TESShalfEdge *stackPop( EdgeStack *stack )
{
TESShalfEdge *e = NULL;
EdgeStackNode *node = stack->top;
if (node) {
stack->top = node->next;
e = node->edge;
bucketFree( stack->nodeBucket, node );
}
return e;
}
static void DeleteRegion( TESStesselator *tess, ActiveRegion *reg )
{
if( reg->fixUpperEdge ) {
/* It was created with zero winding number, so it better be
* deleted with zero winding number (ie. it better not get merged
* with a real edge).
*/
assert( reg->eUp->winding == 0 );
}
reg->eUp->activeRegion = NULL;
dictDelete( tess->dict, reg->nodeUp );
bucketFree( tess->regionPool, reg );
}
/* tessMeshMakeEdge creates one edge, two vertices, and a loop (face).
* The loop consists of the two new half-edges.
*/
TESShalfEdge *tessMeshMakeEdge( TESSmesh *mesh )
{
TESSvertex *newVertex1 = (TESSvertex*)bucketAlloc(mesh->vertexBucket);
TESSvertex *newVertex2 = (TESSvertex*)bucketAlloc(mesh->vertexBucket);
TESSface *newFace = (TESSface*)bucketAlloc(mesh->faceBucket);
TESShalfEdge *e;
/* if any one is null then all get freed */
if (newVertex1 == NULL || newVertex2 == NULL || newFace == NULL) {
if (newVertex1 != NULL) bucketFree( mesh->vertexBucket, newVertex1 );
if (newVertex2 != NULL) bucketFree( mesh->vertexBucket, newVertex2 );
if (newFace != NULL) bucketFree( mesh->faceBucket, newFace );
return NULL;
}
e = MakeEdge( mesh, &mesh->eHead );
if (e == NULL) return NULL;
MakeVertex( newVertex1, e, &mesh->vHead );
MakeVertex( newVertex2, e->Sym, &mesh->vHead );
MakeFace( newFace, e, &mesh->fHead );
return e;
}
/* KillEdge( eDel ) destroys an edge (the half-edges eDel and eDel->Sym),
* and removes from the global edge list.
*/
static void KillEdge( TESSmesh *mesh, TESShalfEdge *eDel )
{
TESShalfEdge *ePrev, *eNext;
/* Half-edges are allocated in pairs, see EdgePair above */
if( eDel->Sym < eDel ) { eDel = eDel->Sym; }
/* delete from circular doubly-linked list */
eNext = eDel->next;
ePrev = eDel->Sym->next;
eNext->Sym->next = ePrev;
ePrev->Sym->next = eNext;
bucketFree( mesh->edgeBucket, eDel );
}
/* tessMeshZapFace( fZap ) destroys a face and removes it from the
* global face list. All edges of fZap will have a NULL pointer as their
* left face. Any edges which also have a NULL pointer as their right face
* are deleted entirely (along with any isolated vertices this produces).
* An entire mesh can be deleted by zapping its faces, one at a time,
* in any order. Zapped faces cannot be used in further mesh operations!
*/
void tessMeshZapFace( TESSmesh *mesh, TESSface *fZap )
{
TESShalfEdge *eStart = fZap->anEdge;
TESShalfEdge *e, *eNext, *eSym;
TESSface *fPrev, *fNext;
/* walk around face, deleting edges whose right face is also NULL */
eNext = eStart->Lnext;
do {
e = eNext;
eNext = e->Lnext;
e->Lface = NULL;
if( e->Rface == NULL ) {
/* delete the edge -- see TESSmeshDelete above */
if( e->Onext == e ) {
KillVertex( mesh, e->Org, NULL );
} else {
/* Make sure that e->Org points to a valid half-edge */
e->Org->anEdge = e->Onext;
Splice( e, e->Oprev );
}
eSym = e->Sym;
if( eSym->Onext == eSym ) {
KillVertex( mesh, eSym->Org, NULL );
} else {
/* Make sure that eSym->Org points to a valid half-edge */
eSym->Org->anEdge = eSym->Onext;
Splice( eSym, eSym->Oprev );
}
KillEdge( mesh, e );
}
} while( e != eStart );
/* delete from circular doubly-linked list */
fPrev = fZap->prev;
fNext = fZap->next;
fNext->prev = fPrev;
fPrev->next = fNext;
bucketFree( mesh->faceBucket, fZap );
}
/* KillFace( fDel ) destroys a face and removes it from the global face
* list. It updates the face loop to point to a given new face.
*/
static void KillFace( TESSmesh *mesh, TESSface *fDel, TESSface *newLface )
{
TESShalfEdge *e, *eStart = fDel->anEdge;
TESSface *fPrev, *fNext;
/* change the left face of all affected edges */
e = eStart;
do {
e->Lface = newLface;
e = e->Lnext;
} while( e != eStart );
/* delete from circular doubly-linked list */
fPrev = fDel->prev;
fNext = fDel->next;
fNext->prev = fPrev;
fPrev->next = fNext;
bucketFree( mesh->faceBucket, fDel );
}
/* KillVertex( vDel ) destroys a vertex and removes it from the global
* vertex list. It updates the vertex loop to point to a given new vertex.
*/
static void KillVertex( TESSmesh *mesh, TESSvertex *vDel, TESSvertex *newOrg )
{
TESShalfEdge *e, *eStart = vDel->anEdge;
TESSvertex *vPrev, *vNext;
/* change the origin of all affected edges */
e = eStart;
do {
e->Org = newOrg;
e = e->Onext;
} while( e != eStart );
/* delete from circular doubly-linked list */
vPrev = vDel->prev;
vNext = vDel->next;
vNext->prev = vPrev;
vPrev->next = vNext;
bucketFree( mesh->vertexBucket, vDel );
}
/* really tessDictListDelete */
void dictDelete( Dict *dict, DictNode *node ) /*ARGSUSED*/
{
node->next->prev = node->prev;
node->prev->next = node->next;
bucketFree( dict->nodePool, node );
}
