/**
  @file Vector3.h
 
  3D vector class
 
  @maintainer Morgan McGuire, http://graphics.cs.williams.edu

  @created 2001-06-02
  @edited  2009-11-01
  Copyright 2000-2009, Morgan McGuire.
  All rights reserved.
 */

#ifndef G3D_Vector3_h
#define G3D_Vector3_h

#include "G3D/platform.h"
#include "G3D/g3dmath.h"
#include "G3D/Random.h"
#include "G3D/Vector2.h"
#include "G3D/Table.h"
#include "G3D/HashTrait.h"
#include "G3D/PositionTrait.h"
#include "G3D/Vector2.h"
#include <iostream>
#include <string>

namespace G3D {

class Vector2;
class Vector4;
class Vector4int8;
class Vector3int32;
class Any;

/**
  <B>Swizzles</B>
 Vector classes have swizzle operators, e.g. <CODE>v.xy()</CODE>, that
 allow selection of arbitrary sub-fields.  These cannot be used as write 
 masks.  Examples

  <PRE>
Vector3 v(1, 2, 3);
Vector3 j;
Vector2 b;

b = v.xz();
j = b.xx();
</PRE>


  <B>Warning</B>

 Do not subclass-- this implementation makes assumptions about the
 memory layout.
 */
class Vector3 {
public:

    // coordinates
    float x, y, z;

private:

    // Hidden operators
    bool operator<(const Vector3&) const;
    bool operator>(const Vector3&) const;
    bool operator<=(const Vector3&) const;
    bool operator>=(const Vector3&) const;

public:
    /** Initializes to zero */
    Vector3();

    /** \param any Must either Vector3(#, #, #) or Vector3 {x = #, y = #, z = #}*/
    Vector3(const Any& any);
    
    /** Converts the Vector3 to an Any. */
    operator Any() const;

    /** Divides by 127 */
    Vector3(const Vector4int8&);
    Vector3(const class Vector3int32& v);
    explicit Vector3(class BinaryInput& b);
    Vector3(float _x, float _y, float _z);
    explicit Vector3(const class Vector2& v, float _z);
    explicit Vector3(float coordinate[3]);
    explicit Vector3(double coordinate[3]);
    Vector3(const class Vector3int16& v);
	explicit Vector3(class TextInput& t);
    explicit Vector3(const class Color3& c);

	/** Format is three float32's */
    void serialize(class BinaryOutput& b) const;
    void deserialize(class BinaryInput& b);

	/** Format is "(%f, %f, %f)" */
    void serialize(class TextOutput& t) const;
    void deserialize(class TextInput& t);

    // access vector V as V[0] = V.x, V[1] = V.y, V[2] = V.z
    //
    // WARNING.  These member functions rely on
    // (1) Vector3 not having virtual functions
    // (2) the data packed in a 3*sizeof(float) memory block
    const float& __fastcall operator[] (int i) const;
    float& operator[] (int i);

    enum Axis {X_AXIS=0, Y_AXIS=1, Z_AXIS=2, DETECT_AXIS=-1};

    /**
     Returns the largest dimension.  Particularly convenient for determining
     which plane to project a triangle onto for point-in-polygon tests.
     */
    Axis primaryAxis() const;

    // assignment and comparison
    Vector3& __fastcall operator= (const Vector3& rkVector);
    bool operator== (const Vector3& rkVector) const;
    bool operator!= (const Vector3& rkVector) const;
    size_t hashCode() const;
    bool fuzzyEq(const Vector3& other) const;
    bool fuzzyNe(const Vector3& other) const;

    /** Returns true if this vector has finite length. */
    bool isFinite() const;

    /** Returns true if this vector has length ~= 0 */
    bool isZero() const;

    /** Returns true if this vector has length ~= 1 */
    bool isUnit() const;
    
    // arithmetic operations
    Vector3 __fastcall operator+ (const Vector3& v) const;
    Vector3 __fastcall operator- (const Vector3& v) const;
    Vector3 __fastcall operator* (float s) const;
    inline Vector3 __fastcall operator/ (float s) const {
        return *this * (1.0f / s);
    }
    Vector3 __fastcall operator* (const Vector3& v) const;
    Vector3 __fastcall operator/ (const Vector3& v) const;
    Vector3 __fastcall operator- () const;

