Vector2.h

Go to the documentation of this file.

/*

License

Menge
Copyright © and trademark ™ 2012-14 University of North Carolina at Chapel Hill. 
All rights reserved.

Permission to use, copy, modify, and distribute this software and its documentation 
for educational, research, and non-profit purposes, without fee, and without a 
written agreement is hereby granted, provided that the above copyright notice, 
this paragraph, and the following four paragraphs appear in all copies.

This software program and documentation are copyrighted by the University of North 
Carolina at Chapel Hill. The software program and documentation are supplied "as is," 
without any accompanying services from the University of North Carolina at Chapel 
Hill or the authors. The University of North Carolina at Chapel Hill and the 
authors do not warrant that the operation of the program will be uninterrupted 
or error-free. The end-user understands that the program was developed for research 
purposes and is advised not to rely exclusively on the program for any reason.

IN NO EVENT SHALL THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE AUTHORS 
BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL 
DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS 
DOCUMENTATION, EVEN IF THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE 
AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS SPECIFICALLY 
DISCLAIM ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND ANY STATUTORY WARRANTY 
OF NON-INFRINGEMENT. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND 
THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS HAVE NO OBLIGATIONS 
TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

Any questions or comments should be sent to the authors {menge,geom}@cs.unc.edu

*/

#ifndef __VECTOR2_H__
#define __VECTOR2_H__

#include "CoreConfig.h"
#include <cmath>
#include <ostream>
#include "Logger.h"
#include "Math/consts.h"

#ifdef _MSC_VER
    // To export templated classes and functions, requires declaring specializations
    // extern.  This became standard in C++11, but prior to that it is considered a
    //  "microsoft extension".  This silences the warnings.
    #pragma warning( disable : 4231 )
#endif

namespace Menge {

    namespace Math {
        inline MENGE_API float sqr(float a) {
            return a * a;
        }

        template <class Type> 
        class MENGE_API Vector2d {
        public:

            inline Vector2d() {}

            inline Vector2d( Type x, Type y ): _x(x), _y(y) {}

            inline Vector2d( const Vector2d & v ): _x(v._x), _y(v._y) {}


            inline Type x() const { return _x; }

            inline Type y() const { return _y; }

            inline void set( Type x, Type y ) {
                _x = x;
                _y = y;
            }

            inline void set( const Vector2d & v ) {
                _x = v._x;
                _y = v._y;
            }

            inline void setX( Type x ) {
                _x = x;
            }

            inline void setY( Type y ) {
                _y = y;
            }

            inline void zero() {
                _x = _y = (Type)0;
            }


            inline Vector2d<Type> operator-() const {
                return Vector2d<Type>( -_x, -_y );
            }

            inline float operator*(const Vector2d& v) const {
                return _x * v._x + _y * v._y;
            }

            inline Vector2d<Type> operator*( float s ) const {
                return Vector2d<Type>( _x * s, _y * s );
            }

            inline Vector2d<Type> operator/( float s ) const {
                const float invS = 1.f / s;
                return Vector2d<Type>( _x * invS, _y * invS );
            }

            inline Vector2d operator+( const Vector2d & v ) const {
              return Vector2d<Type>( _x + v._x, _y + v._y );
            }

            inline Vector2d operator-( const Vector2d & v ) const {
              return Vector2d<Type>( _x - v._x, _y - v._y );
            }

            inline bool operator==( const Vector2d & v ) const {
              return _x == v._x && _y == v._y;
            }

            inline bool operator!=( const Vector2d & v ) const {
              return _x != v._x || _y != v._y;
            }


            inline Vector2d & operator*=( float s ) {
                _x *= s;
                _y *= s;
                return *this;
            }

            inline Vector2d & operator/=( float s ) {
                const float invS = 1.f / s;
                _x *= invS;
                _y *= invS;
                return *this;
            }

            inline Vector2d & operator+=( const Vector2d & v ) {
                _x += v._x;
                _y += v._y;
                return *this;
            }

            inline Vector2d & operator-=( const Vector2d & v ) {
                _x -= v._x;
                _y -= v._y;
                return *this;
            }

            inline void negate() {
                _x = -_x;
                _y = -_y;
            }

