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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ANDROID_QUAT_H
#define ANDROID_QUAT_H
#include <math.h>
#include "vec.h"
#include "mat.h"
// -----------------------------------------------------------------------
namespace android {
// -----------------------------------------------------------------------
template <typename TYPE>
mat<TYPE, 3, 3> quatToMatrix(const vec<TYPE, 4>& q) {
mat<TYPE, 3, 3> R;
TYPE q0(q.w);
TYPE q1(q.x);
TYPE q2(q.y);
TYPE q3(q.z);
TYPE sq_q1 = 2 * q1 * q1;
TYPE sq_q2 = 2 * q2 * q2;
TYPE sq_q3 = 2 * q3 * q3;
TYPE q1_q2 = 2 * q1 * q2;
TYPE q3_q0 = 2 * q3 * q0;
TYPE q1_q3 = 2 * q1 * q3;
TYPE q2_q0 = 2 * q2 * q0;
TYPE q2_q3 = 2 * q2 * q3;
TYPE q1_q0 = 2 * q1 * q0;
R[0][0] = 1 - sq_q2 - sq_q3;
R[0][1] = q1_q2 - q3_q0;
R[0][2] = q1_q3 + q2_q0;
R[1][0] = q1_q2 + q3_q0;
R[1][1] = 1 - sq_q1 - sq_q3;
R[1][2] = q2_q3 - q1_q0;
R[2][0] = q1_q3 - q2_q0;
R[2][1] = q2_q3 + q1_q0;
R[2][2] = 1 - sq_q1 - sq_q2;
return R;
}
template <typename TYPE>
vec<TYPE, 4> matrixToQuat(const mat<TYPE, 3, 3>& R) {
// matrix to quaternion
struct {
inline TYPE operator()(TYPE v) {
return v < 0 ? 0 : v;
}
} clamp;
vec<TYPE, 4> q;
const float Hx = R[0].x;
const float My = R[1].y;
const float Az = R[2].z;
q.x = sqrtf( clamp( Hx - My - Az + 1) * 0.25f );
q.y = sqrtf( clamp(-Hx + My - Az + 1) * 0.25f );
q.z = sqrtf( clamp(-Hx - My + Az + 1) * 0.25f );
q.w = sqrtf( clamp( Hx + My + Az + 1) * 0.25f );
q.x = copysignf(q.x, R[2].y - R[1].z);
q.y = copysignf(q.y, R[0].z - R[2].x);
q.z = copysignf(q.z, R[1].x - R[0].y);
// guaranteed to be unit-quaternion
return q;
}
template <typename TYPE>
vec<TYPE, 4> normalize_quat(const vec<TYPE, 4>& q) {
vec<TYPE, 4> r(q);
if (r.w < 0) {
r = -r;
}
return normalize(r);
}
// -----------------------------------------------------------------------
typedef vec4_t quat_t;
// -----------------------------------------------------------------------
}; // namespace android
#endif /* ANDROID_QUAT_H */
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