    // arithmetic updates
    Vector3& __fastcall operator+= (const Vector3& v);
    Vector3& __fastcall operator-= (const Vector3& v);
    Vector3& __fastcall operator*= (float s);
    inline Vector3& __fastcall operator/= (float s) {
        return (*this *= (1.0f / s));
    }
    Vector3& __fastcall operator*= (const Vector3& v);
    Vector3& __fastcall operator/= (const Vector3& v);

    /** Same as magnitude */
	float length() const;

    float magnitude() const;
    
    /**
     The result is a nan vector if the length is almost zero.
     */
    Vector3 direction() const;

    /**
     Potentially less accurate but faster than direction().
     Only works if System::hasSSE is true.
     */
    Vector3 fastDirection() const;

    /**
     Reflect this vector about the (not necessarily unit) normal.
     Assumes that both the before and after vectors point away from
     the base of the normal.

     Note that if used for a collision or ray reflection you
     must negate the resulting vector to get a direction pointing
     <I>away</I> from the collision.

     <PRE>
       V'    N      V
                 
         r   ^   -,
          \  |  /
            \|/
     </PRE>

     See also Vector3::reflectionDirection
     */
    Vector3 reflectAbout(const Vector3& normal) const;

    /**
      See also G3D::Ray::reflect.
      The length is 1. 
     <PRE>
       V'    N       V
                 
         r   ^    /
          \  |  /
            \|'-
     </PRE>
     */
    Vector3 reflectionDirection(const Vector3& normal) const;
    

    /**
     Returns Vector3::zero() if the length is nearly zero, otherwise
     returns a unit vector.
     */
    inline Vector3 directionOrZero() const {
        float mag = magnitude();
        if (G3D::fuzzyEq(mag, 0.0f)) {
            return Vector3::zero();
        } else if (G3D::fuzzyEq(mag, 1.0f)) {
            return *this;
        } else {
            return *this * (1.0f / mag);
        }
    }

    /**
     Returns the direction of a refracted ray,
     where iExit is the index of refraction for the
     previous material and iEnter is the index of refraction
     for the new material.  Like Vector3::reflectionDirection,
     the result has length 1 and is 
     pointed <I>away</I> from the intersection.

     Returns Vector3::zero() in the case of total internal refraction.

     @param iOutside The index of refraction (eta) outside
     (on the <I>positive</I> normal side) of the surface.

     @param iInside The index of refraction (eta) inside
     (on the <I>negative</I> normal side) of the surface.

     See also G3D::Ray::refract.
     <PRE>
              N      V
                  
              ^    /
              |  /
              |'-
          __--
     V'<--
     </PRE>
     */
    Vector3 refractionDirection(
        const Vector3&  normal,
        float           iInside,
        float           iOutside) const;

    /** Synonym for direction */
    inline Vector3 unit() const {
        return direction();
    }

    /** Returns a normalized vector.  May be computed with lower
        precision than unit */
    inline Vector3 fastUnit() const {
        return fastDirection();
    }

    /** Same as squaredMagnitude */
    float squaredLength() const;

    float squaredMagnitude () const;
	
    float __fastcall dot(const Vector3& rkVector) const;
    
    float unitize(float tolerance = 1e-06);

    /** Cross product.  Note that two cross products in a row
        can be computed more cheaply: v1 x (v2 x v3) = (v1 dot v3) v2  - (v1 dot v2) v3.
      */
    Vector3 __fastcall cross(const Vector3& rkVector) const;
    Vector3 unitCross(const Vector3& rkVector) const;

    /**
     Returns a matrix such that v.cross() * w = v.cross(w).
     <PRE>
     [ 0  -v.z  v.y ]
     [ v.z  0  -v.x ]
     [ -v.y v.x  0  ]
     </PRE>
     */
    class Matrix3 cross() const;

    Vector3 __fastcall min(const Vector3 &v) const;
    Vector3 __fastcall max(const Vector3 &v) const;

