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diff --git a/mesalib/src/glu/sgi/libtess/mesh.c b/mesalib/src/glu/sgi/libtess/mesh.c
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+/*
+ * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
+ * Copyright (C) 1991-2000 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 "gluos.h"
+#include <stddef.h>
+#include <assert.h>
+#include "mesh.h"
+#include "memalloc.h"
+
+#define TRUE 1
+#define FALSE 0
+
+static GLUvertex *allocVertex()
+{
+ return (GLUvertex *)memAlloc( sizeof( GLUvertex ));
+}
+
+static GLUface *allocFace()
+{
+ return (GLUface *)memAlloc( sizeof( GLUface ));
+}
+
+/************************ Utility Routines ************************/
+
+/* Allocate and free half-edges in pairs for efficiency.
+ * The *only* place that should use this fact is allocation/free.
+ */
+typedef struct { GLUhalfEdge 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 GLUhalfEdge *MakeEdge( GLUhalfEdge *eNext )
+{
+ GLUhalfEdge *e;
+ GLUhalfEdge *eSym;
+ GLUhalfEdge *ePrev;
+ EdgePair *pair = (EdgePair *)memAlloc( sizeof( EdgePair ));
+ 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;
+
+ eSym->Sym = e;
+ eSym->Onext = eSym;
+ eSym->Lnext = e;
+ eSym->Org = NULL;
+ eSym->Lface = NULL;
+ eSym->winding = 0;
+ eSym->activeRegion = NULL;
+
+ 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 __gl_meshSplice() below.
+ */
+static void Splice( GLUhalfEdge *a, GLUhalfEdge *b )
+{
+ GLUhalfEdge *aOnext = a->Onext;
+ GLUhalfEdge *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( GLUvertex *newVertex,
+ GLUhalfEdge *eOrig, GLUvertex *vNext )
+{
+ GLUhalfEdge *e;
+ GLUvertex *vPrev;
+ GLUvertex *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;
+ vNew->data = NULL;
+ /* 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( GLUface *newFace, GLUhalfEdge *eOrig, GLUface *fNext )
+{
+ GLUhalfEdge *e;
+ GLUface *fPrev;
+ GLUface *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->data = NULL;
+ 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( GLUhalfEdge *eDel )
+{
+ GLUhalfEdge *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;
+
+ memFree( 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( GLUvertex *vDel, GLUvertex *newOrg )
+{
+ GLUhalfEdge *e, *eStart = vDel->anEdge;
+ GLUvertex *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;
+
+ memFree( 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( GLUface *fDel, GLUface *newLface )
+{
+ GLUhalfEdge *e, *eStart = fDel->anEdge;
+ GLUface *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;
+
+ memFree( fDel );
+}
+
+
+/****************** Basic Edge Operations **********************/
+
+/* __gl_meshMakeEdge creates one edge, two vertices, and a loop (face).
+ * The loop consists of the two new half-edges.
+ */
+GLUhalfEdge *__gl_meshMakeEdge( GLUmesh *mesh )
+{
+ GLUvertex *newVertex1= allocVertex();
+ GLUvertex *newVertex2= allocVertex();
+ GLUface *newFace= allocFace();
+ GLUhalfEdge *e;
+
+ /* if any one is null then all get freed */
+ if (newVertex1 == NULL || newVertex2 == NULL || newFace == NULL) {
+ if (newVertex1 != NULL) memFree(newVertex1);
+ if (newVertex2 != NULL) memFree(newVertex2);
+ if (newFace != NULL) memFree(newFace);
+ return NULL;
+ }
+
+ e = MakeEdge( &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;
+}
+
+
+/* __gl_meshSplice( 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 __gl_meshSplice( GLUhalfEdge *eOrg, GLUhalfEdge *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( eDst->Org, eOrg->Org );
+ }
+ if( eDst->Lface != eOrg->Lface ) {
+ /* We are connecting two disjoint loops -- destroy eDst->Lface */
+ joiningLoops = TRUE;
+ KillFace( eDst->Lface, eOrg->Lface );
+ }
+
+ /* Change the edge structure */
+ Splice( eDst, eOrg );
+
+ if( ! joiningVertices ) {
+ GLUvertex *newVertex= allocVertex();
+ 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 ) {
+ GLUface *newFace= allocFace();
+ 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;
+}
+
+
+/* __gl_meshDelete( 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 __gl_meshSplice
+ * plus a few calls to memFree, but this would allocate and delete
+ * unnecessary vertices and faces.
+ */
+int __gl_meshDelete( GLUhalfEdge *eDel )
+{
+ GLUhalfEdge *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( eDel->Lface, eDel->Rface );
+ }
+
+ if( eDel->Onext == eDel ) {
+ KillVertex( 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 ) {
+ GLUface *newFace= allocFace();
+ 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( eDelSym->Org, NULL );
+ KillFace( 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( 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.
+ */
+
+
+/* __gl_meshAddEdgeVertex( 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.
+ */
+GLUhalfEdge *__gl_meshAddEdgeVertex( GLUhalfEdge *eOrg )
+{
+ GLUhalfEdge *eNewSym;
+ GLUhalfEdge *eNew = MakeEdge( 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;
+ {
+ GLUvertex *newVertex= allocVertex();
+ if (newVertex == NULL) return NULL;
+
+ MakeVertex( newVertex, eNewSym, eNew->Org );
+ }
+ eNew->Lface = eNewSym->Lface = eOrg->Lface;
+
+ return eNew;
+}
+
+
+/* __gl_meshSplitEdge( 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.
