src/glu/sgi/libnurbs/internals/splitarcs.cc

   1 /*
   2 ** License Applicability. Except to the extent portions of this file are
   3 ** made subject to an alternative license as permitted in the SGI Free
   4 ** Software License B, Version 1.1 (the "License"), the contents of this
   5 ** file are subject only to the provisions of the License. You may not use
   6 ** this file except in compliance with the License. You may obtain a copy
   7 ** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
   8 ** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
   9 **
  10 ** http://oss.sgi.com/projects/FreeB
  11 **
  12 ** Note that, as provided in the License, the Software is distributed on an
  13 ** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
  14 ** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
  15 ** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
  16 ** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
  17 **
  18 ** Original Code. The Original Code is: OpenGL Sample Implementation,
  19 ** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
  20 ** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
  21 ** Copyright in any portions created by third parties is as indicated
  22 ** elsewhere herein. All Rights Reserved.
  23 **
  24 ** Additional Notice Provisions: The application programming interfaces
  25 ** established by SGI in conjunction with the Original Code are The
  26 ** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
  27 ** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
  28 ** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
  29 ** Window System(R) (Version 1.3), released October 19, 1998. This software
  30 ** was created using the OpenGL(R) version 1.2.1 Sample Implementation
  31 ** published by SGI, but has not been independently verified as being
  32 ** compliant with the OpenGL(R) version 1.2.1 Specification.
  33 */
  34
  35 /*
  36  * splitarcs.c++
  37  *
  38  */
  39
  40 #include "glimports.h"
  41 #include "myassert.h"
  42 #include "mysetjmp.h"
  43 #include "mystdio.h"
  44 #include "subdivider.h"
  45 #include "arcsorter.h"
  46 #include "arc.h"
  47 #include "bin.h"
  48
  49 /* local preprocessor definitions */
  50 #define MAXARCS 10
  51
  52 /*----------------------------------------------------------------------------
  53  * Subdivider::split - split trim regions in source bin by line (param == value).
  54  *----------------------------------------------------------------------------
  55  */
  56
  57 void
  58 Subdivider::split( Bin& bin, Bin& left, Bin& right, int param, REAL value )
  59 {
  60     Bin intersections, unknown;
  61
  62     partition( bin, left, intersections, right, unknown, param, value );
  63
  64     int count = intersections.numarcs();
  65     if( count % 2 ) {
  66 #ifndef NDEBUG
  67         left.show( "left" );
  68         intersections.show( "intersections" );
  69         right.show( "right" );
  70 #endif
  71         ::mylongjmp( jumpbuffer, 29 );
  72     }
  73
  74     Arc_ptr arclist[MAXARCS], *list;
  75     if( count >= MAXARCS ) {
  76         list = new Arc_ptr[count];
  77     } else {
  78         list = arclist;
  79     }
  80
  81     Arc_ptr jarc, *last, *lptr;
  82     for( last = list; (jarc=intersections.removearc()) != NULL; last++ )
  83         *last = jarc;
  84
  85     if( param == 0 ) { /* sort into increasing t order */
  86         ArcSdirSorter sorter(*this);
  87         sorter.qsort( list, count );
  88
  89         //::qsort ((void *)list, count, sizeof(Arc_ptr), (cmpfunc)compare_s);
