mathlib.c

/*  Copyright (C) 1996-1997  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

    See file, 'COPYING', for details.
*/

/*
 * common/mathlib.c
 * Modifications by Kevin Shanahan, 1999-2000
 */

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

vec3_t vec3_origin = {0,0,0};


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;
}

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 false;
    
    return true;
}

vec_t Q_rint (vec_t in)
{
    return floor (in + 0.5);
}

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];
}

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];
}

vec_t _DotProduct (vec3_t v1, vec3_t v2)
{
    return v1[0]*v2[0] + v1[1]*v2[1] + v1[2]*v2[2];
}

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];
}

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];
}

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

vec_t VectorNormalize (vec3_t v)
{
    int    i;
    double length;

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

void VectorInverse (vec3_t v)
{
    v[0] = -v[0];
    v[1] = -v[1];
    v[2] = -v[2];
}

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;
}