/*
 * vector.h: Vector3 class with Colour alias
 *
 * This file is part of Pyrit Ray Tracer.
 *
 * Copyright 2006, 2007  Radek Brich
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#ifndef VECTOR_H
#define VECTOR_H

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

using namespace std;

/**
 * three cell vector
 */
class Vector3
{
public:
	// data
	union {
		struct {
			Float x, y, z;
		};
		struct {
			Float r, g, b;
		};
		Float cell[3];
	};

	// constructors
	Vector3(): x(0.0f), y(0.0f), z(0.0f) {};
	Vector3(Float ax, Float ay, Float az): x(ax), y(ay), z(az) {};

	// index operator
	const Float &operator[](int index) const { return cell[index]; };

	bool operator==(Vector3 &v) const { return x==v.x && y==v.y && z==v.z; };

	// normalize
	Vector3 normalize()
	{
		Float f = 1.0f / mag();
		x *= f;
		y *= f;
		z *= f;
		return *this;
	}

	// get normalized copy
	Vector3 unit() const
	{
		Vector3 u(*this);
		return u.normalize();;
	}

	// square magnitude, magnitude
	Float mag2() const	{ return x * x + y * y + z * z; }
	Float mag() const	{ return sqrtf(mag2()); }

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

	// accumulate
	Vector3 operator+=(const Vector3 &v)
	{
		x += v.x;
		y += v.y;
		z += v.z;
		return *this;
	};

	// cut
	Vector3 operator/=(const Float &f)
	{
		x /= f;
		y /= f;
		z /= f;
		return *this;
	};

	// sum
	friend Vector3 operator+(const Vector3 &a, const Vector3 &b)
	{
		return Vector3(a.x + b.x, a.y + b.y, a.z + b.z);
	};

	// difference
	friend Vector3 operator-(const Vector3 &a, const Vector3 &b)
	{
		return Vector3(a.x - b.x, a.y - b.y, a.z - b.z);
	};

	// dot product
	friend Float dot(const Vector3 &a, const Vector3 &b)
	{
		return a.x * b.x + a.y * b.y + a.z * b.z;
	};

	// cross product
	friend Vector3 cross(const Vector3 &a, const Vector3 &b)
	{
		return Vector3(a.y * b.z - a.z * b.y,
			a.z * b.x - a.x * b.z,
			a.x * b.y - a.y * b.x);
	};

	// product of vector and scalar
	friend Vector3 operator*(const Vector3 &v, const Float &f)
	{
		return Vector3(f * v.x, f * v.y, f * v.z);
	}

	friend Vector3 operator*(const Float &f, const Vector3 &v)
	{
		return v * f;
	};

	// vector plus scalar
	friend Vector3 operator+(const Vector3 &v, const Float &f)
	{
		return Vector3(v.x + f, v.y + f, v.z + f);
	}

	// vector minus scalar
	friend Vector3 operator-(const Vector3 &v, const Float &f)
	{
		return Vector3(v.x - f, v.y - f, v.z - f);
	}

	// cell by cell product (only usable for colours)
	friend Vector3 operator*(const Vector3 &a,  const Vector3 &b)
	{
		return Vector3(a.x * b.x, a.y * b.y, a.z * b.z);
	};

	// print
	friend ostream & operator<<(ostream &st, const Vector3 &v)
	{
		return st << "(" << v.x << ", " << v.y  << ", " << v.z << ")";
	}
};

typedef Vector3 Colour;

#endif