cosf(theta);
m_cos_t = 1.0 - cos_t;
ftm_mat4init_eye(&rot, 1.0);
ftm_mat4set(&rot, 0, 0, cos_t + x * x * m_cos_t);
ftm_mat4set(&rot, 1, 0, y * x * m_cos_t + z * sin_t);
ftm_mat4set(&rot, 2, 0, z * x * m_cos_t - y * sin_t);
ftm_mat4set(&rot, 3, 0, 0.0);
ftm_mat4set(&rot, 0, 1, x * y * m_cos_t - z * sin_t);
ftm_mat4set(&rot, 1, 1, cos_t + y * y * m_cos_t);
ftm_mat4set(&rot, 2, 1, z * y * m_cos_t + x * sin_t);
ftm_mat4set(&rot, 3, 1, 0.0);
ftm_mat4set(&rot, 0, 2, x * z * m_cos_t + y * sin_t);
ftm_mat4set(&rot, 1, 2, y * z * m_cos_t - x * sin_t);
ftm_mat4set(&rot, 2, 2, cos_t + z * z * m_cos_t);
ftm_mat4set(&rot, 3, 2, 0.0);
ftm_mat4mul(mat4, &rot);
return (mat4);
}
|
