160 lines
3.0 KiB
C++
160 lines
3.0 KiB
C++
#ifndef GOMEZ_Vector_H
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#define GOMEZ_Vector_H
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#include <cmath>
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/**
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* Taken from:
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* http://www.gamasutra.com/features/19990702/data_structures_01.htm
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* http://www.gamasutra.com/features/19991018/Gomez_1.htm
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*
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* Both by Miguel Gomez
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*/
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namespace GomezMath {
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// A floating point number
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//
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typedef float Scalar;
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//
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// A 3D vector
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//
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class Vector
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{
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public:
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Scalar x, y, z; //x,y,z coordinates
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public:
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Vector ():x (0), y (0), z (0)
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{
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}
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Vector (const Scalar & a, const Scalar & b, const Scalar & c):x (a), y (b),
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z (c)
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{
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}
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//index a component
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//NOTE: returning a reference allows
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//you to assign the indexed element
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Scalar & operator [](const long i)
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{
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return *((&x) + i);
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}
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//compare
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const bool operator == (const Vector & v) const
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{
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return (v.x == x && v.y == y && v.z == z);
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}
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const bool operator != (const Vector & v) const
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{
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return !(v == *this);
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}
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//negate
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const Vector operator - () const
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{
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return Vector (-x, -y, -z);
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}
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//assign
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const Vector & operator = (const Vector & v)
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{
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x = v.x;
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y = v.y;
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z = v.z;
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return *this;
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}
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//increment
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const Vector & operator += (const Vector & v)
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{
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x += v.x;
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y += v.y;
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z += v.z;
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return *this;
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}
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//decrement
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const Vector & operator -= (const Vector & v)
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{
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x -= v.x;
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y -= v.y;
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z -= v.z;
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return *this;
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}
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//self-multiply
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const Vector & operator *= (const Scalar & s)
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{
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x *= s;
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y *= s;
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z *= s;
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return *this;
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}
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//self-divide
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const Vector & operator /= (const Scalar & s)
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{
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const Scalar r = 1 / s;
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x *= r;
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y *= r;
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z *= r;
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return *this;
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}
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//add
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const Vector operator + (const Vector & v) const
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{
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return Vector (x + v.x, y + v.y, z + v.z);
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}
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//subtract
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const Vector operator - (const Vector & v) const
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{
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return Vector (x - v.x, y - v.y, z - v.z);
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}
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//post-multiply by a scalar
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const Vector operator * (const Scalar & s) const
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{
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return Vector (x * s, y * s, z * s);
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}
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//pre-multiply by a scalar
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friend inline const Vector operator * (const Scalar & s, const Vector & v)
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{
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return v * s;
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}
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//divide
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const Vector operator / (Scalar s) const
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{
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s = 1 / s;
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return Vector (s * x, s * y, s * z);
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}
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//cross product
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const Vector cross (const Vector & v) const
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{
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//Davis, Snider, "Introduction to Vector Analysis", p. 44
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return Vector (y * v.z - z * v.y, z * v.x - x * v.z, x * v.y - y * v.x);
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}
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//scalar dot product
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const Scalar dot (const Vector & v) const
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{
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return x * v.x + y * v.y + z * v.z;
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}
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//length
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const Scalar length () const
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{
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return (Scalar) sqrt ((double) this->dot (*this));
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}
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//unit vector
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const Vector unit () const
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{
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return (*this) / length ();
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}
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//make this a unit vector
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void normalize ()
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{
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(*this) /= length ();
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}
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//equal within an error ‘e’
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const bool nearlyEquals (const Vector & v, const Scalar e) const
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{
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return fabs (x - v.x) < e && fabs (y - v.y) < e && fabs (z - v.z) < e;
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}
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};
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//
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// A 3D position
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//
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typedef Vector Point;
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}
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#endif
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