/*
 ** BETATRON high level library for platform and action arcade games.
 ** Copyright (C) 1997  Liouros Thanasis, liouros@hotmail.com
 **
 ** GRID.CC: This file is part of the BETATRON library and can be used
 **          and/or distributed only under the terms of the GNU Library
 **          General Public License. See doc/readme.1st for details.
 */



#include "world.h"
#include <stdarg.h>
#include "grid.h"
#include <string.h>

TOobject *Tclustergrid::gridcollision(TOobject *o)
{
  unsigned short x1,y1,x2,y2;
  register unsigned short i,j;
  unsigned short gridstep;
  register TPobjptrlist l;
  register TPobjptrlist *g;

  x1 = o->x >> l2;
  x2 = (o->x+o->slen-1) >> l2;
  y1 = o->y >> h2;
  y2 = (o->y + o->shei -1 ) >> h2;
  gridstep=len-(x2-x1+1);

  g=grid+y1*len+x1;


  for (i=y1;i<=y2;i++,g+=gridstep)
  for (j=x1;j<=x2;j++,g++)
  {
    for (l=(*g);l;l=l->next)
      if (world->collision(l->obj,o)) return l->obj;
  }

  return NULL; // no collision found

}



void Tclustergrid::clusterize()
{
  TOobject *o;
  short i;
  unsigned short x1,y1,x2,y2;
  unsigned short step,k,j;
  TPobjptrlist	*grid0;
  TPobjptrlist	entry;


  // midenise to grid
  memset(grid,0, len*hei*sizeof(TPobjptrlist) );
  if (!listsno) return;
  zerobuffer(); // midenise to buffer


  for (i=0;i<listsno;i++)
  {
   for (o=world->objs[lists[i]];o;o=o->Pnext)
   {

     x1=o->x >> l2;
     x2= (o->x+o->slen-1) >> l2;
     y1=o->y >> h2;
     y2=(o->y+o->shei-1) >> h2;

     step=len - (x2-x1+1);    // poso tha aukisoume to grid0
     grid0=grid+y1*len+x1;

     for (j=y1;j<=y2;j++,grid0+=step)
       for (k=x1;k<=x2;k++,grid0++)
       {
	  if ( !(entry=(TPobjptrlist)getmem(sizeof(Tobjptrlist))) )
	     return; // teleiose i mnimi stamata ti diadikasia

	     // vale to stoixeio stin korifi tis listas
	      entry->obj=o;
	      entry->next= (*grid0);
	      (*grid0)=entry;
       }// for 4
   }//for 2
  }//for 1


}




short Tclustergrid::makegrid(unsigned short length,unsigned short height,TOworld *w)
{

  short s;
  if (grid) return ERR_GRIDMADE;

  // ipologise tis diastaseis tou grid
  len=length >> l2;
  if (length << (16-l2)) len++;
  hei=height >> h2;
  if (height << (16-h2)) hei++;
  // desmeuse mnimi gia to buffer
  if (s=initbuffer(maxobjsno*sizeof(Tobjptrlist)) ) return s;
  // desmeuse mnimi gia to grid kai to grid indexes
  if ( !(grid=(TPobjptrlist *) malloc(len*hei*sizeof(TPobjptrlist)))  )
  {
   freebuffer();
   return ERR_OUTOFMEM;
  }

  world=w;
  return ERR_NOERR;
}



void  *Tclustergrid::getmem(unsigned short size0)
{
 void *res;

 if ( (!size0)	|| (nowpos+size0>bufsize) ) return NULL;
 res=(void *)(data + nowpos);
 nowpos+=size0;
 return res;
}


short Tclustergrid::initbuffer(long size0)
{
 if (!size0) return ERR_ZEROMEMALLOC;
 if (! (data=(char *)malloc(size0)) ) return ERR_OUTOFMEM;

 bufsize=size0;
 nowpos=0;
 return ERR_NOERR;
}

void Tclustergrid::freebuffer()
{
 free(data);
 bufsize=0;
 nowpos=0;
 data=NULL;
}





// constructor
Tclustergrid::Tclustergrid()
{
   bufsize=0;
   nowpos=0;
   data=NULL;
   element=NULL;

   l2=DEFCELLL;
   h2=DEFCELLH;
   maxobjsno=DEFMAXOBJSNO;

   grid=NULL;
   listsno=0;
}







short Tclustergrid::setparameters(unsigned char l20,unsigned char h20,
				  unsigned short maxobjsno0)
{

  if (grid) return ERR_GRIDMADE;

  if (	 l20	     >	MAXGRIDCELLL
      || h20	     >	MAXGRIDCELLH
      || maxobjsno0 >	MAXMAXOBJSNO) return ERR_OUTOFRANGE;

      l2=l20;
      h2=h20;
      maxobjsno=maxobjsno0;

  return ERR_NOERR;
}



short Tclustergrid::addfirstlist(short list)
{
 listsno=0;
 return addlist(list);
}

short Tclustergrid::addlist(short list)
{
 if (listsno>=MAXLISTS) return ERR_TOOMANYLISTS;
 lists[listsno++]=list;
 return ERR_NOERR;
}


Tclustergrid::~Tclustergrid()
{
 done();
}


void Tclustergrid::done()
{
 freebuffer();
 free(grid);
 grid=NULL;
 listsno=0;
 element=NULL;
}