File content as of revision 1:e25ff4b06ed2:

/*
    File:           Vec2.h

    Function:       Defines a length-2 vector.

    Author(s):      Andrew Willmott

    Copyright:      (c) 1995-2001, Andrew Willmott
 */

#ifndef __Vec2__
#define __Vec2__
#include "Constants.h"
#include "Basics.h"

// --- Vec2 Class -------------------------------------------------------------


class Vec2
{
public:

    // Constructors

                Vec2();
                Vec2(double x, double y);       // (x, y)
                Vec2(const Vec2 &v);        // Copy constructor
                Vec2(ZeroOrOne k);          // v[i] = vl_zero
                Vec2(Axis k);               // v[k] = 1

    // Accessor functions

    double        &operator [] (Int i);
    const double  &operator [] (Int i) const;

    Int         Elts() const { return(2); };
    double        *Ref() const;                       // Return ptr to data

    // Assignment operators

    Vec2        &operator =  (const Vec2 &a);
    Vec2        &operator =  (ZeroOrOne k);
    Vec2        &operator =  (Axis k);

    Vec2        &operator += (const Vec2 &a);
    Vec2        &operator -= (const Vec2 &a);
    Vec2        &operator *= (const Vec2 &a);
    Vec2        &operator *= (double s);
    Vec2        &operator /= (const Vec2 &a);
    Vec2        &operator /= (double s);

    // Comparison operators

    bool        operator == (const Vec2 &a) const;  // v == a?
    bool        operator != (const Vec2 &a) const;  // v != a?

    // Arithmetic operators

    Vec2        operator + (const Vec2 &a) const;   // v + a
    Vec2        operator - (const Vec2 &a) const;   // v - a
    Vec2        operator - () const;                // -v
    Vec2        operator * (const Vec2 &a) const;   // v * a (vx * ax, ...)
    Vec2        operator * (double s) const;          // v * s
    Vec2        operator / (const Vec2 &a) const;   // v / a (vx / ax, ...)
    Vec2        operator / (double s) const;          // v / s

    // Initialisers

    Vec2        &MakeZero();                        // Zero vector
    Vec2        &MakeUnit(Int i, double k = vl_one);  // I[i]
    Vec2        &MakeBlock(double k = vl_one);        // All-k vector

    Vec2        &Normalise();                       // normalise vector

    // Private...

protected:

    double            elt[2];
};


// --- Vec operators ----------------------------------------------------------

inline Vec2     operator * (double s, const Vec2 &v); // s * v
inline double     dot(const Vec2 &a, const Vec2 &b);  // v . a
inline double     len(const Vec2 &v);                 // || v ||
inline double     sqrlen(const Vec2 &v);              // v . v
inline Vec2     norm(const Vec2 &v);                // v / || v ||
inline void     normalise(Vec2 &v);                 // v = norm(v)
inline Vec2     cross(const Vec2 &v);               // cross prod.

//std::ostream &operator << (std::ostream &s, const Vec2 &v);
//std::istream &operator >> (std::istream &s, Vec2 &v);

inline void printVec2(const Vec2 &v);


// --- Inlines ----------------------------------------------------------------

inline double &Vec2::operator [] (Int i)
{
    CheckRange(i, 0, 2, "(Vec2::[i]) index out of range");
    return(elt[i]);
}

inline const double &Vec2::operator [] (Int i) const
{
    CheckRange(i, 0, 2, "(Vec2::[i]) index out of range");
    return(elt[i]);
}

inline Vec2::Vec2()
{
}

inline Vec2::Vec2(double x, double y)
{
    elt[0] = x;
    elt[1] = y;
}

inline Vec2::Vec2(const Vec2 &v)
{
    elt[0] = v[0];
    elt[1] = v[1];
}

inline double *Vec2::Ref() const
{
    return((double *) elt);
}

inline Vec2 &Vec2::operator = (const Vec2 &v)
{
    elt[0] = v[0];
    elt[1] = v[1];

    return(SELF);
}

inline Vec2 &Vec2::operator += (const Vec2 &v)
{
    elt[0] += v[0];
    elt[1] += v[1];

    return(SELF);
}

inline Vec2 &Vec2::operator -= (const Vec2 &v)
{
    elt[0] -= v[0];
    elt[1] -= v[1];

    return(SELF);
}

inline Vec2 &Vec2::operator *= (const Vec2 &v)
{
    elt[0] *= v[0];
    elt[1] *= v[1];

