/* Store in the rightface field of each edge the number of the face on
the right hand side of that edge. Faces are numbered 0,1,.... Also
store in facestart[i] an example of an edge in the clockwise orientation
of the face boundary, and the size of the face in facesize[i], for each i.
Returns the number of faces. */
void makeDual() {
register int i, sz;
register EDGE *e, *ex, *ef, *efx;
RESETMARKS;
nf = 0;
for (i = 0; i < nv; ++i) {
e = ex = firstedge[i];
do {
if (!ISMARKEDLO(e)) {
facestart[nf] = ef = efx = e;
faceSets[nf] = EMPTY_SET;
sz = 0;
do {
ef->rightface = nf;
ADD(faceSets[nf], ef->end);
MARKLO(ef);
ef = ef->inverse->prev;
++sz;
} while (ef != efx);
faceSize[nf] = sz;
++nf;
}
e = e->next;
} while (e != ex);
}
}
/* Store in the rightface field of each edge the number of the face on
the right hand side of that edge. Faces are numbered 0,1,.... Also
store in facestart[i] an example of an edge in the clockwise orientation
of the face boundary, and the size of the face in facesize[i], for each i.
Returns the number of faces. */
void makeDual(PLANE_GRAPH *pg) {
register int i, sz;
register PG_EDGE *e, *ex, *ef, *efx;
RESETMARKS(pg);
//first allocate the memory to store faces if this has not yet been done
int maxf = 2*pg->maxn - 4;
if(pg->maxf < maxf){
if(pg->facestart!=NULL){
free(pg->facestart);
}
if(pg->faceSize!=NULL){
free(pg->faceSize);
}
pg->maxf = maxf;
pg->facestart = (PG_EDGE **)malloc(sizeof(PG_EDGE *)*maxf);
if(pg->facestart == NULL){
pg->maxf = 0;
return;
}
pg->faceSize = (int *)malloc(sizeof(int)*maxf);
if(pg->faceSize == NULL){
pg->maxf = 0;
free(pg->facestart);
return;
}
}
int nf = 0;
for (i = 0; i < pg->nv; ++i) {
e = ex = pg->firstedge[i];
do {
if (!ISMARKEDLO(e)) {
pg->facestart[nf] = ef = efx = e;
sz = 0;
do {
ef->rightface = nf;
MARKLO(ef);
ef = ef->inverse->prev;
++sz;
} while (ef != efx);
pg->faceSize[nf] = sz;
++nf;
}
e = e->next;
} while (e != ex);
}
pg->nf = nf;
pg->dualComputed = TRUE;
}
