/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 *
 */

/*
 * This code is based on Broken Sword 2.5 engine
 *
 * Copyright (c) Malte Thiesen, Daniel Queteschiner and Michael Elsdoerfer
 *
 * Licensed under GNU GPL v2
 *
 */

/*
    BS_Vertex
    ---------

    Autor: Malte Thiesen
*/

#ifndef SWORD25_VERTEX_H
#define SWORD25_VERTEX_H

// Includes
#include <math.h>
#include "sword25/kernel/common.h"

namespace Lua {

// Forward declarations
struct lua_State;

}

using namespace Lua;

namespace Sword25 {

/**
 * Defines a 2-D Vertex
 */
class Vertex {
public:
	Vertex() : X(0), Y(0) {};
	Vertex(int X_, int Y_) {
		this->X = X_;
		this->Y = Y_;
	}

	int X;
	int Y;

	/**
	 * Compares two Vertecies.
	 */
	inline bool operator==(const Vertex &rhs) const {
		if (X == rhs.X && Y == rhs.Y) return true;
		return false;
	}
	/**
	 * Compares two Vertecies.
	 */
	inline bool operator!=(const Vertex &rhs) const {
		if (X != rhs.X || Y != rhs.Y) return true;
		return false;
	}
	/**
	 * Adds a vertex to vertex
	 */
	inline void operator+=(const Vertex &Delta) {
		X += Delta.X;
		Y += Delta.Y;
	}

	/**
	 * Subtracts a vertex from a vertex
	 */
	inline void operator-=(const Vertex &Delta) {
		X -= Delta.X;
		Y -= Delta.Y;
	}

	/**
	 * Adds two vertecies
	 */
	inline Vertex operator+(const Vertex &Delta) const {
		return Vertex(X + Delta.X, Y + Delta.Y);
	}

	/**
	 * Subtracts two vertecies
	 */
	inline Vertex operator-(const Vertex &Delta) const {
		return Vertex(X - Delta.X, Y - Delta.Y);
	}

	/**
	 * Calculates the square of the distance between two Vertecies.
	 * @param Vertex        The vertex for which the distance is to be calculated
	 * @return              Returns the square of the distance between itself and the passed vertex
	 * @remark              If only distances should be compared, this method should be used because
	 * it is faster than Distance()
	 */
	inline int Distance2(const Vertex &vertex) const {
		return (X - vertex.X) * (X - vertex.X) + (Y - vertex.Y) * (Y - vertex.Y);
	}

	/**
	 * Calculates the square of the distance between two Vertecies.
	 * @param Vertex        The vertex for which the distance is to be calculated
	 * @return              Returns the square of the distance between itself and the passed vertex
	 * @remark              If only distances should be compared, Distance2() should be used, since it is faster.
	 */
	inline int Distance(const Vertex &vertex) const {
		return (int)(sqrtf(static_cast<float>(Distance2(vertex))) + 0.5);
	}

	/**
	 * Calculates the cross product of the vertex with another vertex. Here the Vertecies will be
	 * interpreted as vectors.
	 * @param Vertex        The second vertex
	 * @return              Returns the cross product of this vertex and the passed vertex.
	 */
	inline int ComputeCrossProduct(const Vertex &vertex) const {
		return X * vertex.Y - vertex.X * Y;
	}

	/**
	 * Returns the dot product of this vertex with another vertex. Here the Vertecies are interpreted as vectors.
	 * @param Vertex        The second vertex
	 * @return              Returns the dot product of this vertex and the passed vertex.
	 */
	inline int ComputeDotProduct(const Vertex &vertex) const {
		return X * vertex.X + Y * vertex.Y;
	}

	/**
	 * Calculates the angle between this vertex and another vertex. Here the Vertecies are interpreted as vectors.
	 * @param Vertex        The second vertex
	 * @return              Returns the angle between this vertex and the passed vertex in radians.
	 */
	inline float ComputeAngle(const Vertex &vertex) const {
		return atan2f(static_cast<float>(ComputeCrossProduct(vertex)), static_cast<float>(ComputeDotProduct(vertex)));
	}

	/**
	 * Calculates the length of the vector
	 */
	inline float ComputeLength() const {
		return sqrtf(static_cast<float>(X * X + Y * Y));
	}

	static Vertex &LuaVertexToVertex(lua_State *L, int StackIndex, Vertex &vertex);
	static void VertexToLuaVertex(lua_State *L, const Vertex &vertex);
};

} // End of namespace Sword25

#endif