  90         for( lptr=list; lptr<last; lptr+=2 )
  91             check_s ( lptr[0], lptr[1] );
  92         for( lptr=list; lptr<last; lptr+=2 )
  93             join_s ( left, right, lptr[0], lptr[1] );
  94         for( lptr=list; lptr != last; lptr++ ) {
  95             if( ((*lptr)->head()[0] <= value) && ((*lptr)->tail()[0] <= value) )
  96                 left.addarc( *lptr  );
  97             else
  98                 right.addarc( *lptr  );
  99         }
 100     } else { /* sort into decreasing s order */
 101         ArcTdirSorter sorter(*this);
 102         sorter.qsort( list, count );
 103         //::qsort ((void *)list, count, sizeof(Arc_ptr), (cmpfunc)compare_t);
 104         for( lptr=list; lptr<last; lptr+=2 )
 105             check_t ( lptr[0], lptr[1] );
 106         for( lptr=list; lptr<last; lptr+=2 )
 107             join_t ( left, right, lptr[0], lptr[1] );
 108         for( lptr=list; lptr != last; lptr++ ) {
 109             if( ((*lptr)->head()[1] <= value) && ((*lptr)->tail()[1] <= value) )
 110                 left.addarc( *lptr  );
 111             else
 112                 right.addarc( *lptr  );
 113         }
 114     }
 115
 116     if( list != arclist ) delete[] list;
 117     unknown.adopt();
 118 }
 119
 120
 121 void
 122 Subdivider::check_s( Arc_ptr jarc1, Arc_ptr jarc2 )
 123 {
 124     assert( jarc1->check( ) != 0 );
 125     assert( jarc2->check( ) != 0 );
 126     assert( jarc1->next->check( ) != 0 );
 127     assert( jarc2->next->check( ) != 0 );
 128     assert( jarc1 != jarc2 );
 129
 130     /* XXX - if these assertions fail, it is due to user error or
 131              undersampling */
 132     if( ! ( jarc1->tail()[0] < (jarc1)->head()[0] ) ) {
 133 #ifndef NDEBUG
 134         _glu_dprintf( "s difference %f\n",  (jarc1)->tail()[0] - (jarc1)->head()[0] );
 135 #endif
 136         ::mylongjmp( jumpbuffer, 28 );
 137     }
 138
 139     if( ! ( jarc2->tail()[0] > (jarc2)->head()[0] ) ) {
 140 #ifndef NDEBUG
 141         _glu_dprintf( "s difference %f\n",  (jarc2)->tail()[0] - (jarc2)->head()[0] );
 142 #endif
 143         ::mylongjmp( jumpbuffer, 28 );
 144     }
 145 }
 146
 147 inline void
 148 Subdivider::link( Arc_ptr jarc1, Arc_ptr jarc2, Arc_ptr up, Arc_ptr down )
 149 {
 150     up->nuid = down->nuid = 0;          // XXX
 151
 152     up->next = jarc2;
 153     down->next = jarc1;
 154     up->prev = jarc1->prev;
 155     down->prev = jarc2->prev;
 156
 157     down->next->prev = down;
 158     up->next->prev = up;
 159     down->prev->next = down;
 160     up->prev->next = up;
 161 }
 162
 163 inline void
 164 Subdivider::simple_link( Arc_ptr jarc1, Arc_ptr jarc2 )
 165 {
 166     Arc_ptr tmp = jarc2->prev;
 167     jarc2->prev = jarc1->prev;
 168     jarc1->prev = tmp;
 169     jarc2->prev->next = jarc2;
 170     jarc1->prev->next = jarc1;
 171 }
 172
 173
 174 /*----------------------------------------------------------------------------
 175  * join - add a pair of oppositely directed jordan arcs between two arcs
 176  *----------------------------------------------------------------------------
 177  */
 178
 179 void
 180 Subdivider::join_s( Bin& left, Bin& right, Arc_ptr jarc1, Arc_ptr jarc2 )
 181 {
 182     assert( jarc1->check( ) != 0);
 183     assert( jarc2->check( ) != 0);
 184     assert( jarc1 != jarc2 );
 185
 186     if( ! jarc1->getitail() )
 187         jarc1 = jarc1->next;
 188
 189     if( ! jarc2->getitail() )
 190         jarc2 = jarc2->next;
 191
 192     REAL s = jarc1->tail()[0];
 193     REAL t1 = jarc1->tail()[1];
 194     REAL t2 = jarc2->tail()[1];
 195
