/*
 *  Copyright © 2006-2016 SplinterGU (Fenix/Bennugd)
 *  Copyright © 2002-2006 Fenix Team (Fenix)
 *  Copyright © 1999-2002 José Luis Cebrián Pagüe (Fenix)
 *
 *  This file is part of Bennu - Game Development
 *
 *  This software is provided 'as-is', without any express or implied
 *  warranty. In no event will the authors be held liable for any damages
 *  arising from the use of this software.
 *
 *  Permission is granted to anyone to use this software for any purpose,
 *  including commercial applications, and to alter it and redistribute it
 *  freely, subject to the following restrictions:
 *
 *     1. The origin of this software must not be misrepresented; you must not
 *     claim that you wrote the original software. If you use this software
 *     in a product, an acknowledgment in the product documentation would be
 *     appreciated but is not required.
 *
 *     2. Altered source versions must be plainly marked as such, and must not be
 *     misrepresented as being the original software.
 *
 *     3. This notice may not be removed or altered from any source
 *     distribution.
 *
 */

#include <stdlib.h>

#include "fmath.h"

#include "bgdcore.h"

/* --------------------------------------------------------------------------- */
/* Fixed-point math routines, based on Allegro */

//#define FIXED_PREC 12

#define FIXED_PREC      10000

//#define FIXED_PREC_MED  5000
//#define FIXED_PREC_DEC  1000

/* --------------------------------------------------------------------------- */

static fixed * cos_table = NULL ;

/* --------------------------------------------------------------------------- */

fixed ftofix( float x )
{
    return ( long )( x * FIXED_PREC );
}

/* --------------------------------------------------------------------------- */

float fixtof( fixed x )
{
    return ( ( float ) x ) / FIXED_PREC ;
}

/* --------------------------------------------------------------------------- */

fixed itofix( int x )
{
    return x * FIXED_PREC ;
}

/* --------------------------------------------------------------------------- */

int fixtoi( fixed x )
{
    return x / FIXED_PREC ;
}

/* --------------------------------------------------------------------------- */

int fixceil( fixed x )
{
    int xd;

    if ( x < 0 )
    {
        xd = x % FIXED_PREC ;
        x -= ( FIXED_PREC + xd ) ;
    }
    else if ( x > 0 )
    {
        xd = x % FIXED_PREC ;
        x += ( FIXED_PREC - xd ) ;
    }

    return x ;
}

/* --------------------------------------------------------------------------- */

fixed fcos( int x )
{
    if ( x < 0 ) x = -x ;
    if ( x > 360000 ) x %= 360000 ;
    if ( x > 270000 ) return cos_table[360000 - x] ;
    if ( x > 180000 ) return -cos_table[x - 180000] ;
    if ( x > 90000 ) return -cos_table[180000 - x] ;
    return cos_table[x] ;
}

/* --------------------------------------------------------------------------- */

fixed fsin( int x )
{
    if ( x < 0 ) return -fsin( -x ) ;
    if ( x > 360000 ) x %= 360000 ;
    if ( x > 270000 ) return -cos_table[x - 270000] ;
    if ( x > 180000 ) return -cos_table[270000 - x] ;
    if ( x > 90000 ) return cos_table[x - 90000] ;
    return cos_table[90000 - x] ;
}

/* --------------------------------------------------------------------------- */

fixed fmul( int x, int y )
{
    return ftofix( fixtof( x ) * fixtof( y ) ) ;
}

/* --------------------------------------------------------------------------- */

fixed fdiv( int x, int y )
{
    return ftofix( fixtof( x ) / fixtof( y ) ) ;
}

/* --------------------------------------------------------------------------- */

void init_cos_tables()
{
    int i ;

    if ( !cos_table ) cos_table = ( fixed * ) malloc( 90001 * sizeof( fixed ) );

    for ( i = 0 ; i <= 90000 ; i++ )
    {
        cos_table[i] = ftofix( cos( i * M_PI / 180000.0 ) ) ;
    }
}

/* --------------------------------------------------------------------------- */