UT_Quaternion.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * NAME:        UT library (C++)
 *
 * COMMENTS:    This class implements quaternions.
 *
 * WARNING:
 *      This class should NOT contain any virtual methods, nor should it
 *      define more member data. The size of UT_QuaternionF must always be 
 *      16 bytes (4 floats).
 *
 */

#pragma once

#ifndef __UT_Quaternion_h__
#define __UT_Quaternion_h__

#include "UT_API.h"
#include "UT_FixedVectorTraits.h"
#include "UT_Vector3.h"
#include "UT_Vector4.h"
#include "UT_VectorTypes.h" // IWYU pragma: export

#include <SYS/SYS_Inline.h>
#include <SYS/SYS_Math.h>
#include <SYS/SYS_Types.h>
#include <iosfwd>
#include <limits>
#include <stddef.h>

class UT_IStream;
class UT_JSONParser;
class UT_JSONValue;
class UT_JSONWriter;
class UT_XformOrder;

// Forward declaration
template <typename T> class UT_API UT_QuaternionT;

/// Perform component-wise SYSlerp of two quaternions
template <typename T>
inline UT_QuaternionT<T>
SYSlerp(const UT_QuaternionT<T> &q1, const UT_QuaternionT<T> &q2, T t);

/// Quaternion class
template <typename T>
class UT_API UT_QuaternionT
{
public:

    typedef T                    value_type;
    static constexpr int         tuple_size = 4;

                                 /// q = qx(i) + qy(j) + qz(k) + qw.
                                 UT_QuaternionT(T qx=0, T qy=0,
                                               T qz=0, T qw=0)
                                 {
                                     vec[0] = qx;  vec[1] = qy;
                                     vec[2] = qz;  vec[3] = qw;
                                 }
                                 UT_QuaternionT(const fpreal32 v[tuple_size])
                                 {
                                    vec[0] = v[0]; vec[1] = v[1];
                                    vec[2] = v[2]; vec[3] = v[3];
                                 }
                                 UT_QuaternionT(const fpreal64 v[tuple_size])
                                 {
                                    vec[0] = v[0]; vec[1] = v[1];
                                    vec[2] = v[2]; vec[3] = v[3];
                                 }
                                 UT_QuaternionT(const UT_Vector4T<T> &v)
                                 {
                                    vec[0] = v[0]; vec[1] = v[1];
                                    vec[2] = v[2]; vec[3] = v[3];
                                 }
                                 inline UT_QuaternionT(T angle, 
                                                const UT_Vector3T<T> &axis, 
                                                int donormalize=1);
                                 UT_QuaternionT(const UT_Vector3T<T> &rot,
                                               const UT_XformOrder &order)
                                 {
                                     updateFromEuler(rot, order);
                                 }
                                 
    typedef UT_QuaternionT<T>    ThisType;

    SYS_FORCE_INLINE             UT_QuaternionT(const ThisType &that) = default;
    SYS_FORCE_INLINE             UT_QuaternionT(ThisType &&that) = default;
    SYS_FORCE_INLINE ThisType   &operator=(const ThisType &that) = default;
    SYS_FORCE_INLINE ThisType   &operator=(ThisType &&that) = default;

    template <typename S> 
    inline UT_QuaternionT<T>(const UT_QuaternionT<S> &v)
    { vec[0] = v.x(); vec[1] = v.y(); vec[2] = v.z(); vec[3] = v.w(); }
    template <typename S> 
    inline UT_QuaternionT<T> &operator=(const UT_QuaternionT<S> &v)
    { vec[0] = v.x(); vec[1] = v.y(); vec[2] = v.z(); vec[3] = v.w(); return *this; }

    inline UT_QuaternionT<T>    &operator*=(const UT_QuaternionT<T> &q);
    inline UT_QuaternionT<T>    &operator*=(T scalar);
    inline UT_QuaternionT<T>    &operator/=(const UT_QuaternionT<T> &quat);
    inline UT_QuaternionT<T>    &operator/=(T scalar);
    inline UT_QuaternionT<T>    &operator+=(const UT_QuaternionT<T> &quat);
    inline bool                  operator==(const UT_QuaternionT<T> &quat) const;
    inline bool                  operator!=(const UT_QuaternionT<T> &quat) const;
    T                            operator()(int idx) const
                                 { return vec[idx]; }
    T                           &operator()(int idx)
                                 { return vec[idx]; }
    T                            operator[](int idx) const
                                 { return vec[idx]; }
    T                           &operator[](int idx)
                                 { return vec[idx]; }

