quaternion.h

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//
// Copyright 2016 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#ifndef PXR_BASE_GF_QUATERNION_H
#define PXR_BASE_GF_QUATERNION_H


#include "pxr/pxr.h"
#include "pxr/base/gf/api.h"
#include "pxr/base/gf/vec3d.h"
#include "pxr/base/tf/hash.h"

#include <iosfwd>

PXR_NAMESPACE_OPEN_SCOPE

class GfQuaternion
{
  public:

    GfQuaternion() {
    }

    explicit GfQuaternion(int realVal)
        : _real(realVal), _imaginary(0)
    {
    }

    GfQuaternion(double real, const GfVec3d &imaginary)
        : _real(real), _imaginary(imaginary) {
    }

    void                SetReal(double real) {
        _real  = real;
    }

    void                SetImaginary(const GfVec3d &imaginary) {
        _imaginary  = imaginary;
    }

    double              GetReal() const {
        return _real;
    }

    const GfVec3d &     GetImaginary() const {
        return _imaginary;
    }

    static GfQuaternion GetZero() {
        return GfQuaternion(0.0, GfVec3d(0.0, 0.0, 0.0));
    }

    static GfQuaternion GetIdentity() {
        return GfQuaternion(1.0, GfVec3d(0.0, 0.0, 0.0));
    }

    GF_API
    double              GetLength() const;

    GF_API
    GfQuaternion        GetNormalized(double eps = GF_MIN_VECTOR_LENGTH) const;

    GF_API
    double              Normalize(double eps = GF_MIN_VECTOR_LENGTH);

    GF_API
    GfQuaternion        GetInverse() const;

    friend inline size_t hash_value(const GfQuaternion &q) {
        return TfHash::Combine(q.GetReal(), q.GetImaginary());
    }

    bool                operator ==(const GfQuaternion &q) const {
        return (GetReal()      == q.GetReal() &&
                GetImaginary() == q.GetImaginary());
    }

    bool                operator !=(const GfQuaternion &q) const {
        return ! (*this == q);
    }

    GF_API
    GfQuaternion &      operator *=(const GfQuaternion &q);

    GF_API
    GfQuaternion &      operator *=(double s);

    GfQuaternion &      operator /=(double s) {
        return (*this) *= 1.0 / s;
    }

    GfQuaternion &      operator +=(const GfQuaternion &q)  {
        _real      += q._real;
        _imaginary += q._imaginary;
        return *this;
    }

    GfQuaternion &      operator -=(const GfQuaternion &q)  {
        _real      -= q._real;
        _imaginary -= q._imaginary;
        return *this;
    }

    friend GfQuaternion operator +(const GfQuaternion &q1,
                    const GfQuaternion &q2) {
        GfQuaternion qt = q1;
        return qt += q2;
    }

    friend GfQuaternion operator -(const GfQuaternion &q1,
                    const GfQuaternion &q2) {
        GfQuaternion qt = q1;
        return qt -= q2;
    }

    friend GfQuaternion operator *(const GfQuaternion &q1,
                    const GfQuaternion &q2) {
        GfQuaternion qt  = q1;
        return       qt *= q2;
    }

    friend GfQuaternion operator *(const GfQuaternion &q, double s) {
        GfQuaternion qt  = q;
        return       qt *= s;
    }

    friend GfQuaternion operator *(double s, const GfQuaternion &q) {
        GfQuaternion qt  = q;
        return       qt *= s;
    }

    friend GfQuaternion operator /(const GfQuaternion &q, double s) {
        GfQuaternion qt  = q;
        return       qt /= s;
    }

    GF_API
    friend GfQuaternion GfSlerp(double alpha,
                                const GfQuaternion& q0,
                                const GfQuaternion& q1);

    // TODO Remove this legacy alias/overload.
    friend GF_API GfQuaternion GfSlerp(const GfQuaternion& q0,
                                       const GfQuaternion& q1,
                                       double alpha);

  private:
    double              _real;
    GfVec3d             _imaginary;

    double              _GetLengthSquared() const {
        return (_real * _real + GfDot(_imaginary, _imaginary));
    }
};

// Friend functions must be declared.
GF_API GfQuaternion GfSlerp(double alpha, const GfQuaternion& q0, const GfQuaternion& q1);
GF_API GfQuaternion GfSlerp(const GfQuaternion& q0, const GfQuaternion& q1, double alpha);

GF_API std::ostream& operator<<(std::ostream& out, const GfQuaternion& q);


inline double
GfDot(const GfQuaternion &q1, const GfQuaternion &q2) {
    return  (q1.GetReal() * q2.GetReal()) + GfDot(q1.GetImaginary(), q2.GetImaginary());
}

PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_BASE_GF_QUATERNION_H