239 lines
6.8 KiB
Plaintext
239 lines
6.8 KiB
Plaintext
#ifndef OSG_QUAT
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#define OSG_QUAT 1
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#include <osg/Vec3>
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#include <osg/Vec4>
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#include <osg/Matrix>
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namespace osg {
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/** A quaternion class. It can be used to represent an orientation in 3D space.*/
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class SG_EXPORT Quat
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{
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public:
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/* ----------------------------------------------------------
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DATA MEMBERS
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The only data member is a
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Vec4 which holds the elements
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In other words, osg:Quat is composed of an osg::Vec4
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The osg::Quat aggregates an osg::Vec4
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These seem to be different jargon for the same thing :-)
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---------------------------------------------------------- */
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Vec4 _fv; // a four-vector
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Quat() {}
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Quat( float x, float y, float z, float w ): _fv(x,y,z,w) {}
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Quat( const Vec4& v ): _fv(v) {}
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/* ----------------------------------
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Methods to access data members
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---------------------------------- */
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inline Vec4& asVec4()
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{
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return _fv;
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}
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inline const Vec4& asVec4() const
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{
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return _fv;
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}
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inline const Vec3 asVec3() const
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{
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return Vec3(_fv[0], _fv[1], _fv[2]);
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}
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inline void set(const float x, const float y, const float z, const float w)
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{
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_fv.set(x,y,z,w);
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}
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inline void set(const osg::Vec4& v)
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{
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_fv = v;
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}
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/* -------------------------------------------------------------
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BASIC ARITHMETIC METHODS
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Implemented in terms of Vec4s. Some Vec4 operators, e.g.
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operator* are not appropriate for quaternions (as
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mathematical objects) so they are implemented differently.
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Also define methods for conjugate and the multiplicative inverse.
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------------------------------------------------------------- */
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/// Multiply by scalar
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inline const Quat operator * (const float& rhs) const
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{
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return Quat(_fv*rhs);
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}
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/// Unary multiply by scalar
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inline Quat& operator *= (const float& rhs)
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{
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_fv*=rhs;
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return *this; // enable nesting
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}
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/// Binary multiply
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inline const Quat operator*(const Quat& rhs) const
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{
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return Quat( _fv[3]*rhs._fv[0] + _fv[0]*rhs._fv[3] + _fv[1]*rhs._fv[2] - _fv[2]*rhs._fv[1],
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_fv[3]*rhs._fv[1] - _fv[0]*rhs._fv[2] + _fv[1]*rhs._fv[3] + _fv[2]*rhs._fv[0],
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_fv[3]*rhs._fv[2] + _fv[0]*rhs._fv[1] - _fv[1]*rhs._fv[0] + _fv[2]*rhs._fv[3],
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_fv[3]*rhs._fv[3] - _fv[0]*rhs._fv[0] - _fv[1]*rhs._fv[1] - _fv[2]*rhs._fv[2] );
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}
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/// Unary multiply
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inline Quat& operator*=(const Quat& rhs)
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{
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float x = _fv[3]*rhs._fv[0] + _fv[0]*rhs._fv[3] + _fv[1]*rhs._fv[2] - _fv[2]*rhs._fv[1];
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float y = _fv[3]*rhs._fv[1] - _fv[0]*rhs._fv[2] + _fv[1]*rhs._fv[3] + _fv[2]*rhs._fv[0];
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float z = _fv[3]*rhs._fv[2] + _fv[0]*rhs._fv[1] - _fv[1]*rhs._fv[0] + _fv[2]*rhs._fv[3];
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_fv[3] = _fv[3]*rhs._fv[3] - _fv[0]*rhs._fv[0] - _fv[1]*rhs._fv[1] - _fv[2]*rhs._fv[2];
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_fv[2] = z;
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_fv[1] = y;
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_fv[0] = x;
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return (*this); // enable nesting
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}
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/// Divide by scalar
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inline const Quat operator / (const float& rhs) const
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{
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return Quat(_fv/rhs);
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}
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/// Unary divide by scalar
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inline Quat& operator /= (const float& rhs)
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{
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_fv/=rhs;
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return *this;
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}
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/// Binary divide
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inline const Quat operator/(const Quat& denom) const
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{
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return ( (*this) * denom.inverse() );
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}
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/// Unary divide
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inline Quat& operator/=(const Quat& denom)
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{
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(*this) = (*this) * denom.inverse();
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return (*this); // enable nesting
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}
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/// Binary addition
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inline const Quat operator + (const Quat& rhs) const
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{
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return Quat( _fv + rhs._fv );
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}
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/// Unary addition
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inline Quat& operator += (const Quat& rhs)
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{
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_fv += rhs._fv;
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return *this; // enable nesting
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}
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/// Binary subtraction
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inline const Quat operator - (const Quat& rhs) const
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{
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return Quat( _fv - rhs._fv );
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}
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/// Unary subtraction
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inline Quat& operator -= (const Quat& rhs)
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{
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_fv-=rhs._fv;
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return *this; // enable nesting
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}
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/** Negation operator - returns the negative of the quaternion.
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Basically just calls operator - () on the Vec4 */
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inline const Quat operator - () const
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{
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return Quat ( -_fv );
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}
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/// Length of the quaternion = sqrt( vec . vec )
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const float length() const
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{
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return _fv.length();
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}
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/// Length of the quaternion = vec . vec
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const float length2() const
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{
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return _fv.length2();
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}
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/// Conjugate
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inline const Quat conj () const
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{
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return Quat( -_fv[0], -_fv[1], -_fv[2], _fv[3] );
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}
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/// Multiplicative inverse method: q^(-1) = q^*/(q.q^*)
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inline const Quat inverse () const
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{
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return conj() / length2();
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}
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/* --------------------------------------------------------
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METHODS RELATED TO ROTATIONS
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Set a quaternion which will perform a rotation of an
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angle around the axis given by the vector (x,y,z).
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Should be written to also accept an angle and a Vec3?
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Define Spherical Linear interpolation method also
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Not inlined - see the Quat.cpp file for implementation
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-------------------------------------------------------- */
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void makeRot ( const float angle,
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const float x, const float y, const float z );
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void makeRot ( const float angle, const Vec3& vec );
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/** Make a rotation Quat which will rotate vec1 to vec2.
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Generally take adot product to get the angle between these
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and then use a cross product to get the rotation axis
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Watch out for the two special cases of when the vectors
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are co-incident or opposite in direction.*/
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void makeRot( const Vec3& vec1, const Vec3& vec2 );
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/** Return the angle and vector components represented by the quaternion.*/
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void getRot ( float& angle, float& x, float& y, float& z ) const;
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/** Return the angle and vector represented by the quaternion.*/
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void getRot ( float& angle, Vec3& vec ) const;
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/** Spherical Linear Interpolation.
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As t goes from 0 to 1, the Quat object goes from "from" to "to". */
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void slerp ( const float t, const Quat& from, const Quat& to);
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/** Set quaternion to be equivalent to specified matrix.*/
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void set( const osg::Matrix& m );
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/** Get the equivalent matrix for this quaternion.*/
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void get( osg::Matrix& m ) const;
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friend inline ostream& operator << (ostream& output, const Quat& vec);
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}; // end of class prototype
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inline ostream& operator << (ostream& output, const Quat& vec)
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{
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output << vec._fv[0] << " "
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<< vec._fv[1] << " "
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<< vec._fv[2] << " "
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<< vec._fv[3];
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return output; // to enable cascading
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}
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}; // end of namespace
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#endif
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