| 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 |
smClear_tri_flags(sm,id); |
| 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 |
| 47 |
to id because the vertices can no longer |
| 48 |
point to tri id as being the first triangle pointer |
| 49 |
*/ |
| 50 |
SM_SAMPLE_TRIS(sm)--; |
| 51 |
if(SM_IS_NTH_T_NEW(sm,t_id)) |
| 52 |
smNew_tri_cnt--; |
| 53 |
|
| 54 |
smClear_tri_flags(sm,t_id); |
| 55 |
|
| 56 |
smFree_tri(sm,t_id); |
| 57 |
} |
| 58 |
|
| 59 |
|
| 60 |
int |
| 61 |
eNew_edge() |
| 62 |
{ |
| 63 |
if(!Edges) |
| 64 |
if(!(Edges = (EDGE *)realloc(NULL,(Max_edges+1)*sizeof(EDGE)))) |
| 65 |
goto memerr; |
| 66 |
|
| 67 |
if(Ecnt >= Max_edges) |
| 68 |
{ |
| 69 |
if(Max_edges > 10000) |
| 70 |
{ |
| 71 |
eputs("Too many edges in vertex loop\n"); |
| 72 |
return(-1); |
| 73 |
} |
| 74 |
Max_edges += 100; |
| 75 |
if(!(Edges = (EDGE *)realloc(Edges,(Max_edges+1)*sizeof(EDGE)))) |
| 76 |
goto memerr; |
| 77 |
} |
| 78 |
return(++Ecnt); |
| 79 |
|
| 80 |
memerr: |
| 81 |
error(SYSTEM,"eNew_edge(): Unable to allocate memory"); |
| 82 |
} |
| 83 |
|
| 84 |
/* Return list of edges defining polygon formed by boundary of triangles |
| 85 |
adjacent to id. Return set of triangles adjacent to id to delete in delptr |
| 86 |
*/ |
| 87 |
LIST |
| 88 |
*smVertexStar(sm,id,del_ptr) |
| 89 |
SM *sm; |
| 90 |
int id; |
| 91 |
LIST **del_ptr; |
| 92 |
{ |
| 93 |
TRI *tri,*t_next; |
| 94 |
LIST *elist,*end; |
| 95 |
int e,t_id,v_next,t_next_id,b_id,v_id; |
| 96 |
|
| 97 |
eClear_edges(); |
| 98 |
elist = end = NULL; |
| 99 |
|
| 100 |
/* Get the first triangle adjacent to vertex id */ |
| 101 |
t_id = SM_NTH_VERT(sm,id); |
| 102 |
tri = SM_NTH_TRI(sm,t_id); |
| 103 |
|
| 104 |
e = eNew_edge(); |
| 105 |
|
| 106 |
/* Get the next vertex on the polygon boundary */ |
| 107 |
v_id = T_WHICH_V(tri,id); |
| 108 |
b_id = (v_id + 1)%3; |
| 109 |
/* Create an edge */ |
| 110 |
SET_E_NTH_VERT(e,0,T_NTH_V(tri,b_id)); |
| 111 |
SET_E_NTH_TRI(e,0,INVALID); |
| 112 |
SET_E_NTH_TRI(e,1,T_NTH_NBR(tri,v_id)); |
| 113 |
v_next = T_NTH_V(tri,(b_id+1)%3); |
| 114 |
SET_E_NTH_VERT(e,1,v_next); |
| 115 |
elist = add_data_to_circular_list(elist,&end,e); |
| 116 |
t_next_id = t_id; |
| 117 |
t_next = tri; |
| 118 |
|
| 119 |
*del_ptr = push_data(*del_ptr,t_id); |
| 120 |
/* Create a set to hold all of the triangles for deletion later */ |
