v2math.h

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#ifndef LL_V2MATH_H
#define LL_V2MATH_H

#include "llmath.h"

class LLVector4;
class LLMatrix3;
class LLQuaternion;

//  Llvector2 = |x y z w|

static const U32 LENGTHOFVECTOR2 = 2;

class LLVector2
{
        public:
                F32 mV[LENGTHOFVECTOR2];

                static LLVector2 zero;

                LLVector2();                                                    // Initializes LLVector2 to (0, 0)
                LLVector2(F32 x, F32 y);                            // Initializes LLVector2 to (x. y)
                LLVector2(const F32 *vec);                              // Initializes LLVector2 to (vec[0]. vec[1])
                
                // Clears LLVector2 to (0, 0).  DEPRECATED - prefer zeroVec.
                void    clearVec();

                // Zero LLVector2 to (0, 0)
                void    zeroVec();

                void    setVec(F32 x, F32 y);           // Sets LLVector2 to (x, y)
                void    setVec(const LLVector2 &vec);   // Sets LLVector2 to vec
                void    setVec(const F32 *vec);                 // Sets LLVector2 to vec

                F32             magVec() const;                         // Returns magnitude of LLVector2
                F32             magVecSquared() const;          // Returns magnitude squared of LLVector2
                F32             normVec();                                      // Normalizes and returns the magnitude of LLVector2

                BOOL            abs();                                          // sets all values to absolute value of original value (first octant), returns TRUE if changed

                const LLVector2&        scaleVec(const LLVector2& vec);                         // scales per component by vec

                BOOL isNull();                  // Returns TRUE if vector has a _very_small_ length
                BOOL isExactlyZero() const              { return !mV[VX] && !mV[VY]; }

                F32 operator[](int idx) const { return mV[idx]; }
                F32 &operator[](int idx) { return mV[idx]; }
        
                friend bool operator<(const LLVector2 &a, const LLVector2 &b);  // For sorting. x is "more significant" than y
                friend LLVector2 operator+(const LLVector2 &a, const LLVector2 &b);     // Return vector a + b
                friend LLVector2 operator-(const LLVector2 &a, const LLVector2 &b);     // Return vector a minus b
                friend F32 operator*(const LLVector2 &a, const LLVector2 &b);           // Return a dot b
                friend LLVector2 operator%(const LLVector2 &a, const LLVector2 &b);     // Return a cross b
                friend LLVector2 operator/(const LLVector2 &a, F32 k);                          // Return a divided by scaler k
                friend LLVector2 operator*(const LLVector2 &a, F32 k);                          // Return a times scaler k
                friend LLVector2 operator*(F32 k, const LLVector2 &a);                          // Return a times scaler k
                friend bool operator==(const LLVector2 &a, const LLVector2 &b);         // Return a == b
                friend bool operator!=(const LLVector2 &a, const LLVector2 &b);         // Return a != b

                friend const LLVector2& operator+=(LLVector2 &a, const LLVector2 &b);   // Return vector a + b
                friend const LLVector2& operator-=(LLVector2 &a, const LLVector2 &b);   // Return vector a minus b
                friend const LLVector2& operator%=(LLVector2 &a, const LLVector2 &b);   // Return a cross b
                friend const LLVector2& operator*=(LLVector2 &a, F32 k);                                // Return a times scaler k
                friend const LLVector2& operator/=(LLVector2 &a, F32 k);                                // Return a divided by scaler k

                friend LLVector2 operator-(const LLVector2 &a);                                 // Return vector -a

                friend std::ostream&     operator<<(std::ostream& s, const LLVector2 &a);               // Stream a
};


// Non-member functions 

F32     angle_between(const LLVector2 &a, const LLVector2 &b);  // Returns angle (radians) between a and b
BOOL are_parallel(const LLVector2 &a, const LLVector2 &b, F32 epsilon=F_APPROXIMATELY_ZERO);    // Returns TRUE if a and b are very close to parallel
F32     dist_vec(const LLVector2 &a, const LLVector2 &b);               // Returns distance between a and b
F32     dist_vec_squared(const LLVector2 &a, const LLVector2 &b);// Returns distance sqaured between a and b
F32     dist_vec_squared2D(const LLVector2 &a, const LLVector2 &b);// Returns distance sqaured between a and b ignoring Z component
LLVector2 lerp(const LLVector2 &a, const LLVector2 &b, F32 u); // Returns a vector that is a linear interpolation between a and b

// Constructors

inline LLVector2::LLVector2(void)
{
        mV[VX] = 0.f;
        mV[VY] = 0.f;
}

inline LLVector2::LLVector2(F32 x, F32 y)
{
        mV[VX] = x;
        mV[VY] = y;
}

inline LLVector2::LLVector2(const F32 *vec)
{
        mV[VX] = vec[VX];
        mV[VY] = vec[VY];
}


// Clear and Assignment Functions

inline void     LLVector2::clearVec(void)
{
        mV[VX] = 0.f;
        mV[VY] = 0.f;
}

inline void     LLVector2::zeroVec(void)
{
        mV[VX] = 0.f;
        mV[VY] = 0.f;
}

inline void     LLVector2::setVec(F32 x, F32 y)
{
        mV[VX] = x;
        mV[VY] = y;
}

inline void     LLVector2::setVec(const LLVector2 &vec)
{
        mV[VX] = vec.mV[VX];
        mV[VY] = vec.mV[VY];
}

inline void     LLVector2::setVec(const F32 *vec)
{
        mV[VX] = vec[VX];
        mV[VY] = vec[VY];
}