+ */
+GLUhalfEdge *__gl_meshSplitEdge( GLUhalfEdge *eOrg )
+{
+ GLUhalfEdge *eNew;
+ GLUhalfEdge *tempHalfEdge= __gl_meshAddEdgeVertex( 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;
+}
+
+
+/* __gl_meshConnect( 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.
+ */
+GLUhalfEdge *__gl_meshConnect( GLUhalfEdge *eOrg, GLUhalfEdge *eDst )
+{
+ GLUhalfEdge *eNewSym;
+ int joiningLoops = FALSE;
+ GLUhalfEdge *eNew = MakeEdge( 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( 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 ) {
+ GLUface *newFace= allocFace();
+ 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 **********************/
+
+/* __gl_meshZapFace( 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 __gl_meshZapFace( GLUface *fZap )
+{
+ GLUhalfEdge *eStart = fZap->anEdge;
+ GLUhalfEdge *e, *eNext, *eSym;
+ GLUface *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 __gl_MeshDelete above */
+
+ if( e->Onext == e ) {
+ KillVertex( 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( 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( e );
+ }
+ } while( e != eStart );
+
+ /* delete from circular doubly-linked list */
+ fPrev = fZap->prev;
+ fNext = fZap->next;
+ fNext->prev = fPrev;
+ fPrev->next = fNext;
+
+ memFree( fZap );
+}
+
+
+/* __gl_meshNewMesh() creates a new mesh with no edges, no vertices,
+ * and no loops (what we usually call a "face").
+ */
+GLUmesh *__gl_meshNewMesh( void )
+{
+ GLUvertex *v;
+ GLUface *f;
+ GLUhalfEdge *e;
+ GLUhalfEdge *eSym;
+ GLUmesh *mesh = (GLUmesh *)memAlloc( sizeof( GLUmesh ));
+ if (mesh == NULL) {
+ return NULL;
+ }
+
+ v = &mesh->vHead;
+ f = &mesh->fHead;
+ e = &mesh->eHead;
+ eSym = &mesh->eHeadSym;
+
+ v->next = v->prev = v;
+ v->anEdge = NULL;
+ v->data = NULL;
+
+ f->next = f->prev = f;
+ f->anEdge = NULL;
+ f->data = 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;
+}
+
+
+/* __gl_meshUnion( mesh1, mesh2 ) forms the union of all structures in
+ * both meshes, and returns the new mesh (the old meshes are destroyed).
+ */
+GLUmesh *__gl_meshUnion( GLUmesh *mesh1, GLUmesh *mesh2 )
+{
+ GLUface *f1 = &mesh1->fHead;
+ GLUvertex *v1 = &mesh1->vHead;
+ GLUhalfEdge *e1 = &mesh1->eHead;
+ GLUface *f2 = &mesh2->fHead;
+ GLUvertex *v2 = &mesh2->vHead;
+ GLUhalfEdge *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;
+ }
+
+ memFree( mesh2 );
+ return mesh1;
+}
+
+
+#ifdef DELETE_BY_ZAPPING
+
+/* __gl_meshDeleteMesh( mesh ) will free all storage for any valid mesh.
+ */
+void __gl_meshDeleteMesh( GLUmesh *mesh )
+{
+ GLUface *fHead = &mesh->fHead;
+
+ while( fHead->next != fHead ) {
+ __gl_meshZapFace( fHead->next );
+ }
+ assert( mesh->vHead.next == &mesh->vHead );
+
+ memFree( mesh );
+}
+
+#else
+
+/* __gl_meshDeleteMesh( mesh ) will free all storage for any valid mesh.
+ */
+void __gl_meshDeleteMesh( GLUmesh *mesh )
+{
+ GLUface *f, *fNext;
+ GLUvertex *v, *vNext;
+ GLUhalfEdge *e, *eNext;
+
+ for( f = mesh->fHead.next; f != &mesh->fHead; f = fNext ) {
+ fNext = f->next;
+ memFree( f );
+ }
+
+ for( v = mesh->vHead.next; v != &mesh->vHead; v = vNext ) {
+ vNext = v->next;
+ memFree( v );
+ }
+
+ for( e = mesh->eHead.next; e != &mesh->eHead; e = eNext ) {
+ /* One call frees both e and e->Sym (see EdgePair above) */
+ eNext = e->next;
+ memFree( e );
+ }
+
+ memFree( mesh );
+}
+
+#endif
+
+#ifndef NDEBUG
+
+/* __gl_meshCheckMesh( mesh ) checks a mesh for self-consistency.
+ */
+void __gl_meshCheckMesh( GLUmesh *mesh )
+{
+ GLUface *fHead = &mesh->fHead;
+ GLUvertex *vHead = &mesh->vHead;
+ GLUhalfEdge *eHead = &mesh->eHead;
+ GLUface *f, *fPrev;
+ GLUvertex *v, *vPrev;
+ GLUhalfEdge *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 && f->data == 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 && v->data == 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