/*
 * Copyright (c) 2008-2009 Bill Whitacre http://rampancy.g0dsoft.com
 * 
 * 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.
*/

#include "vector.h"

void vector2_init(vector2 *vector)
{
	vector->x=0;
	vector->y=0;
}

void vector2_set(vector2 *vector,rat_real x,rat_real y)
{
	vector->x=x;
	vector->y=y;
}

void vector2_angleunit(vector2 *vector,rat_real angle)
{
	vector->x=cos(angle);
	vector->y=sin(angle);
}

rat_real vector2_dot(vector2 a,vector2 b)
{
	return a.x*b.x+a.y*b.y;
}

rat_real vector2_cross(vector2 a,vector2 b)
{
	return a.x*b.y-a.y*b.x;
}

vector2 vector2_add(vector2 a,vector2 b)
{
	vector2 n;
	n.x=a.x+b.x;
	n.y=a.y+b.y;
	return n;
}

vector2 vector2_sub(vector2 a,vector2 b)
{
	vector2 n;
	n.x=a.x-b.x;
	n.y=a.y-b.y;
	return n;
}

vector2 vector2_multf(vector2 a,rat_real val)
{
	vector2 n;
	n.x=a.x*val;
	n.y=a.y*val;
	return n;
}

vector2 vector2_multvec(vector2 a,vector2 b)
{
	vector2 n;
	n.x=a.x*b.x;
	n.y=a.y*b.y;
	return n;
}

void vector2_plus(vector2 *self,vector2 oth)		{*self=vector2_add(*self,oth);}
void vector2_minus(vector2 *self,vector2 oth)		{*self=vector2_sub(*self,oth);}
void vector2_timesf(vector2 *self,rat_real val)		{*self=vector2_multf(*self,val);}
void vector2_timesvec(vector2 *self,vector2 oth)	{*self=vector2_multvec(*self,oth);}

rat_real vector2_magnitudesquared(vector2 vector)
{
	return vector.x*vector.x+vector.y*vector.y;
}

vector2 vector2_average(vector2 *pts,unsigned int numpts)
{
	register unsigned int i;
	vector2 sum={0,0};

	if (numpts==0) return sum;
	if (numpts==1) return *pts;

	for (i=0; i<numpts; i++)
		vector2_plus(&sum,pts[i]);
	return vector2_multf(sum,1.0/numpts);
}

rat_real vector2_magnitude(vector2 vector)
{
	return sqrt(vector2_magnitudesquared(vector));
}

rat_real vector2_distancesquared(vector2 a,vector2 b)
{
	return vector2_magnitudesquared(vector2_sub(a,b));
}

void vector2_normalize(vector2 *vector)
{
	vector2_timesf(vector,1.0/vector2_magnitude(*vector));
}

vector2 vector2_getnormalized(vector2 vector)
{
	return vector2_multf(vector,1.0/vector2_magnitude(vector));
}

vector2 vector2_project(vector2 a,vector2 b)
{
	vector2 proj;
	rat_real dp;
	
	dp=vector2_dot(a,b);
	
	proj.x=(dp/(b.x*b.x+b.y*b.y))*b.x;
	proj.y=(dp/(b.x*b.x+b.y*b.y))*b.y;

	return proj;
}

rat_real vector2_distance(vector2 a,vector2 b)
{
	return sqrt(vector2_distancesquared(a,b));
}

vector2 vector2_reflect(vector2 instance,vector2 normal)
{
	return vector2_sub(instance,vector2_multf(normal,vector2_dot(instance,normal)*2.0));
}

rat_real vector2_angle(vector2 vector)
{
	return atan2(vector.y,vector.x);
}

vector2 vector2_perp_left(vector2 vector)
{
	vector2 perp;
	vector2_set(&perp,-vector.y,vector.x);
	return perp;
}

vector2 vector2_perp_right(vector2 vector)
{
	vector2 perp;
	vector2_set(&perp,vector.y,-vector.x);
	return perp;
}

vector2 vector2_negative(vector2 vector)
{
	vector2 neg;
	vector2_set(&neg,-vector.x,-vector.y);
	return neg;
}

vector2 vector2_getrotated(vector2 vector,rat_real angle)
{
	vector2 out;
	rotate_points2(angle,(rat_real *)&vector.x,(rat_real *)&out.x,1);
	return out;
}

vector2 vector2_getscaled(vector2 vector,vector2 scalar)
{
	vector2 out;
	scale_points2((rat_real *)&scalar.x,(rat_real *)&vector.x,(rat_real *)&out.x,1);
	return out;
}

vector2 vector2_gettranslated(vector2 vector,vector2 trans)
{
	vector2 out;
	translate_points2((rat_real *)&trans.x,(rat_real *)&vector.x,(rat_real *)&out.x,1);
	return out;
}

void vector2_rotate(vector2 *self,rat_real angle)
{
	*self=vector2_getrotated(*self,angle);
}

void vector2_scale(vector2 *self,vector2 scalar)
{
	*self=vector2_getscaled(*self,scalar);
}

void vector2_translate(vector2 *self,vector2 trans)
{
	*self=vector2_gettranslated(*self,trans);
}

vector2 vector2_world_to_local(vector2 vector,vector2 hull_pos,rat_real hull_angle)
{
	return vector2_getrotated(vector2_sub(vector,hull_pos),-hull_angle);
}

vector2 vector2_local_to_world(vector2 vector,vector2 hull_pos,rat_real hull_angle)
{
	return vector2_add(vector2_getrotated(vector,hull_angle),hull_pos);
}