// LLVector2 Magnitude and Normalization Functions

inline F32              LLVector2::magVec(void) const
{
        return fsqrtf(mV[0]*mV[0] + mV[1]*mV[1]);
}

inline F32              LLVector2::magVecSquared(void) const
{
        return mV[0]*mV[0] + mV[1]*mV[1];
}

inline F32              LLVector2::normVec(void)
{
        F32 mag = fsqrtf(mV[0]*mV[0] + mV[1]*mV[1]);
        F32 oomag;

        if (mag > FP_MAG_THRESHOLD)
        {
                oomag = 1.f/mag;
                mV[0] *= oomag;
                mV[1] *= oomag;
        }
        else
        {
                mV[0] = 0.f;
                mV[1] = 0.f;
                mag = 0;
        }
        return (mag);
}

inline const LLVector2& LLVector2::scaleVec(const LLVector2& vec)
{
        mV[VX] *= vec.mV[VX];
        mV[VY] *= vec.mV[VY];

        return *this;
}

inline BOOL     LLVector2::isNull()
{
        if ( F_APPROXIMATELY_ZERO > mV[VX]*mV[VX] + mV[VY]*mV[VY] )
        {
                return TRUE;
        }
        return FALSE;
}


// LLVector2 Operators

// For sorting. By convention, x is "more significant" than y.
inline bool operator<(const LLVector2 &a, const LLVector2 &b)   
{
        if( a.mV[VX] == b.mV[VX] )
        {
                return a.mV[VY] < b.mV[VY];
        }
        else
        {
                return a.mV[VX] < b.mV[VX];
        }
}


inline LLVector2 operator+(const LLVector2 &a, const LLVector2 &b)
{
        LLVector2 c(a);
        return c += b;
}

inline LLVector2 operator-(const LLVector2 &a, const LLVector2 &b)
{
        LLVector2 c(a);
        return c -= b;
}

inline F32  operator*(const LLVector2 &a, const LLVector2 &b)
{
        return (a.mV[0]*b.mV[0] + a.mV[1]*b.mV[1]);
}

inline LLVector2 operator%(const LLVector2 &a, const LLVector2 &b)
{
        return LLVector2(a.mV[0]*b.mV[1] - b.mV[0]*a.mV[1], a.mV[1]*b.mV[0] - b.mV[1]*a.mV[0]);
}

inline LLVector2 operator/(const LLVector2 &a, F32 k)
{
        F32 t = 1.f / k;
        return LLVector2( a.mV[0] * t, a.mV[1] * t );
}

inline LLVector2 operator*(const LLVector2 &a, F32 k)
{
        return LLVector2( a.mV[0] * k, a.mV[1] * k );
}

inline LLVector2 operator*(F32 k, const LLVector2 &a)
{
        return LLVector2( a.mV[0] * k, a.mV[1] * k );
}

inline bool operator==(const LLVector2 &a, const LLVector2 &b)
{
        return (  (a.mV[0] == b.mV[0])
                        &&(a.mV[1] == b.mV[1]));
}

inline bool operator!=(const LLVector2 &a, const LLVector2 &b)
{
        return (  (a.mV[0] != b.mV[0])
                        ||(a.mV[1] != b.mV[1]));
}

inline const LLVector2& operator+=(LLVector2 &a, const LLVector2 &b)
{
        a.mV[0] += b.mV[0];
        a.mV[1] += b.mV[1];
        return a;
}

inline const LLVector2& operator-=(LLVector2 &a, const LLVector2 &b)
{
        a.mV[0] -= b.mV[0];
        a.mV[1] -= b.mV[1];
        return a;
}

inline const LLVector2& operator%=(LLVector2 &a, const LLVector2 &b)
{
        LLVector2 ret(a.mV[0]*b.mV[1] - b.mV[0]*a.mV[1], a.mV[1]*b.mV[0] - b.mV[1]*a.mV[0]);
        a = ret;
        return a;
}

inline const LLVector2& operator*=(LLVector2 &a, F32 k)
{
        a.mV[0] *= k;
        a.mV[1] *= k;
        return a;
}

inline const LLVector2& operator/=(LLVector2 &a, F32 k)
{
        F32 t = 1.f / k;
        a.mV[0] *= t;
        a.mV[1] *= t;
        return a;
}

inline LLVector2 operator-(const LLVector2 &a)
{
        return LLVector2( -a.mV[0], -a.mV[1] );
}

inline void update_min_max(LLVector2& min, LLVector2& max, const LLVector2& pos)
{
        for (U32 i = 0; i < 2; i++)
        {
                if (min.mV[i] > pos.mV[i])
                {
                        min.mV[i] = pos.mV[i];
                }
                if (max.mV[i] < pos.mV[i])
                {
                        max.mV[i] = pos.mV[i];
                }
        }
}

inline std::ostream& operator<<(std::ostream& s, const LLVector2 &a) 
{
        s << "{ " << a.mV[VX] << ", " << a.mV[VY] << " }";
        return s;
}

#endif

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