| 121 |
|
| 122 |
while((t_next_id = T_NTH_NBR(t_next,b_id)) != t_id) |
| 123 |
{ |
| 124 |
e = eNew_edge(); |
| 125 |
if(e== INVALID) |
| 126 |
return(NULL); |
| 127 |
t_next = SM_NTH_TRI(sm,t_next_id); |
| 128 |
SET_E_NTH_VERT(e,0,v_next); |
| 129 |
SET_E_NTH_TRI(e,0,INVALID); |
| 130 |
v_id = T_WHICH_V(t_next,id); |
| 131 |
b_id = (v_id + 1)%3; |
| 132 |
SET_E_NTH_TRI(e,1,T_NTH_NBR(t_next,v_id)); |
| 133 |
v_next = T_NTH_V(t_next,(b_id+1)%3); |
| 134 |
SET_E_NTH_VERT(e,1,v_next); |
| 135 |
elist = add_data_to_circular_list(elist,&end,e); |
| 136 |
*del_ptr = push_data(*del_ptr,t_next_id); |
| 137 |
} |
| 138 |
return(elist); |
| 139 |
} |
| 140 |
|
| 141 |
|
| 142 |
int |
| 143 |
smTriangulate_add_tri(sm,id0,id1,id2,e0,e1,e2ptr) |
| 144 |
SM *sm; |
| 145 |
int id0,id1,id2,e0,e1,*e2ptr; |
| 146 |
{ |
| 147 |
int t_id; |
| 148 |
int e2; |
| 149 |
|
| 150 |
#ifdef DEBUG |
| 151 |
if(id0 == INVALID || id1==INVALID || id2==INVALID) |
| 152 |
error(CONSISTENCY,"bad id- smTriangulate_add_tri()\n"); |
| 153 |
#endif |
| 154 |
t_id = smAdd_tri(sm,id0,id1,id2); |
| 155 |
if(*e2ptr == 0) |
| 156 |
{ |
| 157 |
e2 = eNew_edge(); |
| 158 |
SET_E_NTH_VERT(e2,0,id2); |
| 159 |
SET_E_NTH_VERT(e2,1,id0); |
| 160 |
} |
| 161 |
else |
| 162 |
e2 = *e2ptr; |
| 163 |
/* set appropriate tri for each edge*/ |
| 164 |
SET_E_NTH_TRI(e0,0,t_id); |
| 165 |
SET_E_NTH_TRI(e1,0,t_id); |
| 166 |
SET_E_NTH_TRI(e2,0,t_id); |
| 167 |
|
| 168 |
*e2ptr = e2; |
| 169 |
return(t_id); |
| 170 |
} |
| 171 |
|
| 172 |
int |
| 173 |
smTriangulateConvex(sm,plist,add_ptr) |
| 174 |
SM *sm; |
| 175 |
LIST *plist,**add_ptr; |
| 176 |
{ |
| 177 |
int t_id,e_id0,e_id1,e_id2; |
| 178 |
int v_id0,v_id1,v_id2; |
| 179 |
LIST *lptr; |
| 180 |
|
| 181 |
lptr = plist; |
| 182 |
e_id0 = (int)LIST_DATA(lptr); |
| 183 |
v_id0 = E_NTH_VERT(e_id0,0); |
| 184 |
lptr = LIST_NEXT(lptr); |
| 185 |
while(LIST_NEXT(lptr) != plist) |
| 186 |
{ |
| 187 |
e_id1 = (int)LIST_DATA(lptr); |
| 188 |
v_id1 = E_NTH_VERT(e_id1,0); |
| 189 |
v_id2 = E_NTH_VERT(e_id1,1); |
| 190 |
lptr = LIST_NEXT(lptr); |
| 191 |
|
| 192 |
if(LIST_NEXT(lptr) != plist) |
| 193 |
e_id2 = 0; |
| 194 |
else |
| 195 |
e_id2 = (int)LIST_DATA(lptr); |
| 196 |
t_id = smTriangulate_add_tri(sm,v_id0,v_id1,v_id2,e_id0,e_id1,&e_id2); |
| 197 |
*add_ptr = push_data(*add_ptr,t_id); |
| 198 |
e_id0 = -e_id2; |
