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/*
** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
** Copyright (C) [dates of first publication] Silicon Graphics, Inc.
** All Rights Reserved.
**
** Permission is hereby granted, free of charge, to any person obtaining a copy
** of this software and associated documentation files (the "Software"), to deal
** in the Software without restriction, including without limitation the rights
** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
** of the Software, and to permit persons to whom the Software is furnished to do so,
** subject to the following conditions:
**
** The above copyright notice including the dates of first publication and either this
** permission notice or a reference to http://oss.sgi.com/projects/FreeB/ shall be
** included in all copies or substantial portions of the Software.
**
** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
** INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
** PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL SILICON GRAPHICS, INC.
** BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
** OR OTHER DEALINGS IN THE SOFTWARE.
**
** Except as contained in this notice, the name of Silicon Graphics, Inc. shall not
** be used in advertising or otherwise to promote the sale, use or other dealings in
** this Software without prior written authorization from Silicon Graphics, Inc.
*/
/*
** Author: Eric Veach, July 1994.
*/
//#include "tesos.h"
#include <stddef.h>
#include <assert.h>
#include "mesh.h"
#include "geom.h"
#include "bucketalloc.h"
#define TRUE 1
#define FALSE 0
/************************ Utility Routines ************************/
/* Allocate and free half-edges in pairs for efficiency.
* The *only* place that should use this fact is allocation/free.
*/
typedef struct { TESShalfEdge e, eSym; } EdgePair;
/* MakeEdge creates a new pair of half-edges which form their own loop.
* No vertex or face structures are allocated, but these must be assigned
* before the current edge operation is completed.
*/
static TESShalfEdge *MakeEdge( TESSmesh* mesh, TESShalfEdge *eNext )
{
TESShalfEdge *e;
TESShalfEdge *eSym;
TESShalfEdge *ePrev;
EdgePair *pair = (EdgePair *)bucketAlloc( mesh->edgeBucket );
if (pair == NULL) return NULL;
e = &pair->e;
eSym = &pair->eSym;
/* Make sure eNext points to the first edge of the edge pair */
if( eNext->Sym < eNext ) { eNext = eNext->Sym; }
/* Insert in circular doubly-linked list before eNext.
* Note that the prev pointer is stored in Sym->next.
*/
ePrev = eNext->Sym->next;
eSym->next = ePrev;
ePrev->Sym->next = e;
e->next = eNext;
eNext->Sym->next = eSym;
e->Sym = eSym;
e->Onext = e;
e->Lnext = eSym;
e->Org = NULL;
e->Lface = NULL;
e->winding = 0;
e->activeRegion = NULL;
e->mark = 0;
eSym->Sym = e;
eSym->Onext = eSym;
eSym->Lnext = e;
eSym->Org = NULL;
eSym->Lface = NULL;
eSym->winding = 0;
eSym->activeRegion = NULL;
eSym->mark = 0;
return e;
}
/* Splice( a, b ) is best described by the Guibas/Stolfi paper or the
* CS348a notes (see mesh.h). Basically it modifies the mesh so that
* a->Onext and b->Onext are exchanged. This can have various effects
* depending on whether a and b belong to different face or vertex rings.
* For more explanation see tessMeshSplice() below.
*/
static void Splice( TESShalfEdge *a, TESShalfEdge *b )
{
TESShalfEdge *aOnext = a->Onext;
TESShalfEdge *bOnext = b->Onext;
aOnext->Sym->Lnext = b;
bOnext->Sym->Lnext = a;
a->Onext = bOnext;
b->Onext = aOnext;
}
/* MakeVertex( newVertex, eOrig, vNext ) attaches a new vertex and makes it the
* origin of all edges in the vertex loop to which eOrig belongs. "vNext" gives
* a place to insert the new vertex in the global vertex list. We insert
* the new vertex *before* vNext so that algorithms which walk the vertex
* list will not see the newly created vertices.
*/
static void MakeVertex( TESSvertex *newVertex,
TESShalfEdge *eOrig, TESSvertex *vNext )
{
TESShalfEdge *e;
TESSvertex *vPrev;
TESSvertex *vNew = newVertex;
assert(vNew != NULL);
/* insert in circular doubly-linked list before vNext */
vPrev = vNext->prev;
vNew->prev = vPrev;
vPrev->next = vNew;
vNew->next = vNext;
vNext->prev = vNew;
vNew->anEdge = eOrig;
/* leave coords, s, t undefined */
/* fix other edges on this vertex loop */
e = eOrig;
do {
e->Org = vNew;
e = e->Onext;
} while( e != eOrig );
}
/* MakeFace( newFace, eOrig, fNext ) attaches a new face and makes it the left
* face of all edges in the face loop to which eOrig belongs. "fNext" gives
* a place to insert the new face in the global face list. We insert
* the new face *before* fNext so that algorithms which walk the face
* list will not see the newly created faces.