            inline void normalize() {
                float len = sqrtf( _x * _x + _y * _y );
                if ( len > EPS ) {
                    _x /= len;
                    _y /= len;
                } else {
                    _x = _y = 0.f;
                }
            }


            inline Type Length() const {
                return sqrt( _x * _x + _y * _y );
            }

            inline float distance( const Vector2d & p ) const {
                float dx = _x - p._x;
                float dy = _y - p._y;
                return sqrtf( dx * dx + dy * dy );
            }

            inline float distance( float x, float y ) const {
                float dx = _x - x;
                float dy = _y - y;
                return sqrtf( dx * dx + dy * dy );
            }

            inline float distanceSq( const Vector2d & p ) const {
                float dx = _x - p._x;
                float dy = _y - p._y;
                return dx * dx + dy * dy ;
            }

            inline float distanceSq( float x, float y ) const {
                float dx = _x - x;
                float dy = _y - y;
                return dx * dx + dy * dy;
            }
            
            Type    _x;

            Type    _y;
        };

        MATHEXTERN template class MENGE_API Vector2d<float>;

        typedef Vector2d<float>  Vector2;



        template< class Type >
        inline MENGE_API Vector2d<Type> operator*( Type s, const Vector2d<Type>& v) {
            return Vector2d<Type>( s * v._x, s * v._y );
        }

        MATHEXTERN template MENGE_API Vector2d<float> operator*( float s, const Vector2d<float>& v);

        template< class Type >
        inline MENGE_API Logger& operator<<(Logger& logger, const Vector2d<Type>& v ) {
            logger << "(" << v.x() << "," << v.y() << ")";
            return logger;
        }

        template< class Type >
        inline MENGE_API std::ostream& operator<<(std::ostream& os, const Vector2d<Type>& v ) {
            os << "(" << v.x() << "," << v.y() << ")";
            return os;
        }

        MATHEXTERN template MENGE_API Logger& operator<<(Logger& os, const Vector2d<float>& v );

        template< class Type >
        inline MENGE_API Type abs( const Vector2d<Type>& v ) {
            return std::sqrt( v * v );
        }

        MATHEXTERN template MENGE_API float abs( const Vector2d<float>& v );

        template< class Type >
        inline MENGE_API Type absSq( const Vector2d<Type>& v ) {
            return v * v;
        }

        MATHEXTERN template MENGE_API float absSq( const Vector2d<float>& v );

        template< class Type >
        inline MENGE_API Type det( const Vector2d<Type>& v1, const Vector2d<Type>& v2) {
            return v1.x() * v2.y() - v1.y() * v2.x();
        }

        MATHEXTERN template MENGE_API float det( const Vector2d<float>& v1, const Vector2d<float>& v2);

        template< class Type >
        inline MENGE_API Vector2d<Type> norm(const Vector2d<Type>& vector) {
            float mag = abs( vector );
            if ( mag < EPS ) {
                // This may not be the "right" behavior.  I do this because the "normalized" vector has unit
                //  length.  This guarantees that the result is always unit length.  Although it introduces other
                //  issues.
                return Vector2d<Type>(1.f, 0.f);
            } else {
                return vector / mag;
            }
        }

        MATHEXTERN template MENGE_API Vector2d<float> norm(const Vector2d<float>& vector);

        template< class Type >
        inline MENGE_API bool equivalent( const Vector2d<Type> & v1, const Vector2d<Type> & v2, float threshSqd=0.000001f ) {
            return absSq( v1 - v2 ) < threshSqd;
        }

        MATHEXTERN template MENGE_API bool equivalent( const Vector2d<float> & v1, const Vector2d<float> & v2, float threshSqd );

        template< class Type >
        inline MENGE_API Type leftOf(const Vector2d<Type>& a, const Vector2d<Type>& b, const Vector2d<Type>& c) {
            return det(a - c, b - a);
        }

        MATHEXTERN template MENGE_API float leftOf(const Vector2d<float>& a, const Vector2d<float>& b, const Vector2d<float>& c);
    }   // namespace Math
}   // namespace Menge

    #ifdef _MSC_VER
        // To export templated classes and functions, requires declaring specializations
        // extern.  This became standard in C++11, but prior to that it is considered a
        //  "microsoft extension".  This silences the warnings.
        #pragma warning( default : 4231 )
    #endif
#endif  //__VECTOR2_H__