    /** Smallest element */
    inline float min() const {
        return G3D::min(G3D::min(x, y), z);
    }

    /** Largest element */
    inline float max() const {
        return G3D::max(G3D::max(x, y), z);
    }

    std::string toString() const;

    inline Vector3 clamp(const Vector3& low, const Vector3& high) const {
        return Vector3(
            G3D::clamp(x, low.x, high.x),
            G3D::clamp(y, low.y, high.y),
            G3D::clamp(z, low.z, high.z));
    }

    inline Vector3 clamp(float low, float high) const {
        return Vector3(
            G3D::clamp(x, low, high),
            G3D::clamp(y, low, high),
            G3D::clamp(z, low, high));
    }

    /**
     Linear interpolation
     */
    inline Vector3 lerp(const Vector3& v, float alpha) const {
        return (*this) + (v - *this) * alpha; 
    }

    /** Gram-Schmidt orthonormalization. */
    static void orthonormalize (Vector3 akVector[3]);

    /** \brief Random unit vector, uniformly distributed on the sphere. 
    
       Distribution rendered by G3D::DirectionHistogram:
       \image html vector3-random.png
      */
    static Vector3 random(Random& r = Random::common());

    /** \brief Random unit vector, distributed according to \f$\max(\cos \theta,0)\f$.

        That is, so that the probability of \f$\vec{V}\f$ is proportional 
        to \f$\max(\vec{v} \cdot \vec{n}, 0)\f$.  Useful in photon mapping for 
        Lambertian scattering.

        Distribution rendered by G3D::DirectionHistogram:
        \image html vector3-coshemirandom.png

        \param n Unit vector at the center of the distribution.

        @cite Henrik Wann Jensen, Realistic Image Synthesis using Photon Mapping eqn 2.24
    */
    static Vector3 cosHemiRandom(const Vector3& n, Random& r = Random::common());

    /** \brief Random unit vector, distributed according to \f$\max(\cos^k \theta,0)\f$.

        That is, so that the probability of \f$\vec{V}\f$ is
        proportional to \f$\max((\vec{v} \cdot \vec{n})^k, 0)\f$.
        Useful in photon mapping for glossy scattering.

        Distribution rendered by G3D::DirectionHistogram:
        \image html vector3-cospowhemirandom.png

        \param n Unit vector at the center of the distribution.

        @cite Ashikhmin and Shirley, An anisotropic Phong BRDF model, Journal of Graphics Tools, 2002
    */
    static Vector3 cosPowHemiRandom(const Vector3& n, const float k, Random& r = Random::common());

    /**
     \brief Random vector distributed over the hemisphere about normal.

     Distribution rendered by G3D::DirectionHistogram:
      \image html vector3-hemirandom.png
     */
    static Vector3 hemiRandom(const Vector3& normal, Random& r = Random::common());

    /** Input W must be initialize to a nonzero vector, output is {U,V,W}
        an orthonormal basis.  A hint is provided about whether or not W
        is already unit length. 
        @deprecated Use getTangents
    */
    static void generateOrthonormalBasis (Vector3& rkU, Vector3& rkV,
                                          Vector3& rkW, bool bUnitLengthW = true);

    inline float sum() const {
        return x + y + z;
    }

    inline float average() const {
        return sum() / 3.0f;
    }

    // Special values.
    static const Vector3& zero();
    static const Vector3& one();
    static const Vector3& unitX();
    static const Vector3& unitY();
    static const Vector3& unitZ();
    static const Vector3& inf();
    static const Vector3& nan();
    
    /** Smallest (most negative) representable vector */
    static const Vector3& minFinite();

    /** Largest representable vector */
    static const Vector3& maxFinite();


    /** Creates two orthonormal tangent vectors X and Y such that
        if Z = this, X x Y = Z.*/
    inline void getTangents(Vector3& X, Vector3& Y) const {
        debugAssertM(G3D::fuzzyEq(length(), 1.0f), 
                     "makeAxes requires Z to have unit length");
        