    /// Does a comparison with a tolerance. This also returns true if
    /// quat.negated() is equal to us, unlike operator==().
    inline bool                  isEqual(const UT_QuaternionT<T> &quat,
                                         T tol = T(SYS_FTOLERANCE)) const;

    // The rotation this quaternion represents as a matrix
    void                         getRotationMatrix(UT_Matrix3 &mat) const;
    void                         getRotationMatrix(UT_DMatrix3 &mat) const;
    void                         getInverseRotationMatrix(UT_Matrix3 &mat) const;
    void                         getInverseRotationMatrix(UT_DMatrix3 &mat) const;

    void                         getTransformMatrix(UT_Matrix4 &mat) const;
    void                         getTransformMatrix(UT_DMatrix4 &mat) const;

    /// Interpolates between this quat (t==0) and the target (t==1)
    SYS_NO_DISCARD_RESULT
    UT_QuaternionT<T>            interpolate(const UT_QuaternionT<T> &target,
                                             T t, T b = 0.0f) const;
    /// Interpolates between the n quaternions in q, with weights w,
    /// to within tolerance tol.
    /// NOTE: The q's must be normalized, and the weights may need to sum to 1.
    void interpolate(const UT_QuaternionT<T> *q, const T *w, exint n, T tol = T(1e-6));

    /// Do component-wise lerp between this quat (t=0) and the target (t=1).
    void                         lerp(const UT_QuaternionT<T> &target, T t)
    {
        vec[0] = SYSlerp(vec[0], target.vec[0], t);
        vec[1] = SYSlerp(vec[1], target.vec[1], t);
        vec[2] = SYSlerp(vec[2], target.vec[2], t);
        vec[3] = SYSlerp(vec[3], target.vec[3], t);
    }
    /// Do component-wise lerp between this src (t=0) and dst (t=1).
    void                         lerp(const UT_QuaternionT<T> &src,
                                      const UT_QuaternionT<T> &dst,
                                      T t)
    {
        vec[0] = SYSlerp(src.vec[0], dst.vec[0], t);
        vec[1] = SYSlerp(src.vec[1], dst.vec[1], t);
        vec[2] = SYSlerp(src.vec[2], dst.vec[2], t);
        vec[3] = SYSlerp(src.vec[3], dst.vec[3], t);
    }

    void                         assign(T qx, T qy,
                                        T qz, T qw)
                                    {
                                        vec[0] = qx;  vec[1] = qy;
                                        vec[2] = qz;  vec[3] = qw;
                                    }
    void                         identity()
                                    {
                                        vec[0] = vec[1] = vec[2] = 0.0f;
                                        vec[3] = 1.0f;
                                    }
    void                         conjugate()
                                    {
                                        vec[0] = -vec[0];
                                        vec[1] = -vec[1];
                                        vec[2] = -vec[2];
                                    }
    void                         negate()
                                    {
                                        vec[0] = -vec[0];
                                        vec[1] = -vec[1];
                                        vec[2] = -vec[2];
                                        vec[3] = -vec[3];
                                    }
    T                           normal() const
                                    {
                                        return  vec[0] * vec[0] +
                                                vec[1] * vec[1] +
                                                vec[2] * vec[2] +
                                                vec[3] * vec[3];
                                    }
    void                         normalize()
                                    {
                                        T dn = normal();
                                        if (dn > std::numeric_limits<T>::min()
                                            && dn != 1.0)
                                        {
                                            dn = SYSsqrt(dn);
                                            *this /= dn;
                                        }
                                    }
    T                            length() const
                                    {
                                        return SYSsqrt(normal());
                                    }
    void                         invert()
                                    {
                                        T n = normal();
                                        if (n > std::numeric_limits<T>::min())
                                        {
                                            n = 1.0 / n;
                                            conjugate();
                                            vec[0] *= n;
                                            vec[1] *= n;
                                            vec[2] *= n;
                                            vec[3] *= n;
                                        }
                                    }

