1 |
/* Copyright (c) 1998 Silicon Graphics, Inc. */ |
2 |
|
3 |
#ifndef lint |
4 |
static char SCCSid[] = "$SunId$ SGI"; |
5 |
#endif |
6 |
|
7 |
/* |
8 |
* sm_del.c |
9 |
*/ |
10 |
#include "standard.h" |
11 |
#include "sm_flag.h" |
12 |
#include "sm_list.h" |
13 |
#include "sm_geom.h" |
14 |
#include "sm_qtree.h" |
15 |
#include "sm_stree.h" |
16 |
#include "sm.h" |
17 |
|
18 |
static int Max_edges=200; |
19 |
static EDGE *Edges=NULL; |
20 |
static int Ecnt=0; |
21 |
|
22 |
smFree_tri(sm,id) |
23 |
SM *sm; |
24 |
int id; |
25 |
{ |
26 |
TRI *tri,*t; |
27 |
|
28 |
tri = SM_NTH_TRI(sm,id); |
29 |
/* Add to the free_list */ |
30 |
|
31 |
T_NEXT_FREE(tri) = SM_FREE_TRIS(sm); |
32 |
SM_FREE_TRIS(sm) = id; |
33 |
T_VALID_FLAG(tri) = -1; |
34 |
} |
35 |
|
36 |
/* Assumes mesh pointers have been cleaned up appropriately: just deletes from |
37 |
Point location and triangle data structure |
38 |
*/ |
39 |
smDelete_tri(sm,t_id) |
40 |
SM *sm; |
41 |
int t_id; |
42 |
{ |
43 |
|
44 |
/* NOTE: Assumes that a new triangle adjacent to each vertex |
45 |
has been added- before the deletion: replacing |
46 |
the old tri- and therefore dont need to dereference any pointers |
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to id because the vertices can no longer |
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point to tri id as being the first triangle pointer |
49 |
*/ |
50 |
if(!SM_IS_NTH_T_BASE(sm,t_id)) |
51 |
{ |
52 |
SM_SAMPLE_TRIS(sm)--; |
53 |
if(SM_IS_NTH_T_NEW(sm,t_id)) |
54 |
smNew_tri_cnt--; |
55 |
} |
56 |
smClear_tri_flags(sm,t_id); |
57 |
|
58 |
smFree_tri(sm,t_id); |
59 |
|
60 |
#if 0 |
61 |
{ |
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int i; |
63 |
TRI *t; |
64 |
for(i=0; i < SM_NUM_TRI(sm);i++) |
65 |
{ |
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t = SM_NTH_TRI(sm,i); |
67 |
if(!T_IS_VALID(t)) |
68 |
continue; |
69 |
if(T_NTH_NBR(t,0)==t_id || T_NTH_NBR(t,1)==t_id || T_NTH_NBR(t,2)==t_id) |
70 |
eputs("Stale pointer: smDelete_tri()\n"); |
71 |
} |
72 |
} |
73 |
#endif |
74 |
} |
75 |
|
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|
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int |
78 |
eNew_edge() |
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{ |
80 |
if(!Edges) |
81 |
if(!(Edges = (EDGE *)realloc(NULL,(Max_edges+1)*sizeof(EDGE)))) |
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goto memerr; |
83 |
|
84 |
if(Ecnt >= Max_edges) |
85 |
{ |
86 |
if(Max_edges > 10000) |
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error(CONSISTENCY,"Too many edges in vertex loop\n"); |
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Max_edges += 100; |
89 |
if(!(Edges = (EDGE *)realloc(Edges,(Max_edges+1)*sizeof(EDGE)))) |
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goto memerr; |
91 |
} |
92 |
return(++Ecnt); |
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|
94 |
memerr: |
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error(SYSTEM,"eNew_edge(): Unable to allocate memory"); |
96 |
} |
97 |
|
98 |
/* Return list of edges defining polygon formed by boundary of triangles |
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adjacent to id. Return set of triangles adjacent to id to delete in delptr |