| 199 |
} |
| 200 |
free_list(plist); |
| 201 |
return(TRUE); |
| 202 |
} |
| 203 |
#ifdef TEST_DRIVER |
| 204 |
FVECT Norm[500],B_V[500]; |
| 205 |
int Ncnt,Bcnt,Del=0; |
| 206 |
#endif |
| 207 |
|
| 208 |
|
| 209 |
/* Triangulate the polygon defined by plist, and generating vertex p_id. |
| 210 |
Return list of added triangles in list add_ptr. Returns TRUE if |
| 211 |
successful, FALSE otherwise. This is NOT a general triangulation routine, |
| 212 |
assumes polygon star relative to id |
| 213 |
*/ |
| 214 |
|
| 215 |
int |
| 216 |
smTriangulate(sm,id,plist,add_ptr) |
| 217 |
SM *sm; |
| 218 |
int id; |
| 219 |
LIST *plist,**add_ptr; |
| 220 |
{ |
| 221 |
LIST *l,*prev,*t; |
| 222 |
FVECT v0,v1,v2,n,p; |
| 223 |
int is_tri,is_convex,cut,t_id,id0,id1,id2,e2,e1,enew; |
| 224 |
double dp; |
| 225 |
static int debug=0; |
| 226 |
|
| 227 |
VSUB(p,SM_NTH_WV(sm,id),SM_VIEW_CENTER(sm)); |
| 228 |
enew = 0; |
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is_convex = TRUE; |
| 230 |
cut = is_tri= FALSE; |
| 231 |
l = prev = plist; |
| 232 |
|
| 233 |
/* get v0,v1 */ |
| 234 |
e1 = (int)LIST_DATA(l); |
| 235 |
id0 = E_NTH_VERT(e1,0); |
| 236 |
id1 = E_NTH_VERT(e1,1); |
| 237 |
VSUB(v0,SM_NTH_WV(sm,id0),SM_VIEW_CENTER(sm)); |
| 238 |
VSUB(v1,SM_NTH_WV(sm,id1),SM_VIEW_CENTER(sm)); |
| 239 |
#ifdef TEST_DRIVER |
| 240 |
Del = TRUE; |
| 241 |
VCOPY(B_V[0],v0); |
| 242 |
VCOPY(B_V[1],v1); |
| 243 |
Bcnt = 2; |
| 244 |
Ncnt = 0; |
| 245 |
#endif |
| 246 |
while(l) |
| 247 |
{ |
| 248 |
l = LIST_NEXT(l); |
| 249 |
/* Get v2 */ |
| 250 |
e2 = (int)LIST_DATA(l); |
| 251 |
id2 = E_NTH_VERT(e2,1); |
| 252 |
VSUB(v2,SM_NTH_WV(sm,id2),SM_VIEW_CENTER(sm)); |
| 253 |
#ifdef TEST_DRIVER |
| 254 |
VCOPY(B_V[Bcnt++],v2); |
| 255 |
#endif |
| 256 |
if(LIST_NEXT(LIST_NEXT(l)) == prev) |
| 257 |
{/* Check if have a triangle */ |
| 258 |
is_tri = TRUE; |
| 259 |
break; |
| 260 |
} |
| 261 |
|
| 262 |
/* determine if v0-v1-v2 is convex:defined clockwise on the sphere- |
| 263 |
so switch orientation |
| 264 |
*/ |
| 265 |
if(convex_angle(v2,v1,v0)) |
| 266 |
{ |
| 267 |
/* test if safe to cut off v0-v1-v2 by testing if p lies outside of |
| 268 |
triangle v0-v1-v2: if so, because plist is the star polygon around p, |
| 269 |
the new edge v2-v0 cannot intersect any existing edges |
| 270 |
*/ |
| 271 |
VCROSS(n,v0,v2); |
| 272 |
