raze-gles/polymer/eduke32/source/jmact/mathutil.c

/*
 * mathutil.c
 * Mathematical utility functions to emulate MACT
 *
 * by Jonathon Fowler
 *
 * Since we weren't given the source for MACT386.LIB so I've had to do some
 * creative interpolation here.
 *
 */
//-------------------------------------------------------------------------
/*
Duke Nukem Copyright (C) 1996, 2003 3D Realms Entertainment

This file is part of Duke Nukem 3D version 1.5 - Atomic Edition

Duke Nukem 3D 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 <limits.h>
#include "compat.h"
#include "pragmas.h"

// I wonder if it's faster to use Ken's functions here...

int32_t FindDistance2D(int32_t x, int32_t y)
{
    if ((x=klabs(x)) < (y=klabs(y))) swaplong(&x,&y);

    {
        int32_t t = y + (y>>1);
        return (x - (x>>5) - (x>>7)  + (t>>2) + (t>>6));
    }
}

int32_t FindDistance3D(int32_t x, int32_t y, int32_t z)
{
    if ((x=klabs(x)) < (y=klabs(y))) swaplong(&x,&y);
    if (x < (z=klabs(z))) swaplong(&x,&z);

    {
        int32_t t = y + z;
        return (x - (x>>4) + (t>>2) + (t>>3));
    }
}