 196     if( t1 == t2 ) {
 197         simple_link( jarc1, jarc2 );
 198     } else {
 199         Arc_ptr newright = new(arcpool) Arc( arc_right, 0 );
 200         Arc_ptr newleft = new(arcpool) Arc( arc_left, 0 );
 201         assert( t1 < t2 );
 202         if( isBezierArcType() ) {
 203             arctessellator.bezier( newright, s, s, t1, t2 );
 204             arctessellator.bezier( newleft, s, s, t2, t1 );
 205         } else {
 206             arctessellator.pwl_right( newright, s, t1, t2, stepsizes[0] );
 207             arctessellator.pwl_left( newleft, s, t2, t1, stepsizes[2] );
 208         }
 209         link( jarc1, jarc2, newright, newleft );
 210         left.addarc( newright  );
 211         right.addarc( newleft  );
 212     }
 213
 214     assert( jarc1->check( ) != 0 );
 215     assert( jarc2->check( ) != 0 );
 216     assert( jarc1->next->check( ) != 0);
 217     assert( jarc2->next->check( ) != 0);
 218 }
 219
 220 void
 221 Subdivider::check_t( Arc_ptr jarc1, Arc_ptr jarc2 )
 222 {
 223     assert( jarc1->check( ) != 0 );
 224     assert( jarc2->check( ) != 0 );
 225     assert( jarc1->next->check( ) != 0 );
 226     assert( jarc2->next->check( ) != 0 );
 227     assert( jarc1 != jarc2 );
 228
 229     /* XXX - if these assertions fail, it is due to user error or
 230              undersampling */
 231     if( ! ( jarc1->tail()[1] < (jarc1)->head()[1] ) ) {
 232 #ifndef NDEBUG
 233         _glu_dprintf( "t difference %f\n",  jarc1->tail()[1] - (jarc1)->head()[1] );
 234 #endif
 235         ::mylongjmp( jumpbuffer, 28 );
 236     }
 237
 238     if( ! ( jarc2->tail()[1] > (jarc2)->head()[1] ) ) {
 239 #ifndef NDEBUG
 240         _glu_dprintf( "t difference %f\n",  jarc2->tail()[1] - (jarc2)->head()[1] );
 241 #endif
 242         ::mylongjmp( jumpbuffer, 28 );
 243     }
 244 }
 245
 246 /*----------------------------------------------------------------------------
 247  * join_t - add a pair of oppositely directed jordan arcs between two arcs
 248  *----------------------------------------------------------------------------
 249  */
 250
 251 void
 252 Subdivider::join_t( Bin& bottom, Bin& top, Arc_ptr jarc1, Arc_ptr jarc2 )
 253 {
 254     assert( jarc1->check( ) != 0 );
 255     assert( jarc2->check( ) != 0 );
 256     assert( jarc1->next->check( ) != 0 );
 257     assert( jarc2->next->check( ) != 0 );
 258     assert( jarc1 != jarc2 );
 259
 260     if( ! jarc1->getitail() )
 261         jarc1 = jarc1->next;
 262
 263     if( ! jarc2->getitail() )
 264         jarc2 = jarc2->next;
 265
 266     REAL s1 = jarc1->tail()[0];
 267     REAL s2 = jarc2->tail()[0];
 268     REAL t  = jarc1->tail()[1];
 269
 270     if( s1 == s2 ) {
 271         simple_link( jarc1, jarc2 );
 272     } else {
 273         Arc_ptr newtop = new(arcpool) Arc( arc_top, 0 );
 274         Arc_ptr newbot = new(arcpool) Arc( arc_bottom, 0 );
 275         assert( s1 > s2 );
 276         if( isBezierArcType() ) {
 277             arctessellator.bezier( newtop, s1, s2, t, t );
 278             arctessellator.bezier( newbot, s2, s1, t, t );
 279         } else {
 280             arctessellator.pwl_top( newtop, t, s1, s2, stepsizes[1] );
 281             arctessellator.pwl_bottom( newbot, t, s2, s1, stepsizes[3] );
 282         }
 283         link( jarc1, jarc2, newtop, newbot );
 284         bottom.addarc( newtop  );
 285         top.addarc( newbot  );
 286     }
 287
 288     assert( jarc1->check( ) != 0 );
 289     assert( jarc2->check( ) != 0 );
 290     assert( jarc1->next->check( ) != 0 );
 291     assert( jarc2->next->check( ) != 0 );
 292 }
 293