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> 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> 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> 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