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*/ |
101 |
LIST |
102 |
*smVertexPolygon(sm,id,del_ptr) |
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SM *sm; |
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int id; |
105 |
LIST **del_ptr; |
106 |
{ |
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TRI *tri,*t_next; |
108 |
LIST *elist,*end; |
109 |
int e,t_id,v_next,t_next_id,b_id,v_id; |
110 |
|
111 |
eClear_edges(); |
112 |
elist = end = NULL; |
113 |
|
114 |
/* Get the first triangle adjacent to vertex id */ |
115 |
t_id = SM_NTH_VERT(sm,id); |
116 |
tri = SM_NTH_TRI(sm,t_id); |
117 |
|
118 |
e = eNew_edge(); |
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/* Get the next vertex on the polygon boundary */ |
120 |
v_id = T_WHICH_V(tri,id); |
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b_id = (v_id + 1)%3; |
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/* Create an edge */ |
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SET_E_NTH_VERT(e,0,T_NTH_V(tri,b_id)); |
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SET_E_NTH_TRI(e,0,INVALID); |
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SET_E_NTH_TRI(e,1,T_NTH_NBR(tri,v_id)); |
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v_next = T_NTH_V(tri,(b_id+1)%3); |
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SET_E_NTH_VERT(e,1,v_next); |
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elist = add_data_to_circular_list(elist,&end,e); |
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t_next_id = t_id; |
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t_next = tri; |
131 |
|
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*del_ptr = push_data(*del_ptr,t_id); |
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/* Create a set to hold all of the triangles for deletion later */ |
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|
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while((t_next_id = T_NTH_NBR(t_next,b_id)) != t_id) |
136 |
{ |
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e = eNew_edge(); |
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t_next = SM_NTH_TRI(sm,t_next_id); |
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SET_E_NTH_VERT(e,0,v_next); |
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SET_E_NTH_TRI(e,0,INVALID); |
141 |
v_id = T_WHICH_V(t_next,id); |
142 |
b_id = (v_id + 1)%3; |
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SET_E_NTH_TRI(e,1,T_NTH_NBR(t_next,v_id)); |
144 |
v_next = T_NTH_V(t_next,(b_id+1)%3); |
145 |
SET_E_NTH_VERT(e,1,v_next); |
146 |
elist = add_data_to_circular_list(elist,&end,e); |
147 |
*del_ptr = push_data(*del_ptr,t_next_id); |
148 |
} |
149 |
return(elist); |
150 |
} |
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|
152 |
|
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int |
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smTriangulate_add_tri(sm,id0,id1,id2,e0,e1,e2ptr) |
155 |
SM *sm; |
156 |
int id0,id1,id2,e0,e1,*e2ptr; |
157 |
{ |
158 |
int t_id; |
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int e2; |
160 |
|
161 |
#ifdef DEBUG |
162 |
