/***********************************************************
* vector.h - a vector class written in c++                 *
* functions for +, -, dotproduct, crossproduct, scaling,   *
* length & normalizing, many of these are operators        *
* By Tomas Moller                                          *
***********************************************************/
#ifndef VECTOR_H
#define VECTOR_H

#include <iostream>
#include <string.h>
#include <math.h>

#define Xi 0			// indices into vector
#define Yi 1
#define Zi 2

class Vector
{
	protected:
		float fx,fy,fz;
	public:
		Vector() {fx=0.f;fy=0.f;fz=0.f;}		// constructor with no argument
		Vector(float x,float y,float z);			// constructor with coords
		Vector(Vector& a);						// constructor with vector
		void Set(float x,float y,float z);			// assign new values to vector
		void SetX(float x);						// set x
		void SetY(float y);						// set y
		void SetZ(float z);						// set z;
		void SetIndex(int index,float value);	// set x,y or z to value depending on index
		float X(void);							// return fx
		float Y(void);							// return fy
		float Z(void);							// return fz
		void Add(float x,float y,float z);			// addition to this vector
		void Sub(float x,float y,float z);			// subtraction
		void Scale(float a);						// scaling of vector
		float Length(void);						// length of vector
		void Normalize(void);					// normalize vector

		void operator=(const Vector& a);				// operator: assignment
		Vector operator*(float t);				// operator: scaling
		Vector operator+(const Vector& a);			// operator: addition
		Vector operator-(const Vector& a);			// operator: subtraction
		Vector operator+(void);					// unary +
		Vector operator-(void);					// unary -
		void operator+=(const Vector& a);				// operator: +=
		void operator-=(const Vector& a);				// operator: -=
		void operator*=(float t);				// operator: *= (scaling)
		float operator*(const Vector& a);				// operator: dot product
		Vector operator%(const Vector& a);			// operator: cross product
		float operator[](short index);			// if short=0 then X, short=1 then Y, else Z, see constants above
		void print(void);						// print coords

};

/* here follows the inline functions and operators */

inline Vector::Vector(float x,float y,float z)
{ fx=x; fy=y; fz=z; }

inline Vector::Vector(Vector& a)
{ fx=a.fx; fy=a.fy; fz=a.fz; }

inline void Vector::Set(float x,float y,float z)
{ fx=x; fy=y; fz=z; }

inline void Vector::SetX(float x)
{ fx=x;}

inline void Vector::SetY(float y)
{ fy=y; }

inline void Vector::SetZ(float z)
{ fz=z; }

inline void Vector::SetIndex(int index,float value)
{
	switch(index)
	{
		case Xi: fx=value;
		case Yi: fy=value;
		case Zi: fz=value;
	}
}

inline float Vector::X(void)
{ return fx; }

inline float Vector::Y(void)
{ return fy; }

inline float Vector::Z(void)
{ return fz; }

inline void Vector::Add(float x,float y,float z)
{ fx+=x; fy+=y; fz+=z; }
 
inline void Vector::Sub(float x,float y,float z)
{ fx-=x; fy-=y; fz-=z; }

inline void Vector::Scale(float a)
{ fx*=a; fy*=a; fz*=a; }

inline float Vector::Length(void)
{ return sqrt((*this)*(*this));	// square root of Dot(this,this)
}

inline void Vector::Normalize(void)
{ 
	if(Length()==0.f) std::cout<<"Error:normalize\n";
 	else Scale(1.f/Length());
}

/****************** Operators *********************/
inline void Vector::operator=(const Vector& a)	// assignment
{ fx=a.fx; fy=a.fy; fz=a.fz; }

inline Vector Vector::operator+(void)		// unary +
{ return *this; }

inline Vector Vector::operator*(float t)		// scaling
{ Vector temp; temp.Set(fx*t,fy*t,fz*t); return temp; }

inline Vector Vector::operator+(const Vector& a)
{ Vector sum; sum.Set(fx+a.fx,fy+a.fy,fz+a.fz); return sum; }

inline Vector Vector::operator-(const Vector& a)
{ Vector sum; sum.Set(fx-a.fx,fy-a.fy,fz-a.fz); return sum; }

inline Vector Vector::operator-(void)			// unary -
{ Vector neg; neg.Set(-fx,-fy,-fz); return neg; }

inline void Vector::operator+=(const Vector& a)
{ Set(fx+a.fx,fy+a.fy,fz+a.fz); }

inline void Vector::operator-=(const Vector& a)
{ Set(fx-a.fx,fy-a.fy,fz-a.fz); }

inline void Vector::operator*=(float t)		// scaling
{ Set(fx*t,fy*t,fz*t); }

inline float Vector::operator*(const Vector& a)		// dot product
{ return fx*a.fx+fy*a.fy+fz*a.fz; }

inline Vector Vector::operator%(const Vector& a)		// cross product
{
	Vector cross;
	cross.Set(fy*a.fz-fz*a.fy,fz*a.fx-fx*a.fz,fx*a.fy-fy*a.fx);
	return cross;
}

inline float Vector::operator[](short index)
{
	switch(index)
	{
		case Xi: return fx;
		case Yi: return fy;
		case Zi: return fz;
	}
	return 0.f;					// if invalid index
}
/*************** End of Operators *****************/

inline void Vector::print(void)
{
	//std::cout<<form("x:%.6f y:%.6f z:%.6f\n",fx,fy,fz);
}
#endif