    UT_QuaternionT<T>            exp() const;
    UT_QuaternionT<T>            ln() const;
    UT_QuaternionT<T>            log() const { return ln(); }
    UT_QuaternionT<T>            pow(T exp) const;

    // Form the quaternion which takes v1 and rotates it to v2. 
    // v1 and v2 are assumed normalized
    void                         updateFromVectors(const UT_Vector3T<T> &v1,
                                                   const UT_Vector3T<T> &v2);

    /// Form the quaternion from the rotation component of an
    /// arbitrary 3x3 matrix.
    void                         updateFromArbitraryMatrix(const UT_Matrix3 &);
    void                         updateFromArbitraryMatrix(const UT_Matrix3D &);

    /// Form the quaternion from a rotation matrix
    /// WARNING: This will produce incorrect results if given
    ///          a non-rotation matrix!  Use updateFromArbitraryMatrix
    ///          if you may have a non-rotation matrix.
    void                         updateFromRotationMatrix(const UT_Matrix3 &);
    void                         updateFromRotationMatrix(const UT_Matrix3D &);

    // Form the quaternion from an angle/axis
    void                         updateFromAngleAxis(T angle, 
                                                     const UT_Vector3T<T> &axis,
                                                     int normalize=1);

    void                         getAngleAxis(T &angle,
                                              UT_Vector3T<T> &axis) const;

    void                         updateFromLogMap(const UT_Vector3T<T> &v);
    void                         getLogMap(UT_Vector3T<T> &v) const;

    // Form the quaternion from euler rotation angles (given in radians)
    void                         updateFromEuler(const UT_Vector3T<T> &rot,
                                                 const UT_XformOrder &order);

    // Given the angular velocity omega, compute our derivative into q_prime
    void                         computeDerivative(const UT_Vector3T<T> &omega,
                                                   UT_QuaternionT<T> &q_prime);

    // Returns the angular velocity required to move from the rotation of
    // this quaternion to the destination quaternion in a given time.
    UT_Vector3T<T>               computeAngVel(const UT_QuaternionT<T> &dest,
                                               T time) const;

    // Integrates this quaternion by the given angular velocity and time
    // step.  There are two appraoches to doing this.  For small
    // angular velocity/timesteps, one can compute the derivative
    // implied by the angular velocity, apply linearly, and renormalize.
    // Alternatively, one can construct the proper quaternion for the given
    // angular velocity and rotate by that.  Which method is controlled
    // by the accurate flag.
    void                         integrate(const UT_Vector3T<T> &angvel, 
                                           T timestep,
                                           bool accurate = true);

    // Returns the rx/ry/rz euler rotation representation of the quaternion.
    // The returned rotations are in radians.
    UT_Vector3T<T>               computeRotations(const UT_XformOrder &) const;

    /// Rotates a vector by this quaternion
    /// Requires that this is normalized.
    SYS_NO_DISCARD_RESULT
    inline UT_Vector3T<T>        rotate(const UT_Vector3T<T> &) const;

    /// rotates a vector by the inverse of this quaternion.
    /// Requires that this is normalized.
    SYS_NO_DISCARD_RESULT
    inline UT_Vector3T<T>        rotateInverse(const UT_Vector3T<T> &) const;

    // Multiply this quarternion's "real world" Euler angles by the given
    // scalar s.  That is, if this quaternion is 
    // [ cos(a), n1 sin(a), n2 sin(a), n3 sin(a) ]  it is replaced by
    // [ cos(a*s), n1 sin(a*s), n2 sin(a*s), n3 sin(a*s) ] 
    void                        multAngle( T s );