        // Choose another vector not perpendicular
        X = (abs(x) < 0.9f) ? Vector3::unitX() : Vector3::unitY();
        
        // Remove the part that is parallel to Z
        X -= *this * this->dot(X);
        X /= X.length();
    
        Y = this->cross(X);
    }


    // 2-char swizzles

    Vector2 xx() const;
    Vector2 yx() const;
    Vector2 zx() const;
    Vector2 xy() const;
    Vector2 yy() const;
    Vector2 zy() const;
    Vector2 xz() const;
    Vector2 yz() const;
    Vector2 zz() const;

    // 3-char swizzles

    Vector3 xxx() const;
    Vector3 yxx() const;
    Vector3 zxx() const;
    Vector3 xyx() const;
    Vector3 yyx() const;
    Vector3 zyx() const;
    Vector3 xzx() const;
    Vector3 yzx() const;
    Vector3 zzx() const;
    Vector3 xxy() const;
    Vector3 yxy() const;
    Vector3 zxy() const;
    Vector3 xyy() const;
    Vector3 yyy() const;
    Vector3 zyy() const;
    Vector3 xzy() const;
    Vector3 yzy() const;
    Vector3 zzy() const;
    Vector3 xxz() const;
    Vector3 yxz() const;
    Vector3 zxz() const;
    Vector3 xyz() const;
    Vector3 yyz() const;
    Vector3 zyz() const;
    Vector3 xzz() const;
    Vector3 yzz() const;
    Vector3 zzz() const;

    // 4-char swizzles

    Vector4 xxxx() const;
    Vector4 yxxx() const;
    Vector4 zxxx() const;
    Vector4 xyxx() const;
    Vector4 yyxx() const;
    Vector4 zyxx() const;
    Vector4 xzxx() const;
    Vector4 yzxx() const;
    Vector4 zzxx() const;
    Vector4 xxyx() const;
    Vector4 yxyx() const;
    Vector4 zxyx() const;
    Vector4 xyyx() const;
    Vector4 yyyx() const;
    Vector4 zyyx() const;
    Vector4 xzyx() const;
    Vector4 yzyx() const;
    Vector4 zzyx() const;
    Vector4 xxzx() const;
    Vector4 yxzx() const;
    Vector4 zxzx() const;
    Vector4 xyzx() const;
    Vector4 yyzx() const;
    Vector4 zyzx() const;
    Vector4 xzzx() const;
    Vector4 yzzx() const;
    Vector4 zzzx() const;
    Vector4 xxxy() const;
    Vector4 yxxy() const;
    Vector4 zxxy() const;
    Vector4 xyxy() const;
    Vector4 yyxy() const;
    Vector4 zyxy() const;
    Vector4 xzxy() const;
    Vector4 yzxy() const;
    Vector4 zzxy() const;
    Vector4 xxyy() const;
    Vector4 yxyy() const;
    Vector4 zxyy() const;
    Vector4 xyyy() const;
    Vector4 yyyy() const;
    Vector4 zyyy() const;
    Vector4 xzyy() const;
    Vector4 yzyy() const;
    Vector4 zzyy() const;
    Vector4 xxzy() const;
    Vector4 yxzy() const;
    Vector4 zxzy() const;
    Vector4 xyzy() const;
    Vector4 yyzy() const;
    Vector4 zyzy() const;
    Vector4 xzzy() const;
    Vector4 yzzy() const;
    Vector4 zzzy() const;
    Vector4 xxxz() const;
    Vector4 yxxz() const;
    Vector4 zxxz() const;
    Vector4 xyxz() const;
    Vector4 yyxz() const;
    Vector4 zyxz() const;
    Vector4 xzxz() const;
    Vector4 yzxz() const;
    Vector4 zzxz() const;
    Vector4 xxyz() const;
    Vector4 yxyz() const;
    Vector4 zxyz() const;
    Vector4 xyyz() const;
    Vector4 yyyz() const;
    Vector4 zyyz() const;
    Vector4 xzyz() const;
    Vector4 yzyz() const;
    Vector4 zzyz() const;
    Vector4 xxzz() const;
    Vector4 yxzz() const;
    Vector4 zxzz() const;
    Vector4 xyzz() const;
    Vector4 yyzz() const;
    Vector4 zyzz() const;
    Vector4 xzzz() const;
    Vector4 yzzz() const;
    Vector4 zzzz() const;