*/
static void MakeFace( TESSface *newFace, TESShalfEdge *eOrig, TESSface *fNext )
{
TESShalfEdge *e;
TESSface *fPrev;
TESSface *fNew = newFace;
assert(fNew != NULL);
/* insert in circular doubly-linked list before fNext */
fPrev = fNext->prev;
fNew->prev = fPrev;
fPrev->next = fNew;
fNew->next = fNext;
fNext->prev = fNew;
fNew->anEdge = eOrig;
fNew->trail = NULL;
fNew->marked = FALSE;
/* The new face is marked "inside" if the old one was. This is a
* convenience for the common case where a face has been split in two.
*/
fNew->inside = fNext->inside;
/* fix other edges on this face loop */
e = eOrig;
do {
e->Lface = fNew;
e = e->Lnext;
} while( e != eOrig );
}
/* 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 );
}
/* 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 );
}
/* 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 );
}
/****************** Basic Edge Operations **********************/
/* 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;
}
/* tessMeshSplice( eOrg, eDst ) is the basic operation for changing the
* mesh connectivity and topology. It changes the mesh so that
* eOrg->Onext <- OLD( eDst->Onext )
* eDst->Onext <- OLD( eOrg->Onext )
* where OLD(...) means the value before the meshSplice operation.
*
* This can have two effects on the vertex structure:
* - if eOrg->Org != eDst->Org, the two vertices are merged together
* - if eOrg->Org == eDst->Org, the origin is split into two vertices
* In both cases, eDst->Org is changed and eOrg->Org is untouched.
*
* Similarly (and independently) for the face structure,
* - if eOrg->Lface == eDst->Lface, one loop is split into two
* - if eOrg->Lface != eDst->Lface, two distinct loops are joined into one
* In both cases, eDst->Lface is changed and eOrg->Lface is unaffected.
*
* Some special cases:
* If eDst == eOrg, the operation has no effect.
* If eDst == eOrg->Lnext, the new face will have a single edge.
* If eDst == eOrg->Lprev, the old face will have a single edge.
* If eDst == eOrg->Onext, the new vertex will have a single edge.
* If eDst == eOrg->Oprev, the old vertex will have a single edge.
*/
int tessMeshSplice( TESSmesh* mesh, TESShalfEdge *eOrg, TESShalfEdge *eDst )
{
int joiningLoops = FALSE;
int joiningVertices = FALSE;
if( eOrg == eDst ) return 1;
if( eDst->Org != eOrg->Org ) {
/* We are merging two disjoint vertices -- destroy eDst->Org */
joiningVertices = TRUE;
KillVertex( mesh, eDst->Org, eOrg->Org );
}
if( eDst->Lface != eOrg->Lface ) {
/* We are connecting two disjoint loops -- destroy eDst->Lface */
joiningLoops = TRUE;
KillFace( mesh, eDst->Lface, eOrg->Lface );
}
/* Change the edge structure */
Splice( eDst, eOrg );
if( ! joiningVertices ) {
TESSvertex *newVertex = (TESSvertex*)bucketAlloc( mesh->vertexBucket );
if (newVertex == NULL) return 0;
/* We split one vertex into two -- the new vertex is eDst->Org.
* Make sure the old vertex points to a valid half-edge.
*/
MakeVertex( newVertex, eDst, eOrg->Org );
eOrg->Org->anEdge = eOrg;
}
if( ! joiningLoops ) {
TESSface *newFace = (TESSface*)bucketAlloc( mesh->faceBucket );
if (newFace == NULL) return 0;
/* We split one loop into two -- the new loop is eDst->Lface.
* Make sure the old face points to a valid half-edge.
*/
MakeFace( newFace, eDst, eOrg->Lface );
eOrg->Lface->anEdge = eOrg;
}
return 1;
}
/* tessMeshDelete( eDel ) removes the edge eDel. There are several cases:
* if (eDel->Lface != eDel->Rface), we join two loops into one; the loop
* eDel->Lface is deleted. Otherwise, we are splitting one loop into two;
* the newly created loop will contain eDel->Dst. If the deletion of eDel
* would create isolated vertices, those are deleted as well.
