/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
 *
 * This library is open source and may be redistributed and/or modified under  
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSG_VEC2F
#define OSG_VEC2F 1

#include <osg/Math>

namespace osg {

/** General purpose float pair. Uses include representation of
  * texture coordinates.
  * No support yet added for float * Vec2f - is it necessary?
  * Need to define a non-member non-friend operator* etc.
  * BTW: Vec2f * float is okay
*/

class Vec2f
{
    public:

        /** Data type of vector components.*/
        typedef float value_type;

        /** Number of vector components. */
        enum { num_components = 2 };
        
        /** Vec member variable. */
        value_type _v[2];
        

        /** Constructor that sets all components of the vector to zero */
        Vec2f() {_v[0]=0.0; _v[1]=0.0;}
        Vec2f(value_type x,value_type y) { _v[0]=x; _v[1]=y; }


        inline bool operator == (const Vec2f& v) const { return _v[0]==v._v[0] && _v[1]==v._v[1]; }

        inline bool operator != (const Vec2f& v) const { return _v[0]!=v._v[0] || _v[1]!=v._v[1]; }

        inline bool operator <  (const Vec2f& v) const
        {
            if (_v[0]<v._v[0]) return true;
            else if (_v[0]>v._v[0]) return false;
            else return (_v[1]<v._v[1]);
        }

        inline value_type * ptr() { return _v; }
        inline const value_type * ptr() const { return _v; }

        inline void set( value_type x, value_type y ) { _v[0]=x; _v[1]=y; }

        inline value_type & operator [] (int i) { return _v[i]; }
        inline value_type operator [] (int i) const { return _v[i]; }

        inline value_type & x() { return _v[0]; }
        inline value_type & y() { return _v[1]; }

        inline value_type x() const { return _v[0]; }
        inline value_type y() const { return _v[1]; }

        /** Returns true if all components have values that are not NaN. */
        inline bool valid() const { return !isNaN(); }
        /** Returns true if at least one component has value NaN. */
        inline bool isNaN() const { return osg::isNaN(_v[0]) || osg::isNaN(_v[1]); }

        /** Dot product. */
        inline value_type operator * (const Vec2f& rhs) const
        {
            return _v[0]*rhs._v[0]+_v[1]*rhs._v[1];
        }

        /** Multiply by scalar. */
        inline const Vec2f operator * (value_type rhs) const
        {
            return Vec2f(_v[0]*rhs, _v[1]*rhs);
        }

        /** Unary multiply by scalar. */
        inline Vec2f& operator *= (value_type rhs)
        {
            _v[0]*=rhs;
            _v[1]*=rhs;
            return *this;
        }

        /** Divide by scalar. */
        inline const Vec2f operator / (value_type rhs) const
        {
            return Vec2f(_v[0]/rhs, _v[1]/rhs);
        }

        /** Unary divide by scalar. */
        inline Vec2f& operator /= (value_type rhs)
        {
            _v[0]/=rhs;
            _v[1]/=rhs;
            return *this;
        }

        /** Binary vector add. */
        inline const Vec2f operator + (const Vec2f& rhs) const
        {
            return Vec2f(_v[0]+rhs._v[0], _v[1]+rhs._v[1]);
        }

        /** Unary vector add. Slightly more efficient because no temporary
          * intermediate object.
        */
        inline Vec2f& operator += (const Vec2f& rhs)
        {
            _v[0] += rhs._v[0];
            _v[1] += rhs._v[1];
            return *this;
        }

        /** Binary vector subtract. */
        inline const Vec2f operator - (const Vec2f& rhs) const
        {
            return Vec2f(_v[0]-rhs._v[0], _v[1]-rhs._v[1]);
        }

        /** Unary vector subtract. */
        inline Vec2f& operator -= (const Vec2f& rhs)
        {
            _v[0]-=rhs._v[0];
            _v[1]-=rhs._v[1];
            return *this;
        }

        /** Negation operator. Returns the negative of the Vec2f. */
        inline const Vec2f operator - () const
        {
            return Vec2f (-_v[0], -_v[1]);
        }

        /** Length of the vector = sqrt( vec . vec ) */
        inline value_type length() const
        {
            return sqrtf( _v[0]*_v[0] + _v[1]*_v[1] );
        }

        /** Length squared of the vector = vec . vec */
        inline value_type length2( void ) const
        {
            return _v[0]*_v[0] + _v[1]*_v[1];
        }

        /** Normalize the vector so that it has length unity.
          * Returns the previous length of the vector.
        */
        inline value_type normalize()
        {
            value_type norm = Vec2f::length();
            if (norm>0.0)
            {
                value_type inv = 1.0f/norm;
                _v[0] *= inv;
                _v[1] *= inv;
            }
            return( norm );
        }
        
};    // end of class Vec2f

/** multiply by vector components. */
inline Vec2f componentMultiply(const Vec2f& lhs, const Vec2f& rhs)
{
    return Vec2f(lhs[0]*rhs[0], lhs[1]*rhs[1]);
}

/** divide rhs components by rhs vector components. */
inline Vec2f componentDivide(const Vec2f& lhs, const Vec2f& rhs)
{
    return Vec2f(lhs[0]/rhs[0], lhs[1]/rhs[1]);
}

}    // end of namespace osg
#endif