    /** Can be passed to ignore a vector3 parameter */
    static Vector3& ignore();
};

inline G3D::Vector3 operator*(float s, const G3D::Vector3& v) {
    return v * s;
}

inline G3D::Vector3 operator*(double s, const G3D::Vector3& v) {
    return v * (float)s;
}

inline G3D::Vector3 operator*(int s, const G3D::Vector3& v) {
    return v * (float)s;
}

std::ostream& operator<<(std::ostream& os, const Vector3&);


void serialize(const Vector3::Axis& a, class BinaryOutput& bo);
void deserialize(Vector3::Axis& a, class BinaryInput& bo);


//----------------------------------------------------------------------------
inline Vector3::Vector3() : x(0.0f), y(0.0f), z(0.0f) {
}

//----------------------------------------------------------------------------

inline Vector3::Vector3 (float fX, float fY, float fZ) : x(fX), y(fY), z(fZ) {
}

//----------------------------------------------------------------------------
inline Vector3::Vector3 (float V[3]) : x(V[0]), y(V[1]), z(V[2]){
}

//----------------------------------------------------------------------------
inline Vector3::Vector3 (double V[3]) : x((float)V[0]), y((float)V[1]), z((float)V[2]){
}

//----------------------------------------------------------------------------
inline const float& Vector3::operator[] (int i) const {
    return ((float*)this)[i];
}

inline float& Vector3::operator[] (int i) {
    return ((float*)this)[i];
}


//----------------------------------------------------------------------------
inline Vector3& Vector3::operator= (const Vector3& rkVector) {
    x = rkVector.x;
    y = rkVector.y;
    z = rkVector.z;
    return *this;
}

//----------------------------------------------------------------------------

inline bool Vector3::fuzzyEq(const Vector3& other) const {
    return G3D::fuzzyEq((*this - other).squaredMagnitude(), 0);
}

//----------------------------------------------------------------------------

inline bool Vector3::fuzzyNe(const Vector3& other) const {
    return G3D::fuzzyNe((*this - other).squaredMagnitude(), 0);
}

//----------------------------------------------------------------------------

inline bool Vector3::isFinite() const {
    return G3D::isFinite(x) && G3D::isFinite(y) && G3D::isFinite(z);
}

//----------------------------------------------------------------------------
inline bool Vector3::operator== (const Vector3& rkVector) const {
    return ( x == rkVector.x && y == rkVector.y && z == rkVector.z );
}

//----------------------------------------------------------------------------
inline bool Vector3::operator!= (const Vector3& rkVector) const {
    return ( x != rkVector.x || y != rkVector.y || z != rkVector.z );
}

//----------------------------------------------------------------------------
inline Vector3 Vector3::operator+ (const Vector3& rkVector) const {
    return Vector3(x + rkVector.x, y + rkVector.y, z + rkVector.z);
}

//----------------------------------------------------------------------------
inline Vector3 Vector3::operator- (const Vector3& rkVector) const {
    return Vector3(x - rkVector.x, y - rkVector.y, z - rkVector.z);
}

//----------------------------------------------------------------------------
inline Vector3 Vector3::operator* (const Vector3& rkVector) const {
    return Vector3(x * rkVector.x, y * rkVector.y, z * rkVector.z);
}

inline Vector3 Vector3::operator*(float f) const {
    return Vector3(x * f, y * f, z * f);
}

//----------------------------------------------------------------------------
inline Vector3 Vector3::operator/ (const Vector3& rkVector) const {
    return Vector3(x / rkVector.x, y / rkVector.y, z / rkVector.z);
}

//----------------------------------------------------------------------------
inline Vector3 Vector3::operator- () const {
    return Vector3(-x, -y, -z);
}

//----------------------------------------------------------------------------
inline Vector3& Vector3::operator+= (const Vector3& rkVector) {
    x += rkVector.x;
    y += rkVector.y;
    z += rkVector.z;
    return *this;
}