dp = DOT(n,p); |
| 273 |
if(dp <= 0.0) |
| 274 |
{ |
| 275 |
/* remove edges e1,e2 and add triangle id0,id1,id2 */ |
| 276 |
enew = 0; |
| 277 |
t_id = smTriangulate_add_tri(sm,id0,id1,id2,e1,e2,&enew); |
| 278 |
cut = TRUE; |
| 279 |
*add_ptr = push_data(*add_ptr,t_id); |
| 280 |
/* Insert edge enew into the list, reuse prev list element */ |
| 281 |
LIST_NEXT(prev) = LIST_NEXT(l); |
| 282 |
LIST_DATA(prev) = e1 = -enew; |
| 283 |
/* If removing head of list- reset plist pointer */ |
| 284 |
if(l== plist) |
| 285 |
plist = prev; |
| 286 |
/* free list element for e2 */ |
| 287 |
LIST_NEXT(l)=NULL; |
| 288 |
free_list(l); |
| 289 |
l = prev; |
| 290 |
VCOPY(v1,v2); |
| 291 |
id1 = id2; |
| 292 |
continue; |
| 293 |
} |
| 294 |
} |
| 295 |
else |
| 296 |
is_convex = FALSE; |
| 297 |
VCOPY(v0,v1); |
| 298 |
VCOPY(v1,v2); |
| 299 |
id0 = id1; |
| 300 |
id1 = id2; |
| 301 |
e1 = e2; |
| 302 |
/* check if gone around circular list without adding any |
| 303 |
triangles: prevent infinite loop */ |
| 304 |
if(l == plist) |
| 305 |
{ |
| 306 |
if(LIST_NEXT(LIST_NEXT(l)) == prev) |
| 307 |
{/* Check if have a triangle */ |
| 308 |
is_tri = TRUE; |
| 309 |
break; |
| 310 |
} |
| 311 |
|
| 312 |
if(is_convex) |
| 313 |
break; |
| 314 |
if(!cut) |
| 315 |
{ |
| 316 |
#ifdef DEBUG |
| 317 |
eputs("smTriangulate():Unable to triangulate\n"); |
| 318 |
#endif |
| 319 |
free_list(l); |
| 320 |
while(*add_ptr) |
| 321 |
{ |
| 322 |
t_id = pop_list(add_ptr); |
| 323 |
smDelete_tri(sm,t_id); |
| 324 |
} |
| 325 |
return(FALSE); |
| 326 |
} |
| 327 |
|
| 328 |
cut = FALSE; |
| 329 |
is_convex = TRUE; |
| 330 |
} |
| 331 |
prev = l; |
| 332 |
} |
| 333 |
if(is_tri) |
| 334 |
{ |
| 335 |
l = LIST_NEXT(l); |
| 336 |
enew = (int)LIST_DATA(l); |
| 337 |
t_id = smTriangulate_add_tri(sm,id0,id1,id2,e1,e2,&enew); |
| 338 |
*add_ptr = push_data(*add_ptr,t_id); |
| 339 |
free_list(l); |
| 340 |
} |
| 341 |
else |
| 342 |
if(!smTriangulateConvex(sm,l,add_ptr)) |
| 343 |
return(FALSE); |
| 344 |
|
| 345 |
/* Set triangle adjacencies based on edge adjacencies */ |
| 346 |
FOR_ALL_EDGES(enew) |
| 347 |
{ |
| 348 |
id0 = E_NTH_TRI(enew,0); |
| 349 |
id1 = E_NTH_TRI(enew,1); |
| 350 |
|
| 351 |
e1 = (T_WHICH_V(SM_NTH_TRI(sm,id0),E_NTH_VERT(enew,0))+2)%3; |
| 352 |
T_NTH_NBR(SM_NTH_TRI(sm,id0),e1) = id1; |
| 353 |
|
| 354 |
e2 = (T_WHICH_V(SM_NTH_TRI(sm,id1),E_NTH_VERT(enew,1))+2)%3; |
