124 lines
3.6 KiB
C
124 lines
3.6 KiB
C
|
/********************************************************************/
|
||
|
|
/* 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);
|
||
|
|
|
||
|
|
}
|