//----------------------------------------------------------------------------
inline Vector3& Vector3::operator-= (const Vector3& rkVector) {
    x -= rkVector.x;
    y -= rkVector.y;
    z -= rkVector.z;
    return *this;
}

//----------------------------------------------------------------------------
inline Vector3& Vector3::operator*= (float fScalar) {
    x *= fScalar;
    y *= fScalar;
    z *= fScalar;
    return *this;
}

//----------------------------------------------------------------------------
inline Vector3& Vector3::operator*= (const Vector3& rkVector) {
    x *= rkVector.x;
    y *= rkVector.y;
    z *= rkVector.z;
    return *this;
}

//----------------------------------------------------------------------------
inline Vector3& Vector3::operator/= (const Vector3& rkVector) {
    x /= rkVector.x;
    y /= rkVector.y;
    z /= rkVector.z;
    return *this;
}

//----------------------------------------------------------------------------
inline float Vector3::squaredMagnitude () const {
    return x*x + y*y + z*z;
}

//----------------------------------------------------------------------------
inline float Vector3::squaredLength () const {
    return squaredMagnitude();
}

//----------------------------------------------------------------------------
inline float Vector3::magnitude() const {
    return ::sqrtf(x*x + y*y + z*z);
}

//----------------------------------------------------------------------------
inline float Vector3::length() const {
    return magnitude();
}

//----------------------------------------------------------------------------
inline Vector3 Vector3::direction () const {
    const float lenSquared = squaredMagnitude();
    const float invSqrt = 1.0f / sqrtf(lenSquared);
    return Vector3(x * invSqrt, y * invSqrt, z * invSqrt);
}

//----------------------------------------------------------------------------

inline Vector3 Vector3::fastDirection () const {
    float lenSquared = x * x + y * y + z * z;
    float invSqrt = rsq(lenSquared);
    return Vector3(x * invSqrt, y * invSqrt, z * invSqrt);
}

//----------------------------------------------------------------------------
inline float Vector3::dot (const Vector3& rkVector) const {
    return x*rkVector.x + y*rkVector.y + z*rkVector.z;
}

//----------------------------------------------------------------------------
inline Vector3 Vector3::cross (const Vector3& rkVector) const {
    return Vector3(y*rkVector.z - z*rkVector.y, z*rkVector.x - x*rkVector.z,
                   x*rkVector.y - y*rkVector.x);
}

//----------------------------------------------------------------------------
inline Vector3 Vector3::unitCross (const Vector3& rkVector) const {
    Vector3 kCross(y*rkVector.z - z*rkVector.y, z*rkVector.x - x*rkVector.z,
                   x*rkVector.y - y*rkVector.x);
    kCross.unitize();
    return kCross;
}

//----------------------------------------------------------------------------
inline Vector3 Vector3::min(const Vector3 &v) const {
    return Vector3(G3D::min(v.x, x), G3D::min(v.y, y), G3D::min(v.z, z));
}

//----------------------------------------------------------------------------
inline Vector3 Vector3::max(const Vector3 &v) const {
    return Vector3(G3D::max(v.x, x), G3D::max(v.y, y), G3D::max(v.z, z));
}

//----------------------------------------------------------------------------
inline bool Vector3::isZero() const {
    return G3D::fuzzyEq(squaredMagnitude(), 0.0f);
}

//----------------------------------------------------------------------------

inline bool Vector3::isUnit() const {
    return G3D::fuzzyEq(squaredMagnitude(), 1.0f);
}

} // namespace G3D


template <>
struct HashTrait<G3D::Vector3> {
    static size_t hashCode(const G3D::Vector3& key) {
        return key.hashCode();
    }
};


template<> struct PositionTrait<class G3D::Vector2> {
    static void getPosition(const G3D::Vector2& v, G3D::Vector3& p) { p = G3D::Vector3(v, 0); }
};

template<> struct PositionTrait<class G3D::Vector3> {
    static void getPosition(const G3D::Vector3& v, G3D::Vector3& p) { p = v; }
};


#endif