    // Decomposes this quaternion into a twist component along the axis and a swing component
    // When reverse is false the decomposition is Q = Swing * Twist
    void                        swingTwistDecompose(
                                    const UT_Vector3T<T> &axis,
                                    UT_QuaternionT<T> &swing,
                                    UT_QuaternionT<T> &twist,
                                    const bool reverse = false) const;

    T                           &x() { return vec[0]; }
    T                           &y() { return vec[1]; }
    T                           &z() { return vec[2]; }
    T                           &w() { return vec[3]; }

    T                           x() const { return vec[0]; }
    T                           y() const { return vec[1]; }
    T                           z() const { return vec[2]; }
    T                           w() const { return vec[3]; }

    void                        save(std::ostream &os, int binary=0) const;
    bool                        load(UT_IStream &is);

    /// @{
    /// Methods to serialize to a JSON stream.  The vector is stored as an
    /// array of 4 reals.
    bool                save(UT_JSONWriter &w) const;
    bool                save(UT_JSONValue &v) const;
    bool                load(UT_JSONParser &p);
    /// @}

    const T     *data() const   { return &vec[0]; }
    T           *data()         { return &vec[0]; }

    T           distance2(const UT_QuaternionT<T> &b) const noexcept
    {
        return UT::FA::Distance2<T, tuple_size>{}(vec, b.vec);
    }
    T           distance(const UT_QuaternionT<T> &b) const noexcept
    {
        return SYSsqrt(distance2(b));
    }

    static int   entries()              { return tuple_size; }

    /// Compute a hash
    unsigned    hash() const    { return SYSvector_hash(data(), tuple_size); }

protected:
    void                         initialize(T qx = 0, T qy = 0, 
                                            T qz = 0, T qw = 0)
                                     {
                                         vec[0] = qx; vec[1] = qy; 
                                         vec[2] = qz; vec[3] = qw;
                                     }
private:
    // I/O friends:
    friend std::ostream &operator<<(std::ostream &os, const UT_QuaternionT<T> &v)
                        {
                            v.save(os);
                            return os;
                        }
    T                   vec[tuple_size];
};

template <typename T>
UT_API size_t format(char *buf, size_t buf_size, const UT_QuaternionT<T> &q);

template <typename T>
inline
UT_QuaternionT<T>::UT_QuaternionT(T angle, const UT_Vector3T<T> &axis,
                             int donormalize)
{
    updateFromAngleAxis(angle, axis, donormalize);
}

template <typename T>
inline bool
UT_QuaternionT<T>::operator==(const UT_QuaternionT<T> &quat) const
{
    return (vec[0] == quat.vec[0] &&
            vec[1] == quat.vec[1] &&
            vec[2] == quat.vec[2] &&
            vec[3] == quat.vec[3]);
}

template <typename T>
inline bool
UT_QuaternionT<T>::operator!=(const UT_QuaternionT<T> &quat) const
{
    return !(*this == quat);
}

template <typename T>
inline bool
UT_QuaternionT<T>::isEqual(const UT_QuaternionT<T> &quat, T tol) const
{
    // Two quaternions are equal if all values are equal, or if all values
    // are equal magnitude but opposite sign. Both sets of values represent
    // the same overall rotation.
    return ((SYSisEqual(vec[0], quat.vec[0], tol) &&
             SYSisEqual(vec[1], quat.vec[1], tol) &&
             SYSisEqual(vec[2], quat.vec[2], tol) &&
             SYSisEqual(vec[3], quat.vec[3], tol)) ||
            (SYSisEqual(-vec[0], quat.vec[0], tol) &&
             SYSisEqual(-vec[1], quat.vec[1], tol) &&
             SYSisEqual(-vec[2], quat.vec[2], tol) &&
             SYSisEqual(-vec[3], quat.vec[3], tol)));
}

template <typename T>
inline UT_QuaternionT<T>
operator*(const UT_QuaternionT<T> &q1, const UT_QuaternionT<T> &q2)
{
    UT_QuaternionT<T>    product = q1;

    product *= q2;