| 355 |
T_NTH_NBR(SM_NTH_TRI(sm,id1),e2) = id0; |
| 356 |
} |
| 357 |
return(TRUE); |
| 358 |
} |
| 359 |
|
| 360 |
eIn_tri(e,t) |
| 361 |
int e; |
| 362 |
TRI *t; |
| 363 |
{ |
| 364 |
|
| 365 |
if(T_NTH_V(t,0)==E_NTH_VERT(e,0)) |
| 366 |
return(T_NTH_V(t,1)==E_NTH_VERT(e,1)||T_NTH_V(t,2)==E_NTH_VERT(e,1)); |
| 367 |
else |
| 368 |
if(T_NTH_V(t,1)==E_NTH_VERT(e,0)) |
| 369 |
return(T_NTH_V(t,0)==E_NTH_VERT(e,1)||T_NTH_V(t,2)==E_NTH_VERT(e,1)); |
| 370 |
else if(T_NTH_V(t,2)==E_NTH_VERT(e,0)) |
| 371 |
return(T_NTH_V(t,0)==E_NTH_VERT(e,1)||T_NTH_V(t,1)==E_NTH_VERT(e,1)); |
| 372 |
|
| 373 |
return(FALSE); |
| 374 |
} |
| 375 |
|
| 376 |
/* Test the new set of triangles for Delaunay condition. 'Edges' contains |
| 377 |
all of the new edges added. The CCW triangle assoc with each edge is |
| 378 |
tested against the opposite vertex of the CW triangle. If the vertex |
| 379 |
lies inside the circle defined by the CCW triangle- the edge is swapped |
| 380 |
for the opposite diagonal |
| 381 |
*/ |
| 382 |
smFixEdges(sm,add_list) |
| 383 |
SM *sm; |
| 384 |
LIST *add_list; |
| 385 |
{ |
| 386 |
int e,t0_id,t1_id,e_new,e0,e1,e0_next,e1_next; |
| 387 |
int i,v0_id,v1_id,v2_id,p_id,t0_nid,t1_nid; |
| 388 |
FVECT v0,v1,v2,p,np,v; |
| 389 |
TRI *t0,*t1; |
| 390 |
|
| 391 |
FOR_ALL_EDGES(e) |
| 392 |
{ |
| 393 |
t0_id = E_NTH_TRI(e,0); |
| 394 |
t1_id = E_NTH_TRI(e,1); |
| 395 |
if((t0_id==INVALID) || (t1_id==INVALID)) |
| 396 |
{ |
| 397 |
#ifdef DEBUG |
| 398 |
error(CONSISTENCY,"smFix_edges: Unassigned edge nbr\n"); |
| 399 |
#endif |
| 400 |
} |
| 401 |
t0 = SM_NTH_TRI(sm,t0_id); |
| 402 |
t1 = SM_NTH_TRI(sm,t1_id); |
| 403 |
e0 = T_NTH_NBR_PTR(t1_id,t0); |
| 404 |
e1 = T_NTH_NBR_PTR(t0_id,t1); |
| 405 |
|
| 406 |
v0_id = E_NTH_VERT(e,0); |
| 407 |
v1_id = E_NTH_VERT(e,1); |
| 408 |
v2_id = T_NTH_V(t0,e0); |
| 409 |
p_id = T_NTH_V(t1,e1); |
| 410 |
|
| 411 |
smDir(sm,v0,v0_id); |
| 412 |
smDir(sm,v1,v1_id); |
| 413 |
smDir(sm,v2,v2_id); |
| 414 |
|
| 415 |
VCOPY(p,SM_NTH_WV(sm,p_id)); |
| 416 |
VSUB(p,p,SM_VIEW_CENTER(sm)); |
| 417 |
if(point_in_cone(p,v0,v1,v2)) |
| 418 |
{ |
| 419 |
smTris_swap_edge(sm,t0_id,t1_id,e0,e1,&t0_nid,&t1_nid,&add_list); |
| 420 |
|
| 421 |
/* Adjust the triangle pointers of the remaining edges to be |
| 422 |
processed |
| 423 |
*/ |
| 424 |
FOR_ALL_EDGES_FROM(e,i) |