*
* This function could be implemented as two calls to tessMeshSplice
* plus a few calls to memFree, but this would allocate and delete
* unnecessary vertices and faces.
*/
int tessMeshDelete( TESSmesh *mesh, TESShalfEdge *eDel )
{
TESShalfEdge *eDelSym = eDel->Sym;
int joiningLoops = FALSE;
/* First step: disconnect the origin vertex eDel->Org. We make all
* changes to get a consistent mesh in this "intermediate" state.
*/
if( eDel->Lface != eDel->Rface ) {
/* We are joining two loops into one -- remove the left face */
joiningLoops = TRUE;
KillFace( mesh, eDel->Lface, eDel->Rface );
}
if( eDel->Onext == eDel ) {
KillVertex( mesh, eDel->Org, NULL );
} else {
/* Make sure that eDel->Org and eDel->Rface point to valid half-edges */
eDel->Rface->anEdge = eDel->Oprev;
eDel->Org->anEdge = eDel->Onext;
Splice( eDel, eDel->Oprev );
if( ! joiningLoops ) {
TESSface *newFace= (TESSface*)bucketAlloc( mesh->faceBucket );
if (newFace == NULL) return 0;
/* We are splitting one loop into two -- create a new loop for eDel. */
MakeFace( newFace, eDel, eDel->Lface );
}
}
/* Claim: the mesh is now in a consistent state, except that eDel->Org
* may have been deleted. Now we disconnect eDel->Dst.
*/
if( eDelSym->Onext == eDelSym ) {
KillVertex( mesh, eDelSym->Org, NULL );
KillFace( mesh, eDelSym->Lface, NULL );
} else {
/* Make sure that eDel->Dst and eDel->Lface point to valid half-edges */
eDel->Lface->anEdge = eDelSym->Oprev;
eDelSym->Org->anEdge = eDelSym->Onext;
Splice( eDelSym, eDelSym->Oprev );
}
/* Any isolated vertices or faces have already been freed. */
KillEdge( mesh, eDel );
return 1;
}
/******************** Other Edge Operations **********************/
/* All these routines can be implemented with the basic edge
* operations above. They are provided for convenience and efficiency.
*/
/* tessMeshAddEdgeVertex( eOrg ) creates a new edge eNew such that
* eNew == eOrg->Lnext, and eNew->Dst is a newly created vertex.
* eOrg and eNew will have the same left face.
*/
TESShalfEdge *tessMeshAddEdgeVertex( TESSmesh *mesh, TESShalfEdge *eOrg )
{
TESShalfEdge *eNewSym;
TESShalfEdge *eNew = MakeEdge( mesh, eOrg );
if (eNew == NULL) return NULL;
eNewSym = eNew->Sym;
/* Connect the new edge appropriately */
Splice( eNew, eOrg->Lnext );
/* Set the vertex and face information */
eNew->Org = eOrg->Dst;
{
TESSvertex *newVertex= (TESSvertex*)bucketAlloc( mesh->vertexBucket );
if (newVertex == NULL) return NULL;
MakeVertex( newVertex, eNewSym, eNew->Org );
}
eNew->Lface = eNewSym->Lface = eOrg->Lface;
return eNew;
}
/* tessMeshSplitEdge( eOrg ) splits eOrg into two edges eOrg and eNew,
* such that eNew == eOrg->Lnext. The new vertex is eOrg->Dst == eNew->Org.
* eOrg and eNew will have the same left face.
*/
TESShalfEdge *tessMeshSplitEdge( TESSmesh *mesh, TESShalfEdge *eOrg )
{
TESShalfEdge *eNew;
TESShalfEdge *tempHalfEdge= tessMeshAddEdgeVertex( mesh, eOrg );
if (tempHalfEdge == NULL) return NULL;
eNew = tempHalfEdge->Sym;
/* Disconnect eOrg from eOrg->Dst and connect it to eNew->Org */
Splice( eOrg->Sym, eOrg->Sym->Oprev );
Splice( eOrg->Sym, eNew );
/* Set the vertex and face information */
eOrg->Dst = eNew->Org;
eNew->Dst->anEdge = eNew->Sym; /* may have pointed to eOrg->Sym */
eNew->Rface = eOrg->Rface;
eNew->winding = eOrg->winding; /* copy old winding information */
eNew->Sym->winding = eOrg->Sym->winding;
return eNew;
}
/* tessMeshConnect( eOrg, eDst ) creates a new edge from eOrg->Dst
* to eDst->Org, and returns the corresponding half-edge eNew.