    return UT_QuaternionT<T>(product);
}

template <typename T>
inline UT_QuaternionT<T>
operator+(const UT_QuaternionT<T> &q1, const UT_QuaternionT<T> &q2)
{
    return UT_QuaternionT<T>(q1.x() + q2.x(),
                         q1.y() + q2.y(),
                         q1.z() + q2.z(),
                         q1.w() + q2.w());
}

template <typename T>
inline UT_QuaternionT<T> &
UT_QuaternionT<T>::operator+=(const UT_QuaternionT<T> &quat)
{
    vec[0] += quat.vec[0];
    vec[1] += quat.vec[1];
    vec[2] += quat.vec[2];
    vec[3] += quat.vec[3];

    return *this;
}

template <typename T>
inline UT_QuaternionT<T>
operator-(const UT_QuaternionT<T> &q1, const UT_QuaternionT<T> &q2)
{
    return UT_QuaternionT<T>(q1.x() - q2.x(),
                         q1.y() - q2.y(),
                         q1.z() - q2.z(),
                         q1.w() - q2.w());
}

template <typename T>
inline UT_QuaternionT<T>
operator-(const UT_QuaternionT<T> &q)
{
    return UT_QuaternionT<T>(-q.x(),
                         -q.y(),
                         -q.z(),
                         -q.w());
}

template <typename T>
inline UT_QuaternionT<T>
operator*(const UT_QuaternionT<T> &q, T scalar)
{
    return UT_QuaternionT<T>(q.x() * scalar,
                         q.y() * scalar,
                         q.z() * scalar,
                         q.w() * scalar);
}

template <typename T>
inline UT_QuaternionT<T>
operator*(T scalar, const UT_QuaternionT<T> &q)
{
    return UT_QuaternionT<T>(q.x() * scalar,
                         q.y() * scalar,
                         q.z() * scalar,
                         q.w() * scalar);
}

template <typename T>
inline UT_QuaternionT<T> &
UT_QuaternionT<T>::operator*=(const UT_QuaternionT<T> &q)
{
    UT_Vector3T<T>       v1(vec[0], vec[1], vec[2]);
    UT_Vector3T<T>       v2(q.vec[0], q.vec[1], q.vec[2]);
    UT_Vector3T<T>       v3;
    T                    s1 = vec[3], s2 = q.vec[3];

    vec[3] = s1*s2 - v1.dot(v2);
    v3 = s1*v2 + s2*v1 + cross(v1, v2);
    vec[0] = v3[0];
    vec[1] = v3[1];
    vec[2] = v3[2];

    return *this;
}

template <typename T>
inline UT_QuaternionT<T> &
UT_QuaternionT<T>::operator*=(T scalar)
{
    vec[0] *= scalar;
    vec[1] *= scalar;
    vec[2] *= scalar;
    vec[3] *= scalar;

    return *this;
}

template <typename T>
inline UT_QuaternionT<T>
operator/(const UT_QuaternionT<T> &a, const UT_QuaternionT<T> &b)
{
    UT_QuaternionT<T>   a1 = a;
    UT_QuaternionT<T>   b1 = b;

    b1.invert();
    a1 *= b1;

    return UT_QuaternionT<T>(a1);
}

template <typename T>
inline UT_QuaternionT<T>
operator/(const UT_QuaternionT<T> &q, T scalar)
{
    T d = 1.0/scalar;
    return UT_QuaternionT<T>(q.x()*d, q.y()*d, q.z()*d, q.w()*d);
}

template <typename T>
inline UT_QuaternionT<T> &
UT_QuaternionT<T>::operator/=(const UT_QuaternionT<T> &quat)
{
    UT_QuaternionT<T> q = quat;

    q.invert();
    operator*=(q);

    return *this;
}

template <typename T>
inline UT_QuaternionT<T> &
UT_QuaternionT<T>::operator/=(T scalar)
{
    T d = 1.0F/scalar;

    vec[0] *= d;
    vec[1] *= d;
    vec[2] *= d;
    vec[3] *= d;