if(id0 == INVALID || id1==INVALID || id2==INVALID) |
163 |
error(CONSISTENCY,"bad id- smTriangulate_add_tri()\n"); |
164 |
#endif |
165 |
t_id = smAdd_tri(sm,id0,id1,id2); |
166 |
if(*e2ptr == 0) |
167 |
{ |
168 |
e2 = eNew_edge(); |
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SET_E_NTH_VERT(e2,0,id2); |
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SET_E_NTH_VERT(e2,1,id0); |
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} |
172 |
else |
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e2 = *e2ptr; |
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/* set appropriate tri for each edge*/ |
175 |
SET_E_NTH_TRI(e0,0,t_id); |
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SET_E_NTH_TRI(e1,0,t_id); |
177 |
SET_E_NTH_TRI(e2,0,t_id); |
178 |
|
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*e2ptr = e2; |
180 |
return(t_id); |
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} |
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|
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int |
184 |
smTriangulateConvex(sm,plist,add_ptr) |
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SM *sm; |
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LIST *plist,**add_ptr; |
187 |
{ |
188 |
int t_id,e_id0,e_id1,e_id2; |
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int v_id0,v_id1,v_id2; |
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LIST *lptr; |
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|
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lptr = plist; |
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e_id0 = (int)LIST_DATA(lptr); |
194 |
v_id0 = E_NTH_VERT(e_id0,0); |
195 |
lptr = LIST_NEXT(lptr); |
196 |
while(LIST_NEXT(lptr) != plist) |
197 |
{ |
198 |
e_id1 = (int)LIST_DATA(lptr); |
199 |
v_id1 = E_NTH_VERT(e_id1,0); |
200 |
v_id2 = E_NTH_VERT(e_id1,1); |
201 |
lptr = LIST_NEXT(lptr); |
202 |
|
203 |
if(LIST_NEXT(lptr) != plist) |
204 |
e_id2 = 0; |
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else |
206 |
e_id2 = (int)LIST_DATA(lptr); |
207 |
t_id = smTriangulate_add_tri(sm,v_id0,v_id1,v_id2,e_id0,e_id1,&e_id2); |
208 |
*add_ptr = push_data(*add_ptr,t_id); |
209 |
e_id0 = -e_id2; |
210 |
} |
211 |
free_list(plist); |
212 |
return(TRUE); |
213 |
} |
214 |
#ifdef TEST_DRIVER |
215 |
FVECT Norm[500],B_V[500]; |
216 |
int Ncnt,Bcnt,Del=0; |
217 |
#endif |
218 |
|
219 |
|
220 |
/* Triangulate the polygon defined by plist, and generating vertex p_id. |
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Return list of added triangles in list add_ptr. Returns TRUE if |
222 |
successful, FALSE otherwise. This is NOT a general triangulation routine, |
223 |
assumes polygon star relative to id |
224 |
*/ |
225 |
|
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int |
227 |
smTriangulate(sm,id,plist,add_ptr) |
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SM *sm; |
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int id; |
230 |
LIST *plist,**add_ptr; |
231 |
{ |
232 |
LIST *l,*prev,*t; |
233 |
FVECT v0,v1,v2,n,p; |
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int is_tri,is_convex,cut,t_id,id0,id1,id2,e2,e1,enew; |
235 |
double dp; |