| 425 |
{ |
| 426 |
if(E_NTH_TRI(i,0)==t0_id || E_NTH_TRI(i,0)==t1_id) |
| 427 |
{ |
| 428 |
if(eIn_tri(i,SM_NTH_TRI(sm,t0_nid))) |
| 429 |
SET_E_NTH_TRI(i,0,t0_nid); |
| 430 |
else |
| 431 |
SET_E_NTH_TRI(i,0,t1_nid); |
| 432 |
} |
| 433 |
|
| 434 |
if(E_NTH_TRI(i,1)==t0_id || E_NTH_TRI(i,1)==t1_id) |
| 435 |
{ |
| 436 |
if(eIn_tri(i,SM_NTH_TRI(sm,t0_nid))) |
| 437 |
SET_E_NTH_TRI(i,1,t0_nid); |
| 438 |
else |
| 439 |
SET_E_NTH_TRI(i,1,t1_nid); |
| 440 |
} |
| 441 |
} |
| 442 |
t0_id = t0_nid; |
| 443 |
t1_id = t1_nid; |
| 444 |
e_new = eNew_edge(); |
| 445 |
SET_E_NTH_VERT(e_new,0,p_id); |
| 446 |
SET_E_NTH_VERT(e_new,1,v2_id); |
| 447 |
SET_E_NTH_TRI(e_new,0,t0_id); |
| 448 |
SET_E_NTH_TRI(e_new,1,t1_id); |
| 449 |
} |
| 450 |
} |
| 451 |
/* Add/Delete the appropriate triangles from the stree */ |
| 452 |
smUpdate_locator(sm,add_list); |
| 453 |
} |
| 454 |
|
| 455 |
/* Remove vertex "id" from the mesh- and retriangulate the resulting |
| 456 |
hole: Returns TRUE if successful, FALSE otherwise. |
| 457 |
*/ |
| 458 |
int |
| 459 |
smRemoveVertex(sm,id) |
| 460 |
SM *sm; |
| 461 |
int id; |
| 462 |
{ |
| 463 |
LIST *b_list,*add_list,*del_list; |
| 464 |
int t_id,i; |
| 465 |
static int cnt=0; |
| 466 |
OBJECT *optr,*os; |
| 467 |
/* generate list of edges that form the boundary of the |
| 468 |
polygon formed by the triangles adjacent to vertex 'id' |
| 469 |
*/ |
| 470 |
del_list = NULL; |
| 471 |
b_list = smVertexStar(sm,id,&del_list); |
| 472 |
if(!b_list) |
| 473 |
{ |
| 474 |
if(del_list) |
| 475 |
free_list(del_list); |
| 476 |
return(FALSE); |
| 477 |
} |
| 478 |
add_list = NULL; |
| 479 |
/* Triangulate polygonal hole */ |
| 480 |
if(!smTriangulate(sm,id,b_list,&add_list)) |
| 481 |
{ |
| 482 |
free_list(del_list); |
| 483 |
return(FALSE); |
| 484 |
} |
| 485 |
else |
| 486 |
{ |
| 487 |
while(del_list) |
| 488 |
{ |
| 489 |
t_id = pop_list(&del_list); |
| 490 |
smDelete_tri(sm,t_id); |
| 491 |
} |
| 492 |
} |
| 493 |
/* Fix up new triangles to be Delaunay-delnode contains set of |
| 494 |
triangles to delete,add_list is the set of new triangles to add |
| 495 |
*/ |
| 496 |
smFixEdges(sm,add_list); |
| 497 |
|
| 498 |
return(TRUE); |
| 499 |
} |
| 500 |
|
| 501 |
|
| 502 |
|
| 503 |
|
| 504 |
|
| 505 |
|
| 506 |
|
| 507 |
|
| 508 |
|
| 509 |
|
| 510 |
|
| 511 |
|
| 512 |
|
| 513 |
|
| 514 |
|