* If eOrg->Lface == eDst->Lface, this splits one loop into two,
* and the newly created loop is eNew->Lface. Otherwise, two disjoint
* loops are merged into one, and the loop eDst->Lface is destroyed.
*
* If (eOrg == eDst), the new face will have only two edges.
* If (eOrg->Lnext == eDst), the old face is reduced to a single edge.
* If (eOrg->Lnext->Lnext == eDst), the old face is reduced to two edges.
*/
TESShalfEdge *tessMeshConnect( TESSmesh *mesh, TESShalfEdge *eOrg, TESShalfEdge *eDst )
{
TESShalfEdge *eNewSym;
int joiningLoops = FALSE;
TESShalfEdge *eNew = MakeEdge( mesh, eOrg );
if (eNew == NULL) return NULL;
eNewSym = eNew->Sym;
if( eDst->Lface != eOrg->Lface ) {
/* We are connecting two disjoint loops -- destroy eDst->Lface */
joiningLoops = TRUE;
KillFace( mesh, eDst->Lface, eOrg->Lface );
}
/* Connect the new edge appropriately */
Splice( eNew, eOrg->Lnext );
Splice( eNewSym, eDst );
/* Set the vertex and face information */
eNew->Org = eOrg->Dst;
eNewSym->Org = eDst->Org;
eNew->Lface = eNewSym->Lface = eOrg->Lface;
/* Make sure the old face points to a valid half-edge */
eOrg->Lface->anEdge = eNewSym;
if( ! joiningLoops ) {
TESSface *newFace= (TESSface*)bucketAlloc( mesh->faceBucket );
if (newFace == NULL) return NULL;
/* We split one loop into two -- the new loop is eNew->Lface */
MakeFace( newFace, eNew, eOrg->Lface );
}
return eNew;
}
/******************** Other Operations **********************/
/* 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 );
}
/* tessMeshNewMesh() creates a new mesh with no edges, no vertices,
* and no loops (what we usually call a "face").
*/
TESSmesh *tessMeshNewMesh( TESSalloc* alloc )
{
TESSvertex *v;
TESSface *f;
TESShalfEdge *e;
TESShalfEdge *eSym;
TESSmesh *mesh = (TESSmesh *)alloc->memalloc( alloc->userData, sizeof( TESSmesh ));
if (mesh == NULL) {
return NULL;
}
if (alloc->meshEdgeBucketSize < 16)
alloc->meshEdgeBucketSize = 16;
if (alloc->meshEdgeBucketSize > 4096)
alloc->meshEdgeBucketSize = 4096;
if (alloc->meshVertexBucketSize < 16)
alloc->meshVertexBucketSize = 16;
if (alloc->meshVertexBucketSize > 4096)
alloc->meshVertexBucketSize = 4096;
if (alloc->meshFaceBucketSize < 16)
alloc->meshFaceBucketSize = 16;
if (alloc->meshFaceBucketSize > 4096)
alloc->meshFaceBucketSize = 4096;
mesh->edgeBucket = createBucketAlloc( alloc, "Mesh Edges", sizeof(EdgePair), alloc->meshEdgeBucketSize );
mesh->vertexBucket = createBucketAlloc( alloc, "Mesh Vertices", sizeof(TESSvertex), alloc->meshVertexBucketSize );
mesh->faceBucket = createBucketAlloc( alloc, "Mesh Faces", sizeof(TESSface), alloc->meshFaceBucketSize );
v = &mesh->vHead;
f = &mesh->fHead;
e = &mesh->eHead;
eSym = &mesh->eHeadSym;
v->next = v->prev = v;
v->anEdge = NULL;
f->next = f->prev = f;
f->anEdge = NULL;
f->trail = NULL;
f->marked = FALSE;
f->inside = FALSE;
e->next = e;
e->Sym = eSym;
e->Onext = NULL;
e->Lnext = NULL;
e->Org = NULL;
e->Lface = NULL;
e->winding = 0;
e->activeRegion = NULL;
eSym->next = eSym;
eSym->Sym = e;
eSym->Onext = NULL;
eSym->Lnext = NULL;
eSym->Org = NULL;
eSym->Lface = NULL;
eSym->winding = 0;
eSym->activeRegion = NULL;
return mesh;
}
/* tessMeshUnion( mesh1, mesh2 ) forms the union of all structures in
* both meshes, and returns the new mesh (the old meshes are destroyed).
