58 lines
1.6 KiB
C++
58 lines
1.6 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "Quaternion.h"
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#include "Matrix.h"
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#include "Tools.h"
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#include <algorithm>
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#include <ostream>
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#include <math.h>
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using namespace std;
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namespace mozilla {
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namespace gfx {
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std::ostream&
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operator<<(std::ostream& aStream, const Quaternion& aQuat)
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{
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return aStream << "< " << aQuat.x << " " << aQuat.y << " " << aQuat.z << " " << aQuat.w << ">";
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}
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void
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Quaternion::SetFromRotationMatrix(const Matrix4x4& m)
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{
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// see http://www.euclideanspace.com/maths/geometry/rotations/conversions/matrixToQuaternion/index.htm
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const Float trace = m._11 + m._22 + m._33;
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if (trace > 0.0) {
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const Float s = 0.5f / sqrt(trace + 1.0f);
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w = 0.25f / s;
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x = (m._32 - m._23) * s;
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y = (m._13 - m._31) * s;
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z = (m._21 - m._12) * s;
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} else if (m._11 > m._22 && m._11 > m._33) {
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const Float s = 2.0f * sqrt(1.0f + m._11 - m._22 - m._33);
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w = (m._32 - m._23) / s;
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x = 0.25f * s;
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y = (m._12 + m._21) / s;
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z = (m._13 + m._31) / s;
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} else if (m._22 > m._33) {
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const Float s = 2.0 * sqrt(1.0f + m._22 - m._11 - m._33);
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w = (m._13 - m._31) / s;
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x = (m._12 + m._21) / s;
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y = 0.25f * s;
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z = (m._23 + m._32) / s;
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} else {
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const Float s = 2.0 * sqrt(1.0f + m._33 - m._11 - m._22);
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w = (m._21 - m._12) / s;
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x = (m._13 + m._31) / s;
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y = (m._23 + m._32) / s;
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z = 0.25f * s;
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}
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}
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} // namespace gfx
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} // namespace mozilla
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