123 lines
3.6 KiB
C
123 lines
3.6 KiB
C
/********************************************************************/
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/* STRIPE: converting a polygonal model to triangle strips
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Francine Evans, 1996.
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SUNY @ Stony Brook
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Advisors: Steven Skiena and Amitabh Varshney
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*/
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/********************************************************************/
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/*---------------------------------------------------------------------*/
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/* STRIPE: local.c
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This file contains the code that initializes the data structures for
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the local algorithm, and starts the local algorithm going.
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*/
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/*---------------------------------------------------------------------*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "polverts.h"
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#include "local.h"
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#include "triangulatex.h"
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#include "sturctsex.h"
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#include "common.h"
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#include "outputex.h"
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#include "util.h"
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#include "init.h"
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void Find_StripsEx(FILE *output,FILE *strip,int *ties,
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int tie, int triangulate,
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int swaps,int *next_id)
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{
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/* This routine will peel off the strips from the model */
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ListHead *pListHead;
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P_ADJACENCIES temp = NULL;
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register int max,bucket=0;
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BOOL whole_flag = TRUE;
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int dummy = 0;
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/* Set the last known input edge to be null */
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Last_Edge(&dummy,&dummy,&dummy,1);
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/* Search for lowest adjacency polygon and output strips */
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while (whole_flag)
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{
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bucket = -1;
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/* Search for polygons in increasing number of adjacencies */
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while (bucket < 59)
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{
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bucket++;
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pListHead = array[bucket];
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max = NumOnList(pListHead);
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if (max > 0)
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{
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temp = (P_ADJACENCIES) PeekList(pListHead,LISTHEAD,0);
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if (temp == NULL)
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{
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printf("Error in the buckets%d %d %d\n",bucket,max,0);
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exit(0);
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}
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Polygon_OutputEx(temp,temp->face_id,bucket,pListHead,
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output,strip,ties,tie,triangulate,swaps,next_id,1);
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/* Try to extend backwards, if the starting polygon in the
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strip had 2 or more adjacencies to begin with
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*/
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if (bucket >= 2)
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Extend_BackwardsEx(temp->face_id,output,strip,ties,tie,triangulate,
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swaps,next_id);
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break;
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}
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}
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/* Went through the whole structure, it is empty and we are done.
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*/
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if ((bucket == 59) && (max == 0))
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whole_flag = FALSE;
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/* We just finished a strip, send dummy data to signal the end
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of the strip so that we can output it.
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*/
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else
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{
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Output_TriEx(-1,-2,-3,output,-1,-10,1);
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Last_Edge(&dummy,&dummy,&dummy,1);
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}
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}
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}
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void SGI_Strip(int num_verts,int num_faces,FILE *output,
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int ties,int triangulate)
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{
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FILE *strip;
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int next_id = -1,t=0;
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strip = fopen("output.d","w");
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/* We are going to output and find triangle strips
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according the the method that SGI uses, ie always
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choosing as the next triangle in our strip the triangle
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that has the least number of adjacencies. We do not have
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all triangles and will be triangulating on the fly those
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polygons that have more than 3 sides.
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*/
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/* Build a table that has all the polygons sorted by the number
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of polygons adjacent to it.
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*/
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/* Initialize it */
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Init_Table_SGI();
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/* Build it */
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Build_SGI_Table(num_verts,num_faces);
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/* We will have a structure to hold all the strips, until
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outputted.
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*/
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InitStripTable();
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/* Now we have the structure built to find the polygons according
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to the number of adjacencies. Now use the SGI Method to find
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strips according to the adjacencies
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*/
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Find_StripsEx(output,strip,&t,ties,triangulate,ON,&next_id);
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}
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