    return *this;
}

template <typename T>
inline UT_Vector3T<T>
UT_QuaternionT<T>::rotate(const UT_Vector3T<T> &v) const
{
    UT_QuaternionT<T> q = (*this) *
                      UT_QuaternionT<T>(v.x(), v.y(), v.z(), 0.0f) * 
                      UT_QuaternionT<T>(-vec[0], -vec[1], -vec[2], vec[3]);
    return UT_Vector3T<T>(q.x(), q.y(), q.z());
}

template <typename T>
inline UT_Vector3T<T>
UT_QuaternionT<T>::rotateInverse(const UT_Vector3T<T> &v) const
{
    UT_QuaternionT<T> q = UT_QuaternionT<T>(-vec[0], -vec[1], -vec[2], vec[3]) *
                      UT_QuaternionT<T>(v.x(), v.y(), v.z(), 0.0f) * 
                      (*this);
    return UT_Vector3T<T>(q.x(), q.y(), q.z());
}

template <typename T>
inline T
dot( const UT_QuaternionT<T> &q1, const UT_QuaternionT<T> &q2 )
{
    return q1.x()*q2.x() + q1.y()*q2.y() + q1.z()*q2.z() + q1.w()*q2.w();
}

template <typename T>
inline size_t
hash_value(const UT_QuaternionT<T> &val)
{
    return val.hash();
}

typedef UT_QuaternionT<fpreal32>        UT_Quaternion;
typedef UT_QuaternionT<fpreal>          UT_QuaternionR;
typedef UT_QuaternionT<fpreal16>        UT_QuaternionH;
typedef UT_QuaternionT<fpreal32>        UT_QuaternionF;
typedef UT_QuaternionT<fpreal64>        UT_QuaternionD;

template< typename T, exint D >
class UT_FixedVector;

template<typename T>
struct UT_FixedVectorTraits<UT_QuaternionT<T> >
{
    typedef UT_FixedVector<T,4> FixedVectorType;
    typedef T DataType;
    static const exint TupleSize = 4;
    static const bool isVectorType = true;
};

// UT_QuaternionTFromFixed<T> is a function object that
// creates a UT_QuaternionT<T> from a fixed array-like type TS,
// examples of which include T[4], UT_FixedVector<T,4> and UT_FixedArray<T,4> (AKA std::array<T,4>)
template <typename T>
struct UT_QuaternionTFromFixed
{    
    template< typename TS >
    constexpr SYS_FORCE_INLINE UT_QuaternionT<T> operator()(const TS& as) const noexcept
    {                
        SYS_STATIC_ASSERT( SYS_IsFixedArrayOf_v< TS, T, 4 > );

        return UT_QuaternionT<T>{as[0], as[1], as[2], as[3]};
    }
};

// Convert a fixed array-like type TS into a UT_QuaternionT< T >.
// This allows conversion to UT_QuaternionT without fixing T.
// Instead, the element type of TS determines the type T.
template< typename TS >
constexpr UT_QuaternionT< SYS_FixedArrayElement_t< TS > >
UTmakeQuaternionT( const TS& as ) noexcept
{
    using T = SYS_FixedArrayElement_t< TS >;

    return UT_QuaternionTFromFixed< T >{}( as );
} 

// UT_FromFixed<V> creates a V from a flat, fixed array-like representation

// Primary
template <typename V >
struct UT_FromFixed;

// Partial specialization for UT_QuaternionT
template <typename T>
struct UT_FromFixed< UT_QuaternionT<T> > : UT_QuaternionTFromFixed<T> {};

///////////////////////////////////////////////////////////////////////////////
//
// Implementations
//

template <typename T>
inline UT_QuaternionT<T>
SYSlerp(const UT_QuaternionT<T> &q1, const UT_QuaternionT<T> &q2, T t)
{
    return UT_QuaternionT<T>( SYSlerp(q1.x(), q2.x(), t)
                            , SYSlerp(q1.y(), q2.y(), t)
                            , SYSlerp(q1.z(), q2.z(), t)
                            , SYSlerp(q1.w(), q2.w(), t)
                            );
}

#endif