1 /*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #ifndef ANDROID_QUAT_H
18 #define ANDROID_QUAT_H
19
20 #include <math.h>
21
22 #include "vec.h"
23 #include "mat.h"
24
25 // -----------------------------------------------------------------------
26 namespace android {
27 // -----------------------------------------------------------------------
28
29 template <typename TYPE>
quatToMatrix(const vec<TYPE,4> & q)30 mat<TYPE, 3, 3> quatToMatrix(const vec<TYPE, 4>& q) {
31 mat<TYPE, 3, 3> R;
32 TYPE q0(q.w);
33 TYPE q1(q.x);
34 TYPE q2(q.y);
35 TYPE q3(q.z);
36 TYPE sq_q1 = 2 * q1 * q1;
37 TYPE sq_q2 = 2 * q2 * q2;
38 TYPE sq_q3 = 2 * q3 * q3;
39 TYPE q1_q2 = 2 * q1 * q2;
40 TYPE q3_q0 = 2 * q3 * q0;
41 TYPE q1_q3 = 2 * q1 * q3;
42 TYPE q2_q0 = 2 * q2 * q0;
43 TYPE q2_q3 = 2 * q2 * q3;
44 TYPE q1_q0 = 2 * q1 * q0;
45 R[0][0] = 1 - sq_q2 - sq_q3;
46 R[0][1] = q1_q2 - q3_q0;
47 R[0][2] = q1_q3 + q2_q0;
48 R[1][0] = q1_q2 + q3_q0;
49 R[1][1] = 1 - sq_q1 - sq_q3;
50 R[1][2] = q2_q3 - q1_q0;
51 R[2][0] = q1_q3 - q2_q0;
52 R[2][1] = q2_q3 + q1_q0;
53 R[2][2] = 1 - sq_q1 - sq_q2;
54 return R;
55 }
56
57 template <typename TYPE>
matrixToQuat(const mat<TYPE,3,3> & R)58 vec<TYPE, 4> matrixToQuat(const mat<TYPE, 3, 3>& R) {
59 // matrix to quaternion
60
61 struct {
62 inline TYPE operator()(TYPE v) {
63 return v < 0 ? 0 : v;
64 }
65 } clamp;
66
67 vec<TYPE, 4> q;
68 const float Hx = R[0].x;
69 const float My = R[1].y;
70 const float Az = R[2].z;
71 q.x = sqrtf( clamp( Hx - My - Az + 1) * 0.25f );
72 q.y = sqrtf( clamp(-Hx + My - Az + 1) * 0.25f );
73 q.z = sqrtf( clamp(-Hx - My + Az + 1) * 0.25f );
74 q.w = sqrtf( clamp( Hx + My + Az + 1) * 0.25f );
75 q.x = copysignf(q.x, R[2].y - R[1].z);
76 q.y = copysignf(q.y, R[0].z - R[2].x);
77 q.z = copysignf(q.z, R[1].x - R[0].y);
78 // guaranteed to be unit-quaternion
79 return q;
80 }
81
82 template <typename TYPE>
normalize_quat(const vec<TYPE,4> & q)83 vec<TYPE, 4> normalize_quat(const vec<TYPE, 4>& q) {
84 vec<TYPE, 4> r(q);
85 if (r.w < 0) {
86 r = -r;
87 }
88 return normalize(r);
89 }
90
91 // -----------------------------------------------------------------------
92
93 typedef vec4_t quat_t;
94
95 // -----------------------------------------------------------------------
96 }; // namespace android
97
98 #endif /* ANDROID_QUAT_H */
99