236 |
static int debug=0; |
237 |
|
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VSUB(p,SM_NTH_WV(sm,id),SM_VIEW_CENTER(sm)); |
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enew = 0; |
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is_convex = TRUE; |
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cut = is_tri= FALSE; |
242 |
l = prev = plist; |
243 |
|
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/* get v0,v1 */ |
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e1 = (int)LIST_DATA(l); |
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id0 = E_NTH_VERT(e1,0); |
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id1 = E_NTH_VERT(e1,1); |
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VSUB(v0,SM_NTH_WV(sm,id0),SM_VIEW_CENTER(sm)); |
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VSUB(v1,SM_NTH_WV(sm,id1),SM_VIEW_CENTER(sm)); |
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#ifdef TEST_DRIVER |
251 |
Del = TRUE; |
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VCOPY(B_V[0],v0); |
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VCOPY(B_V[1],v1); |
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Bcnt = 2; |
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Ncnt = 0; |
256 |
#endif |
257 |
while(l) |
258 |
{ |
259 |
l = LIST_NEXT(l); |
260 |
/* Get v2 */ |
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e2 = (int)LIST_DATA(l); |
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id2 = E_NTH_VERT(e2,1); |
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VSUB(v2,SM_NTH_WV(sm,id2),SM_VIEW_CENTER(sm)); |
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#ifdef TEST_DRIVER |
265 |
VCOPY(B_V[Bcnt++],v2); |
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#endif |
267 |
if(LIST_NEXT(LIST_NEXT(l)) == prev) |
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{/* Check if have a triangle */ |
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is_tri = TRUE; |
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break; |
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} |
272 |
|
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/* determine if v0-v1-v2 is convex:defined clockwise on the sphere- |
274 |
so switch orientation |
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*/ |
276 |
if(convex_angle(v2,v1,v0)) |
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{ |
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/* test if safe to cut off v0-v1-v2 by testing if p lies outside of |
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triangle v0-v1-v2: if so, because plist is the star polygon around p, |
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the new edge v2-v0 cannot intersect any existing edges |
281 |
*/ |
282 |
VCROSS(n,v0,v2); |
283 |
dp = DOT(n,p); |
284 |
if(dp <= 0.0) |
285 |
{ |
286 |
/* remove edges e1,e2 and add triangle id0,id1,id2 */ |
287 |
enew = 0; |
288 |
t_id = smTriangulate_add_tri(sm,id0,id1,id2,e1,e2,&enew); |
289 |
cut = TRUE; |
290 |
*add_ptr = push_data(*add_ptr,t_id); |
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/* Insert edge enew into the list, reuse prev list element */ |
292 |
