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+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+/*
+ * mesher.c++
+ *
+ * $Date: 2001/03/17 00:25:41 $ $Revision: 1.1 $
+ * $Header: /home/krh/git/sync/mesa-cvs-repo/Mesa/src/glu/sgi/libnurbs/internals/mesher.cc,v 1.1 2001/03/17 00:25:41 brianp Exp $
+ */
+
+#include "glimports.h"
+#include "myassert.h"
+#include "mystdio.h"
+#include "mesher.h"
+#include "gridvertex.h"
+#include "gridtrimvertex.h"
+#include "jarcloc.h"
+#include "gridline.h"
+#include "trimline.h"
+#include "uarray.h"
+#include "backend.h"
+
+
+const float Mesher::ZERO = 0.0;
+
+Mesher::Mesher( Backend& b )
+ : backend( b ),
+ p( sizeof( GridTrimVertex ), 100, "GridTrimVertexPool" )
+{
+ stacksize = 0;
+ vdata = 0;
+ lastedge = 0; //needed to prevent purify UMR
+}
+
+Mesher::~Mesher( void )
+{
+ if( vdata ) delete[] vdata;
+}
+
+void
+Mesher::init( unsigned int npts )
+{
+ p.clear();
+ if( stacksize < npts ) {
+ stacksize = 2 * npts;
+ if( vdata ) delete[] vdata;
+ vdata = new GridTrimVertex_p[stacksize];
+ }
+}
+
+inline void
+Mesher::push( GridTrimVertex *gt )
+{
+ assert( itop+1 != stacksize );
+ vdata[++itop] = gt;
+}
+
+inline void
+Mesher::pop( long )
+{
+}
+
+inline void
+Mesher::openMesh()
+{
+ backend.bgntmesh( "addedge" );
+}
+
+inline void
+Mesher::closeMesh()
+{
+ backend.endtmesh();
+}
+
+inline void
+Mesher::swapMesh()
+{
+ backend.swaptmesh();
+}
+
+inline void
+Mesher::clearStack()
+{
+ itop = -1;
+ last[0] = 0;
+}
+
+void
+Mesher::finishLower( GridTrimVertex *gtlower )
+{
+ for( push(gtlower);
+ nextlower( gtlower=new(p) GridTrimVertex );
+ push(gtlower) )
+ addLower();
+ addLast();
+}
+
+void
+Mesher::finishUpper( GridTrimVertex *gtupper )
+{
+ for( push(gtupper);
+ nextupper( gtupper=new(p) GridTrimVertex );
+ push(gtupper) )
+ addUpper();
+ addLast();
+}
+
+void
+Mesher::mesh( void )
+{
+ GridTrimVertex *gtlower, *gtupper;
+
+ Hull::init( );
+ nextupper( gtupper = new(p) GridTrimVertex );
+ nextlower( gtlower = new(p) GridTrimVertex );
+
+ clearStack();
+ openMesh();
+ push(gtupper);
+
+ nextupper( gtupper = new(p) GridTrimVertex );
+ nextlower( gtlower );
+
+ assert( gtupper->t && gtlower->t );
+
+ if( gtupper->t->param[0] < gtlower->t->param[0] ) {
+ push(gtupper);
+ lastedge = 1;
+ if( nextupper( gtupper=new(p) GridTrimVertex ) == 0 ) {
+ finishLower(gtlower);
+ return;
+ }
+ } else if( gtupper->t->param[0] > gtlower->t->param[0] ) {
+ push(gtlower);
+ lastedge = 0;
+ if( nextlower( gtlower=new(p) GridTrimVertex ) == 0 ) {
+ finishUpper(gtupper);
+ return;
+ }
+ } else {
+ if( lastedge == 0 ) {
+ push(gtupper);
+ lastedge = 1;
+ if( nextupper(gtupper=new(p) GridTrimVertex) == 0 ) {
+ finishLower(gtlower);
+ return;
+ }
+ } else {
+ push(gtlower);
+ lastedge = 0;
+ if( nextlower( gtlower=new(p) GridTrimVertex ) == 0 ) {
+ finishUpper(gtupper);
+ return;
+ }
+ }
+ }
+
+ while ( 1 ) {
+ if( gtupper->t->param[0] < gtlower->t->param[0] ) {
+ push(gtupper);
+ addUpper();
+ if( nextupper( gtupper=new(p) GridTrimVertex ) == 0 ) {