*/
TESSmesh *tessMeshUnion( TESSalloc* alloc, TESSmesh *mesh1, TESSmesh *mesh2 )
{
TESSface *f1 = &mesh1->fHead;
TESSvertex *v1 = &mesh1->vHead;
TESShalfEdge *e1 = &mesh1->eHead;
TESSface *f2 = &mesh2->fHead;
TESSvertex *v2 = &mesh2->vHead;
TESShalfEdge *e2 = &mesh2->eHead;
/* Add the faces, vertices, and edges of mesh2 to those of mesh1 */
if( f2->next != f2 ) {
f1->prev->next = f2->next;
f2->next->prev = f1->prev;
f2->prev->next = f1;
f1->prev = f2->prev;
}
if( v2->next != v2 ) {
v1->prev->next = v2->next;
v2->next->prev = v1->prev;
v2->prev->next = v1;
v1->prev = v2->prev;
}
if( e2->next != e2 ) {
e1->Sym->next->Sym->next = e2->next;
e2->next->Sym->next = e1->Sym->next;
e2->Sym->next->Sym->next = e1;
e1->Sym->next = e2->Sym->next;
}
alloc->memfree( alloc->userData, mesh2 );
return mesh1;
}
static int CountFaceVerts( TESSface *f )
{
TESShalfEdge *eCur = f->anEdge;
int n = 0;
do
{
n++;
eCur = eCur->Lnext;
}
while (eCur != f->anEdge);
return n;
}
int tessMeshMergeConvexFaces( TESSmesh *mesh, int maxVertsPerFace )
{
TESSface *f;
TESShalfEdge *eCur, *eNext, *eSym;
TESSvertex *vStart;
int curNv, symNv;
for( f = mesh->fHead.next; f != &mesh->fHead; f = f->next )
{
// Skip faces which are outside the result.
if( !f->inside )
continue;
eCur = f->anEdge;
vStart = eCur->Org;
while (1)
{
eNext = eCur->Lnext;
eSym = eCur->Sym;
// Try to merge if the neighbour face is valid.
if( eSym && eSym->Lface && eSym->Lface->inside )
{
// Try to merge the neighbour faces if the resulting polygons
// does not exceed maximum number of vertices.
curNv = CountFaceVerts( f );
symNv = CountFaceVerts( eSym->Lface );
if( (curNv+symNv-2) <= maxVertsPerFace )
{
// Merge if the resulting poly is convex.
if( VertCCW( eCur->Lprev->Org, eCur->Org, eSym->Lnext->Lnext->Org ) &&
VertCCW( eSym->Lprev->Org, eSym->Org, eCur->Lnext->Lnext->Org ) )
{
eNext = eSym->Lnext;
if( !tessMeshDelete( mesh, eSym ) )
return 0;
eCur = 0;
}
}
}
if( eCur && eCur->Lnext->Org == vStart )
break;
// Continue to next edge.
eCur = eNext;
}
}
return 1;
}
void tessMeshFlipEdge( TESSmesh *mesh, TESShalfEdge *edge )
{
TESShalfEdge *a0 = edge;
TESShalfEdge *a1 = a0->Lnext;
TESShalfEdge *a2 = a1->Lnext;
TESShalfEdge *b0 = edge->Sym;
TESShalfEdge *b1 = b0->Lnext;
TESShalfEdge *b2 = b1->Lnext;
TESSvertex *aOrg = a0->Org;
TESSvertex *aOpp = a2->Org;
TESSvertex *bOrg = b0->Org;
TESSvertex *bOpp = b2->Org;
TESSface *fa = a0->Lface;
TESSface *fb = b0->Lface;
assert(EdgeIsInternal(edge));
assert(a2->Lnext == a0);
assert(b2->Lnext == b0);
a0->Org = bOpp;
a0->Onext = b1->Sym;
b0->Org = aOpp;
b0->Onext = a1->Sym;
a2->Onext = b0;
b2->Onext = a0;
b1->Onext = a2->Sym;
a1->Onext = b2->Sym;
a0->Lnext = a2;
a2->Lnext = b1;
b1->Lnext = a0;
b0->Lnext = b2;
b2->Lnext = a1;
a1->Lnext = b0;
a1->Lface = fb;
b1->Lface = fa;
fa->anEdge = a0;
fb->anEdge = b0;
if (aOrg->anEdge == a0) aOrg->anEdge = b1;
if (bOrg->anEdge == b0) bOrg->anEdge = a1;
assert( a0->Lnext->Onext->Sym == a0 );