LIST_NEXT(prev) = LIST_NEXT(l); |
293 |
LIST_DATA(prev) = e1 = -enew; |
294 |
/* If removing head of list- reset plist pointer */ |
295 |
if(l== plist) |
296 |
plist = prev; |
297 |
/* free list element for e2 */ |
298 |
LIST_NEXT(l)=NULL; |
299 |
free_list(l); |
300 |
l = prev; |
301 |
VCOPY(v1,v2); |
302 |
id1 = id2; |
303 |
continue; |
304 |
} |
305 |
} |
306 |
else |
307 |
is_convex = FALSE; |
308 |
VCOPY(v0,v1); |
309 |
VCOPY(v1,v2); |
310 |
id0 = id1; |
311 |
id1 = id2; |
312 |
e1 = e2; |
313 |
/* check if gone around circular list without adding any |
314 |
triangles: prevent infinite loop */ |
315 |
if(l == plist) |
316 |
{ |
317 |
if(LIST_NEXT(LIST_NEXT(l)) == prev) |
318 |
{/* Check if have a triangle */ |
319 |
is_tri = TRUE; |
320 |
break; |
321 |
} |
322 |
|
323 |
if(is_convex) |
324 |
break; |
325 |
if(!cut) |
326 |
{ |
327 |
#ifdef DEBUG |
328 |
eputs("smTriangulate():Unable to triangulate\n"); |
329 |
#endif |
330 |
free_list(l); |
331 |
while(*add_ptr) |
332 |
{ |
333 |
t_id = pop_list(add_ptr); |
334 |
smDelete_tri(sm,t_id); |
335 |
} |
336 |
return(FALSE); |
337 |
} |
338 |
|
339 |
cut = FALSE; |
340 |
is_convex = TRUE; |
341 |
} |
342 |
prev = l; |
343 |
} |
344 |
if(is_tri) |
345 |
{ |
346 |
l = LIST_NEXT(l); |
347 |
enew = (int)LIST_DATA(l); |
348 |
t_id = smTriangulate_add_tri(sm,id0,id1,id2,e1,e2,&enew); |
349 |
*add_ptr = push_data(*add_ptr,t_id); |
350 |
free_list(l); |
351 |
} |
352 |
else |
353 |
if(!smTriangulateConvex(sm,l,add_ptr)) |
354 |
return(FALSE); |
355 |
|
356 |
/* Set triangle adjacencies based on edge adjacencies */ |
357 |
FOR_ALL_EDGES(enew) |
358 |
{ |
359 |
id0 = E_NTH_TRI(enew,0); |
360 |
id1 = E_NTH_TRI(enew,1); |
361 |
|
362 |
e1 = (T_WHICH_V(SM_NTH_TRI(sm,id0),E_NTH_VERT(enew,0))+2)%3; |
363 |
T_NTH_NBR(SM_NTH_TRI(sm,id0),e1) = id1; |
364 |
|
365 |
e2 = (T_WHICH_V(SM_NTH_TRI(sm,id1),E_NTH_VERT(enew,1))+2)%3; |
366 |
T_NTH_NBR(SM_NTH_TRI(sm,id1),e2) = id0; |
367 |
} |
368 |
return(TRUE); |
369 |
} |
370 |
|
371 |
eIn_tri(e,t) |
372 |
int e; |
373 |
TRI *t; |
374 |
{ |
375 |
|
376 |
if(T_NTH_V(t,0)==E_NTH_VERT(e,0)) |
377 |
return(T_NTH_V(t,1)==E_NTH_VERT(e,1)||T_NTH_V(t,2)==E_NTH_VERT(e,1)); |
378 |
else |
379 |
if(T_NTH_V(t,1)==E_NTH_VERT(e,0)) |
380 |
return(T_NTH_V(t,0)==E_NTH_VERT(e,1)||T_NTH_V(t,2)==E_NTH_VERT(e,1)); |
381 |
else if(T_NTH_V(t,2)==E_NTH_VERT(e,0)) |
382 |
return(T_NTH_V(t,0)==E_NTH_VERT(e,1)||T_NTH_V(t,1)==E_NTH_VERT(e,1)); |
383 |
|
384 |
return(FALSE); |
385 |
} |
386 |
|
387 |
/* Test the new set of triangles for Delaunay condition. 'Edges' contains |
388 |
all of the new edges added. The CCW triangle assoc with each edge is |
389 |
tested against the opposite vertex of the CW triangle. If the vertex |
390 |
lies inside the circle defined by the CCW triangle- the edge is swapped |
391 |
for the opposite diagonal |
392 |
*/ |
393 |
smFixEdges(sm,add_list) |
394 |
SM *sm; |
395 |
LIST *add_list; |
396 |
{ |
397 |
int e,t0_id,t1_id,e_new,e0,e1,e0_next,e1_next; |
398 |
int i,v0_id,v1_id,v2_id,p_id,t0_nid,t1_nid; |
399 |
FVECT v0,v1,v2,p,np,v; |
400 |
TRI *t0,*t1; |
401 |
|
402 |
FOR_ALL_EDGES(e) |
403 |
{ |
404 |
t0_id = E_NTH_TRI(e,0); |
405 |
t1_id = E_NTH_TRI(e,1); |