+ finishLower(gtlower);
+ return;
+ }
+ } else if( gtupper->t->param[0] > gtlower->t->param[0] ) {
+ push(gtlower);
+ addLower();
+ if( nextlower( gtlower=new(p) GridTrimVertex ) == 0 ) {
+ finishUpper(gtupper);
+ return;
+ }
+ } else {
+ if( lastedge == 0 ) {
+ push(gtupper);
+ addUpper();
+ if( nextupper( gtupper=new(p) GridTrimVertex ) == 0 ) {
+ finishLower(gtlower);
+ return;
+ }
+ } else {
+ push(gtlower);
+ addLower();
+ if( nextlower( gtlower=new(p) GridTrimVertex ) == 0 ) {
+ finishUpper(gtupper);
+ return;
+ }
+ }
+ }
+ }
+}
+
+inline int
+Mesher::isCcw( int ilast )
+{
+ REAL area = det3( vdata[ilast]->t, vdata[itop-1]->t, vdata[itop-2]->t );
+ return (area < ZERO) ? 0 : 1;
+}
+
+inline int
+Mesher::isCw( int ilast )
+{
+ REAL area = det3( vdata[ilast]->t, vdata[itop-1]->t, vdata[itop-2]->t );
+ return (area > -ZERO) ? 0 : 1;
+}
+
+inline int
+Mesher::equal( int x, int y )
+{
+ return( last[0] == vdata[x] && last[1] == vdata[y] );
+}
+
+inline void
+Mesher::copy( int x, int y )
+{
+ last[0] = vdata[x]; last[1] = vdata[y];
+}
+
+inline void
+Mesher::move( int x, int y )
+{
+ vdata[x] = vdata[y];
+}
+
+inline void
+Mesher::output( int x )
+{
+ backend.tmeshvert( vdata[x] );
+}
+
+/*---------------------------------------------------------------------------
+ * addedge - addedge an edge to the triangulation
+ *
+ * This code has been re-written to generate large triangle meshes
+ * from a monotone polygon. Although smaller triangle meshes
+ * could be generated faster and with less code, larger meshes
+ * actually give better SYSTEM performance. This is because
+ * vertices are processed in the backend slower than they are
+ * generated by this code and any decrease in the number of vertices
+ * results in a decrease in the time spent in the backend.
+ *---------------------------------------------------------------------------
+ */
+
+void
+Mesher::addLast( )
+{
+ register int ilast = itop;
+
+ if( lastedge == 0 ) {
+ if( equal( 0, 1 ) ) {
+ output( ilast );
+ swapMesh();
+ for( register int i = 2; i < ilast; i++ ) {
+ swapMesh();
+ output( i );
+ }
+ copy( ilast, ilast-1 );
+ } else if( equal( ilast-2, ilast-1) ) {
+ swapMesh();
+ output( ilast );
+ for( register int i = ilast-3; i >= 0; i-- ) {
+ output( i );
+ swapMesh();
+ }
+ copy( 0, ilast );
+ } else {
+ closeMesh(); openMesh();
+ output( ilast );
+ output( 0 );
+ for( register int i = 1; i < ilast; i++ ) {
+ swapMesh();
+ output( i );
+ }
+ copy( ilast, ilast-1 );
+ }
+ } else {
+ if( equal( 1, 0) ) {
+ swapMesh();
+ output( ilast );
+ for( register int i = 2; i < ilast; i++ ) {
+ output( i );
+ swapMesh();
+ }
+ copy( ilast-1, ilast );
+ } else if( equal( ilast-1, ilast-2) ) {
+ output( ilast );
+ swapMesh();
+ for( register int i = ilast-3; i >= 0; i-- ) {
+ swapMesh();
+ output( i );
+ }
+ copy( ilast, 0 );
+ } else {
+ closeMesh(); openMesh();
+ output( 0 );
+ output( ilast );
+ for( register int i = 1; i < ilast; i++ ) {
+ output( i );
+ swapMesh();
+ }
+ copy( ilast-1, ilast );
+ }
+ }
+ closeMesh();