assert( a0->Onext->Sym->Lnext == a0 );
assert( a0->Org->anEdge->Org == a0->Org );
assert( a1->Lnext->Onext->Sym == a1 );
assert( a1->Onext->Sym->Lnext == a1 );
assert( a1->Org->anEdge->Org == a1->Org );
assert( a2->Lnext->Onext->Sym == a2 );
assert( a2->Onext->Sym->Lnext == a2 );
assert( a2->Org->anEdge->Org == a2->Org );
assert( b0->Lnext->Onext->Sym == b0 );
assert( b0->Onext->Sym->Lnext == b0 );
assert( b0->Org->anEdge->Org == b0->Org );
assert( b1->Lnext->Onext->Sym == b1 );
assert( b1->Onext->Sym->Lnext == b1 );
assert( b1->Org->anEdge->Org == b1->Org );
assert( b2->Lnext->Onext->Sym == b2 );
assert( b2->Onext->Sym->Lnext == b2 );
assert( b2->Org->anEdge->Org == b2->Org );
assert(aOrg->anEdge->Org == aOrg);
assert(bOrg->anEdge->Org == bOrg);
assert(a0->Oprev->Onext->Org == a0->Org);
}
#ifdef DELETE_BY_ZAPPING
/* tessMeshDeleteMesh( mesh ) will free all storage for any valid mesh.
*/
void tessMeshDeleteMesh( TESSalloc* alloc, TESSmesh *mesh )
{
TESSface *fHead = &mesh->fHead;
while( fHead->next != fHead ) {
tessMeshZapFace( fHead->next );
}
assert( mesh->vHead.next == &mesh->vHead );
alloc->memfree( alloc->userData, mesh );
}
#else
/* tessMeshDeleteMesh( mesh ) will free all storage for any valid mesh.
*/
void tessMeshDeleteMesh( TESSalloc* alloc, TESSmesh *mesh )
{
deleteBucketAlloc(mesh->edgeBucket);
deleteBucketAlloc(mesh->vertexBucket);
deleteBucketAlloc(mesh->faceBucket);
alloc->memfree( alloc->userData, mesh );
}
#endif
#ifndef NDEBUG
/* tessMeshCheckMesh( mesh ) checks a mesh for self-consistency.
*/
void tessMeshCheckMesh( TESSmesh *mesh )
{
TESSface *fHead = &mesh->fHead;
TESSvertex *vHead = &mesh->vHead;
TESShalfEdge *eHead = &mesh->eHead;
TESSface *f, *fPrev;
TESSvertex *v, *vPrev;
TESShalfEdge *e, *ePrev;
fPrev = fHead;
for( fPrev = fHead ; (f = fPrev->next) != fHead; fPrev = f) {
assert( f->prev == fPrev );
e = f->anEdge;
do {
assert( e->Sym != e );
assert( e->Sym->Sym == e );
assert( e->Lnext->Onext->Sym == e );
assert( e->Onext->Sym->Lnext == e );
assert( e->Lface == f );
e = e->Lnext;
} while( e != f->anEdge );
}
assert( f->prev == fPrev && f->anEdge == NULL );
vPrev = vHead;
for( vPrev = vHead ; (v = vPrev->next) != vHead; vPrev = v) {
assert( v->prev == vPrev );
e = v->anEdge;
do {
assert( e->Sym != e );
assert( e->Sym->Sym == e );
assert( e->Lnext->Onext->Sym == e );
assert( e->Onext->Sym->Lnext == e );
assert( e->Org == v );
e = e->Onext;
} while( e != v->anEdge );
}
assert( v->prev == vPrev && v->anEdge == NULL );
ePrev = eHead;
for( ePrev = eHead ; (e = ePrev->next) != eHead; ePrev = e) {
assert( e->Sym->next == ePrev->Sym );
assert( e->Sym != e );
assert( e->Sym->Sym == e );
assert( e->Org != NULL );
assert( e->Dst != NULL );
assert( e->Lnext->Onext->Sym == e );
assert( e->Onext->Sym->Lnext == e );
}
assert( e->Sym->next == ePrev->Sym
&& e->Sym == &mesh->eHeadSym
&& e->Sym->Sym == e
&& e->Org == NULL && e->Dst == NULL
&& e->Lface == NULL && e->Rface == NULL );
}
#endif