    return(SELF);
}

inline Vec2 &Vec2::operator *= (double s)
{
    elt[0] *= s;
    elt[1] *= s;

    return(SELF);
}

inline Vec2 &Vec2::operator /= (const Vec2 &v)
{
    elt[0] /= v[0];
    elt[1] /= v[1];

    return(SELF);
}

inline Vec2 &Vec2::operator /= (double s)
{
    elt[0] /= s;
    elt[1] /= s;

    return(SELF);
}

inline Vec2 Vec2::operator + (const Vec2 &a) const
{
    Vec2 result;

    result[0] = elt[0] + a[0];
    result[1] = elt[1] + a[1];

    return(result);
}

inline Vec2 Vec2::operator - (const Vec2 &a) const
{
    Vec2 result;

    result[0] = elt[0] - a[0];
    result[1] = elt[1] - a[1];

    return(result);
}

inline Vec2 Vec2::operator - () const
{
    Vec2 result;

    result[0] = -elt[0];
    result[1] = -elt[1];

    return(result);
}

inline Vec2 Vec2::operator * (const Vec2 &a) const
{
    Vec2 result;

    result[0] = elt[0] * a[0];
    result[1] = elt[1] * a[1];

    return(result);
}

inline Vec2 Vec2::operator * (double s) const
{
    Vec2 result;

    result[0] = elt[0] * s;
    result[1] = elt[1] * s;

    return(result);
}

inline Vec2 operator * (double s, const Vec2 &v)
{
    return(v * s);
}

inline Vec2 Vec2::operator / (const Vec2 &a) const
{
    Vec2 result;

    result[0] = elt[0] / a[0];
    result[1] = elt[1] / a[1];

    return(result);
}

inline Vec2 Vec2::operator / (double s) const
{
    Vec2 result;

    result[0] = elt[0] / s;
    result[1] = elt[1] / s;

    return(result);
}

inline double dot(const Vec2 &a, const Vec2 &b)
{
    return(a[0] * b[0] + a[1] * b[1]);
}

inline Vec2 cross(const Vec2 &a)
{
    Vec2 result;

    result[0] =  a[1];
    result[1] = -a[0];

    return(result);
}

inline double len(const Vec2 &v)
{
    return(sqrt(dot(v, v)));
}

inline double sqrlen(const Vec2 &v)
{
    return(dot(v, v));
}

inline Vec2 norm(const Vec2 &v)
{
    Assert(sqrlen(v) > 0.0, "normalising length-zero vector");
    return(v / len(v));
}

inline void normalise(Vec2 &v)
{
    v /= len(v);
}

inline Vec2 &Vec2::MakeUnit(Int i, double k)
{
    if (i == 0)
    { elt[0] = k; elt[1] = vl_zero; }
    else if (i == 1)
    { elt[0] = vl_zero; elt[1] = k; }
    else
        _Error("(Vec2::Unit) illegal unit vector");
    return(SELF);
}

inline Vec2 &Vec2::MakeZero()
{
    elt[0] = vl_zero; elt[1] = vl_zero;
    return(SELF);
}

inline Vec2 &Vec2::MakeBlock(double k)
{
    elt[0] = k; elt[1] = k;
    return(SELF);
}

inline Vec2 &Vec2::Normalise()
{
    Assert(sqrlen(SELF) > 0.0, "normalising length-zero vector");
    SELF /= len(SELF);
    return(SELF);
}


inline Vec2::Vec2(ZeroOrOne k)
{
    elt[0] = k;
    elt[1] = k;
}

inline Vec2::Vec2(Axis k)
{
    MakeUnit(k, vl_one);
}

inline Vec2 &Vec2::operator = (ZeroOrOne k)
{
    elt[0] = k; elt[1] = k;

    return(SELF);
}

inline Vec2 &Vec2::operator = (Axis k)
{
    MakeUnit(k, vl_1);

    return(SELF);
}

inline bool Vec2::operator == (const Vec2 &a) const
{
    return(elt[0] == a[0] && elt[1] == a[1]);
}

inline bool Vec2::operator != (const Vec2 &a) const
{
    return(elt[0] != a[0] || elt[1] != a[1]);
}

inline void printVec2(const Vec2 &v)
{    
    printf("[%10f %10f]",v[0],v[1]);
}


#endif