+ //for( register long k=0; k<=ilast; k++ ) pop( k );
+}
+
+void
+Mesher::addUpper( )
+{
+ register int ilast = itop;
+
+ if( lastedge == 0 ) {
+ if( equal( 0, 1 ) ) {
+ output( ilast );
+ swapMesh();
+ for( register int i = 2; i < ilast; i++ ) {
+ swapMesh();
+ output( i );
+ }
+ copy( ilast, ilast-1 );
+ } else if( equal( ilast-2, ilast-1) ) {
+ swapMesh();
+ output( ilast );
+ for( register int i = ilast-3; i >= 0; i-- ) {
+ output( i );
+ swapMesh();
+ }
+ copy( 0, ilast );
+ } else {
+ closeMesh(); openMesh();
+ output( ilast );
+ output( 0 );
+ for( register int i = 1; i < ilast; i++ ) {
+ swapMesh();
+ output( i );
+ }
+ copy( ilast, ilast-1 );
+ }
+ lastedge = 1;
+ //for( register long k=0; k<ilast-1; k++ ) pop( k );
+ move( 0, ilast-1 );
+ move( 1, ilast );
+ itop = 1;
+ } else {
+ if( ! isCcw( ilast ) ) return;
+ do {
+ itop--;
+ } while( (itop > 1) && isCcw( ilast ) );
+
+ if( equal( ilast-1, ilast-2 ) ) {
+ output( ilast );
+ swapMesh();
+ for( register int i=ilast-3; i>=itop-1; i-- ) {
+ swapMesh();
+ output( i );
+ }
+ copy( ilast, itop-1 );
+ } else if( equal( itop, itop-1 ) ) {
+ swapMesh();
+ output( ilast );
+ for( register int i = itop+1; i < ilast; i++ ) {
+ output( i );
+ swapMesh();
+ }
+ copy( ilast-1, ilast );
+ } else {
+ closeMesh(); openMesh();
+ output( ilast );
+ output( ilast-1 );
+ for( register int i=ilast-2; i>=itop-1; i-- ) {
+ swapMesh();
+ output( i );
+ }
+ copy( ilast, itop-1 );
+ }
+ //for( register int k=itop; k<ilast; k++ ) pop( k );
+ move( itop, ilast );
+ }
+}
+
+void
+Mesher::addLower()
+{
+ register int ilast = itop;
+
+ if( lastedge == 1 ) {
+ if( equal( 1, 0) ) {
+ swapMesh();
+ output( ilast );
+ for( register int i = 2; i < ilast; i++ ) {
+ output( i );
+ swapMesh();
+ }
+ copy( ilast-1, ilast );
+ } else if( equal( ilast-1, ilast-2) ) {
+ output( ilast );
+ swapMesh();
+ for( register int i = ilast-3; i >= 0; i-- ) {
+ swapMesh();
+ output( i );
+ }
+ copy( ilast, 0 );
+ } else {
+ closeMesh(); openMesh();
+ output( 0 );
+ output( ilast );
+ for( register int i = 1; i < ilast; i++ ) {
+ output( i );
+ swapMesh();
+ }
+ copy( ilast-1, ilast );
+ }
+
+ lastedge = 0;
+ //for( register long k=0; k<ilast-1; k++ ) pop( k );
+ move( 0, ilast-1 );
+ move( 1, ilast );
+ itop = 1;
+ } else {
+ if( ! isCw( ilast ) ) return;
+ do {
+ itop--;
+ } while( (itop > 1) && isCw( ilast ) );
+
+ if( equal( ilast-2, ilast-1) ) {
+ swapMesh();
+ output( ilast );
+ for( register int i=ilast-3; i>=itop-1; i--) {
+ output( i );
+ swapMesh( );
+ }
+ copy( itop-1, ilast );
+ } else if( equal( itop-1, itop) ) {
+ output( ilast );
+ swapMesh();
+ for( register int i=itop+1; i<ilast; i++ ) {
+ swapMesh( );
+ output( i );
+ }
+ copy( ilast, ilast-1 );
+ } else {
+ closeMesh(); openMesh();
+ output( ilast-1 );
+ output( ilast );
+ for( register int i=ilast-2; i>=itop-1; i-- ) {
+ output( i );
+ swapMesh( );
+ }
+ copy( itop-1, ilast );
+ }
+ //for( register int k=itop; k<ilast; k++ ) pop( k );
+ move( itop, ilast );
+ }
+}
+
+
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