/**
 * @file mathlib.c
 * @brief math primitives
 */

/*
Copyright (C) 1997-2001 Id Software, Inc.

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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#include "cmdlib.h"
#include "mathlib.h"

vec3_t vec3_origin = {0,0,0};

/**
 * @brief
 */
double VectorLength(vec3_t v)
{
	int		i;
	double	length;

	length = 0;
	for (i=0 ; i< 3 ; i++)
		length += v[i]*v[i];
	length = sqrt (length);		/* FIXME */

	return length;
}

/**
 * @brief
 */
qboolean VectorCompare (vec3_t v1, vec3_t v2)
{
	int		i;

	for (i = 0; i < 3; i++)
		if (fabs(v1[i]-v2[i]) > EQUAL_EPSILON)
			return qfalse;

	return qtrue;
}

/**
 * @brief
 */
qboolean VectorNearer (vec3_t v1, vec3_t v2, vec3_t comp)
{
	int		i;

	for (i = 0; i < 3; i++)
		if (fabs(v1[i]-comp[i]) < fabs(v2[i]-comp[i]) )
			return qtrue;

	return qfalse;
}

/**
 * @brief
 */
vec_t Q_rint (vec_t in)
{
	return floor (in + 0.5);
}

/**
 * @brief Sets vector_out (vc) to vevtor1 (va) + scale * vector2 (vb)
 */
void VectorMA (vec3_t va, double scale, vec3_t vb, vec3_t vc)
{
	vc[0] = va[0] + scale*vb[0];
	vc[1] = va[1] + scale*vb[1];
	vc[2] = va[2] + scale*vb[2];
}

/**
 * @brief Cross prodcut of v1 and v2 saved in cross
 */
void CrossProduct (vec3_t v1, vec3_t v2, vec3_t cross)
{
	cross[0] = v1[1]*v2[2] - v1[2]*v2[1];
	cross[1] = v1[2]*v2[0] - v1[0]*v2[2];
	cross[2] = v1[0]*v2[1] - v1[1]*v2[0];
}

/**
 * @brief Dot product of v1 and v2
 */
vec_t _DotProduct (vec3_t v1, vec3_t v2)
{
	return v1[0]*v2[0] + v1[1]*v2[1] + v1[2]*v2[2];
}

/**
 * @brief
 */
void _VectorSubtract (vec3_t va, vec3_t vb, vec3_t out)
{
	out[0] = va[0]-vb[0];
	out[1] = va[1]-vb[1];
	out[2] = va[2]-vb[2];
}

/**
 * @brief
 */
void _VectorAdd (vec3_t va, vec3_t vb, vec3_t out)
{
	out[0] = va[0]+vb[0];
	out[1] = va[1]+vb[1];
	out[2] = va[2]+vb[2];
}

/**
 * @brief
 */
void _VectorCopy (vec3_t in, vec3_t out)
{
	out[0] = in[0];
	out[1] = in[1];
	out[2] = in[2];
}

/**
 * @brief Sets out to scale * v
 */
void _VectorScale (vec3_t v, vec_t scale, vec3_t out)
{
	out[0] = v[0] * scale;
	out[1] = v[1] * scale;
	out[2] = v[2] * scale;
}

/**
 * @brief Returns a vector in the same direction as the given vector but only
 * one unit long
 */
vec_t VectorNormalize (vec3_t in, vec3_t out)
{
	vec_t	length, ilength;

	length = sqrt (in[0]*in[0] + in[1]*in[1] + in[2]*in[2]);
	if (length == 0) {
		VectorClear (out);
		return 0;
	}

	ilength = 1.0/length;
	out[0] = in[0]*ilength;
	out[1] = in[1]*ilength;
	out[2] = in[2]*ilength;

	return length;
}

/**
 * @brief
 */
vec_t ColorNormalize (vec3_t in, vec3_t out)
{
	float	max, scale;

	max = in[0];
	if (in[1] > max)
		max = in[1];
	if (in[2] > max)
		max = in[2];

	if (max == 0)
		return 0;

	scale = 1.0 / max;

	VectorScale (in, scale, out);

	return max;
}

/**
 * @brief Sets vector to -1 * v
 */
void VectorInverse (vec3_t v)
{
	v[0] = -v[0];
	v[1] = -v[1];
	v[2] = -v[2];
}

/**
 * @brief Sets mins and maxs to their starting points before using AddPointToBounds
 * @sa AddPointToBounds
 */
void ClearBounds (vec3_t mins, vec3_t maxs)
{
	mins[0] = mins[1] = mins[2] = 99999;
	maxs[0] = maxs[1] = maxs[2] = -99999;
}

/**
 * @brief If the point is outside the box defined by mins and maxs, expand
 * the box to accomodate it. Sets mins and maxs to their new values
 */
void AddPointToBounds (vec3_t v, vec3_t mins, vec3_t maxs)
{
	int		i;
	vec_t	val;

	for (i = 0; i < 3; i++) {
		val = v[i];
		if (val < mins[i])
			mins[i] = val;
		if (val > maxs[i])
			maxs[i] = val;
	}
}