/********************************************************************/
/*   STRIPE: converting a polygonal model to triangle strips    
     Francine Evans, 1996.
     SUNY @ Stony Brook
     Advisors: Steven Skiena and Amitabh Varshney
*/
/********************************************************************/

/*---------------------------------------------------------------------*/
/*   STRIPE: local.c
     This file contains the code that initializes the data structures for
     the local algorithm, and starts the local algorithm going.
*/
/*---------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include "polverts.h"
#include "local.h"
#include "triangulatex.h"
#include "sturctsex.h"
#include "common.h"
#include "outputex.h"
#include "util.h"
#include "init.h"

void Find_StripsEx(FILE *output, FILE *strip,int *ties, int tie, 
		   int triangulate, int swaps, int *next_id)
{
	/*	This routine will peel off the strips from the model */

	ListHead *pListHead;
	P_ADJACENCIES temp = NULL;
	register int max,bucket=0;
	BOOL whole_flag = TRUE;
     int dummy = 0;
	
	/* Set the last known input edge to be null */
  Last_Edge(&dummy,&dummy,&dummy,1);
    
  /* Search for lowest adjacency polygon and output strips */
	while (whole_flag)
	{
		bucket = -1;
		/* Search for polygons in increasing number of adjacencies */
		while (bucket < 59)
		{
			bucket++;
			pListHead = array[bucket];
			max = NumOnList(pListHead);
			if (max > 0)
			{
				temp = (P_ADJACENCIES) PeekList(pListHead,LISTHEAD,0);
				if (temp == NULL)
				{
					printf("Error in the buckets%d %d %d\n",bucket,max,0);
					exit(0);
				}
				Polygon_OutputEx(temp,temp->face_id,bucket,pListHead,
	       				       output,strip,ties,tie,triangulate,swaps,next_id,1);
				/* Try to extend backwards, if the starting polygon in the
           strip had 2 or more adjacencies to begin with
        */
        if (bucket >= 2)
          Extend_BackwardsEx(temp->face_id,output,strip,ties,tie,triangulate,swaps,next_id);
        break;  
			}
		}
		/*	Went through the whole structure, it is empty and we are done.
		*/
		if ((bucket == 59) && (max == 0))
			whole_flag = FALSE;
        
    /*  We just finished a strip, send dummy data to signal the end
        of the strip so that we can output it.
    */
    else
    {
      Output_TriEx(-1,-2,-3,output,-1,-10,1);
      Last_Edge(&dummy,&dummy,&dummy,1);
    }
  }
}


void SGI_Strip(int num_verts,int num_faces,FILE *output,
			   int ties,int triangulate)
               
{
	FILE *strip;
  int next_id = -1,t=0;

  strip = fopen("output.d","w");
  /* We are going to output and find triangle strips
   	 according the the method that SGI uses, ie always
		 choosing as the next triangle in our strip the triangle
		 that has the least number of adjacencies. We do not have
		 all triangles and will be triangulating on the fly those
		 polygons that have more than 3 sides.
	*/

	/*	Build a table that has all the polygons sorted by the number
		of polygons adjacent to it.
	*/
	/*	Initialize it */
	Init_Table_SGI();
	/*	Build it */
	Build_SGI_Table(num_verts,num_faces);

	/*    We will have a structure to hold all the strips, until
        outputted.
  */
  InitStripTable();
  /* Now we have the structure built to find the polygons according
		 to the number of adjacencies. Now use the SGI Method to find
		 strips according to the adjacencies
	*/
  Find_StripsEx(output,strip,&t,ties,triangulate,ON,&next_id);
}