//-------------------------------------------------------------------------
/*
Copyright (C) 1997, 2005 - 3D Realms Entertainment

This file is part of Shadow Warrior version 1.2

Shadow Warrior 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

Original Source: 1997 - Frank Maddin and Jim Norwood
Prepared for public release: 03/28/2005 - Charlie Wiederhold, 3D Realms
*/
//-------------------------------------------------------------------------

#include "compat.h"
#include "pragmas.h"

#include "interp.h"

#define MAXINTERPOLATIONS 1024
int numinterpolations = 0, startofdynamicinterpolations = 0;
int oldipos[MAXINTERPOLATIONS];
int bakipos[MAXINTERPOLATIONS];
int *curipos[MAXINTERPOLATIONS];

void setinterpolation(int *posptr)
{
    int i;

    if (numinterpolations >= MAXINTERPOLATIONS)
        return;

    for (i = numinterpolations - 1; i >= 0; i--)
    {
        if (curipos[i] == posptr)
            return;
    }

    curipos[numinterpolations] = posptr;
    oldipos[numinterpolations] = *posptr;
    numinterpolations++;
}

void stopinterpolation(int *posptr)
{
    int i;

    for (i = numinterpolations - 1; i >= startofdynamicinterpolations; i--)
    {
        if (curipos[i] == posptr)
        {
            numinterpolations--;
            oldipos[i] = oldipos[numinterpolations];
            bakipos[i] = bakipos[numinterpolations];
            curipos[i] = curipos[numinterpolations];
        }
    }
}

void updateinterpolations(void)                  // Stick at beginning of domovethings
{
    int i;

    for (i = numinterpolations - 1; i >= 0; i--)
        oldipos[i] = *curipos[i];
}

// must call restore for every do interpolations
// make sure you don't exit
void dointerpolations(int smoothratio)                      // Stick at beginning of drawscreen
{
    int i, j, odelta, ndelta;

    ndelta = 0;
    j = 0;

    for (i = numinterpolations - 1; i >= 0; i--)
    {
        bakipos[i] = *curipos[i];

        odelta = ndelta;
        ndelta = (*curipos[i]) - oldipos[i];

        if (odelta != ndelta)
            j = mulscale16(ndelta, smoothratio);

        *curipos[i] = oldipos[i] + j;
    }
}

void restoreinterpolations(void)                 // Stick at end of drawscreen
{
    int i;

    for (i = numinterpolations - 1; i >= 0; i--)
        *curipos[i] = bakipos[i];
}