406 |
if((t0_id==INVALID) || (t1_id==INVALID)) |
407 |
{ |
408 |
#ifdef DEBUG |
409 |
error(CONSISTENCY,"smFix_edges: Unassigned edge nbr\n"); |
410 |
#endif |
411 |
} |
412 |
t0 = SM_NTH_TRI(sm,t0_id); |
413 |
t1 = SM_NTH_TRI(sm,t1_id); |
414 |
e0 = T_NTH_NBR_PTR(t1_id,t0); |
415 |
e1 = T_NTH_NBR_PTR(t0_id,t1); |
416 |
|
417 |
v0_id = E_NTH_VERT(e,0); |
418 |
v1_id = E_NTH_VERT(e,1); |
419 |
v2_id = T_NTH_V(t0,e0); |
420 |
p_id = T_NTH_V(t1,e1); |
421 |
|
422 |
smDir_in_cone(sm,v0,v0_id); |
423 |
smDir_in_cone(sm,v1,v1_id); |
424 |
smDir_in_cone(sm,v2,v2_id); |
425 |
|
426 |
VCOPY(p,SM_NTH_WV(sm,p_id)); |
427 |
VSUB(p,p,SM_VIEW_CENTER(sm)); |
428 |
if(point_in_cone(p,v0,v1,v2)) |
429 |
{ |
430 |
smTris_swap_edge(sm,t0_id,t1_id,e0,e1,&t0_nid,&t1_nid,&add_list); |
431 |
|
432 |
/* Adjust the triangle pointers of the remaining edges to be |
433 |
processed |
434 |
*/ |
435 |
FOR_ALL_EDGES_FROM(e,i) |
436 |
{ |
437 |
if(E_NTH_TRI(i,0)==t0_id || E_NTH_TRI(i,0)==t1_id) |
438 |
{ |
439 |
if(eIn_tri(i,SM_NTH_TRI(sm,t0_nid))) |
440 |
SET_E_NTH_TRI(i,0,t0_nid); |
441 |
else |
442 |
SET_E_NTH_TRI(i,0,t1_nid); |
443 |
} |
444 |
|
445 |
if(E_NTH_TRI(i,1)==t0_id || E_NTH_TRI(i,1)==t1_id) |
446 |
{ |
447 |
if(eIn_tri(i,SM_NTH_TRI(sm,t0_nid))) |
448 |
SET_E_NTH_TRI(i,1,t0_nid); |
449 |
else |
450 |
SET_E_NTH_TRI(i,1,t1_nid); |
451 |
} |
452 |
} |
453 |
t0_id = t0_nid; |
454 |
t1_id = t1_nid; |
455 |
e_new = eNew_edge(); |
456 |
SET_E_NTH_VERT(e_new,0,p_id); |
457 |
SET_E_NTH_VERT(e_new,1,v2_id); |
458 |
SET_E_NTH_TRI(e_new,0,t0_id); |
459 |
SET_E_NTH_TRI(e_new,1,t1_id); |
460 |
} |
461 |
} |
462 |
/* Add/Delete the appropriate triangles from the stree */ |
463 |
smUpdate_locator(sm,add_list); |
464 |
} |
465 |
|
466 |
/* Remove vertex "id" from the mesh- and retriangulate the resulting |
467 |
hole: Returns TRUE if successful, FALSE otherwise. |
468 |
*/ |
469 |
int |
470 |
smRemoveVertex(sm,id) |
471 |
SM *sm; |
472 |
int id; |
473 |
{ |
474 |
LIST *b_list,*add_list,*del_list; |
475 |
int t_id,i; |
476 |
static int cnt=0; |
477 |
OBJECT *optr,*os; |
478 |
/* generate list of edges that form the boundary of the |
479 |
polygon formed by the triangles adjacent to vertex 'id' |
480 |
*/ |
481 |
del_list = NULL; |
482 |
b_list = smVertexPolygon(sm,id,&del_list); |
483 |
|
484 |
add_list = NULL; |
485 |
/* Triangulate polygonal hole */ |
486 |
if(!smTriangulate(sm,id,b_list,&add_list)) |
487 |
{ |
488 |
free_list(del_list); |
489 |
return(FALSE); |
490 |
} |
491 |
else |
492 |
{ |
493 |
#ifdef DEBUG |
494 |
b_list = del_list; |
495 |
while(b_list) |
496 |
{ |
497 |
t_id = LIST_DATA(b_list); |
498 |
b_list = LIST_NEXT(b_list); |
499 |
T_VALID_FLAG(SM_NTH_TRI(sm,t_id))=-1; |
500 |
} |
501 |
#endif |
502 |
while(del_list) |
503 |
{ |
504 |
t_id = pop_list(&del_list); |
505 |
smDelete_tri(sm,t_id); |
506 |
} |
507 |
} |
508 |
/* Fix up new triangles to be Delaunay-delnode contains set of |
509 |
triangles to delete,add_list is the set of new triangles to add |
510 |
*/ |
511 |
smFixEdges(sm,add_list); |
512 |
|
513 |
return(TRUE); |
514 |
} |
515 |
|
516 |
|
517 |
|
518 |
|
519 |
|
520 |
|
521 |
|
522 |
|
523 |
|
524 |
|
525 |
|
526 |
|
527 |
|
528 |
|
529 |
|