dll/opengl/glu32/src/libtess/tess.c

   1 /*
   2  * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
   3  * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice including the dates of first publication and
  13  * either this permission notice or a reference to
  14  * http://oss.sgi.com/projects/FreeB/
  15  * shall be included in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  21  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
  22  * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE.
  24  *
  25  * Except as contained in this notice, the name of Silicon Graphics, Inc.
  26  * shall not be used in advertising or otherwise to promote the sale, use or
  27  * other dealings in this Software without prior written authorization from
  28  * Silicon Graphics, Inc.
  29  */
  30 /*
  31 ** Author: Eric Veach, July 1994.
  32 **
  33 */
  34
  35 #include "gluos.h"
  36 #include <stddef.h>
  37 #include <assert.h>
  38 #include <setjmp.h>
  39 #include "memalloc.h"
  40 #include "tess.h"
  41 #include "mesh.h"
  42 #include "normal.h"
  43 #include "sweep.h"
  44 #include "tessmono.h"
  45 #include "render.h"
  46
  47 #define GLU_TESS_DEFAULT_TOLERANCE 0.0
  48 #define GLU_TESS_MESH           100112  /* void (*)(GLUmesh *mesh)          */
  49
  50 #ifndef TRUE
  51 #define TRUE 1
  52 #endif
  53 #ifndef FALSE
  54 #define FALSE 0
  55 #endif
  56
  57 /*ARGSUSED*/ static void GLAPIENTRY noBegin( GLenum type ) {}
  58 /*ARGSUSED*/ static void GLAPIENTRY noEdgeFlag( GLboolean boundaryEdge ) {}
  59 /*ARGSUSED*/ static void GLAPIENTRY noVertex( void *data ) {}
  60 /*ARGSUSED*/ static void GLAPIENTRY noEnd( void ) {}
  61 /*ARGSUSED*/ static void GLAPIENTRY noError( GLenum errnum ) {}
  62 /*ARGSUSED*/ static void GLAPIENTRY noCombine( GLdouble coords[3], void *data[4],
  63                                     GLfloat weight[4], void **dataOut ) {}
  64 /*ARGSUSED*/ static void GLAPIENTRY noMesh( GLUmesh *mesh ) {}
  65
  66
  67 /*ARGSUSED*/ void GLAPIENTRY __gl_noBeginData( GLenum type,
  68                                              void *polygonData ) {}
  69 /*ARGSUSED*/ void GLAPIENTRY __gl_noEdgeFlagData( GLboolean boundaryEdge,
  70                                        void *polygonData ) {}
  71 /*ARGSUSED*/ void GLAPIENTRY __gl_noVertexData( void *data,
  72                                               void *polygonData ) {}
  73 /*ARGSUSED*/ void GLAPIENTRY __gl_noEndData( void *polygonData ) {}
  74 /*ARGSUSED*/ void GLAPIENTRY __gl_noErrorData( GLenum errnum,
  75                                              void *polygonData ) {}
  76 /*ARGSUSED*/ void GLAPIENTRY __gl_noCombineData( GLdouble coords[3],
  77                                                void *data[4],
  78                                                GLfloat weight[4],
  79                                                void **outData,
  80                                                void *polygonData ) {}
  81
  82 /* Half-edges are allocated in pairs (see mesh.c) */
  83 typedef struct { GLUhalfEdge e, eSym; } EdgePair;
  84
  85 #undef  MAX
  86 #define MAX(a,b)        ((a) > (b) ? (a) : (b))
  87 #define MAX_FAST_ALLOC  (MAX(sizeof(EdgePair), \
  88                          MAX(sizeof(GLUvertex),sizeof(GLUface))))
  89
  90
  91 GLUtesselator * GLAPIENTRY
  92 gluNewTess( void )
  93 {
  94   GLUtesselator *tess;
  95
  96   /* Only initialize fields which can be changed by the api.  Other fields
  97    * are initialized where they are used.
  98    */
  99
 100   if (memInit( MAX_FAST_ALLOC ) == 0) {
 101      return 0;                  /* out of memory */
 102   }
 103   tess = (GLUtesselator *)memAlloc( sizeof( GLUtesselator ));
 104   if (tess == NULL) {
 105      return 0;                  /* out of memory */
 106   }
 107
 108   tess->state = T_DORMANT;
 109
 110   tess->normal[0] = 0;
 111   tess->normal[1] = 0;
 112   tess->normal[2] = 0;
 113
 114   tess->relTolerance = GLU_TESS_DEFAULT_TOLERANCE;
 115   tess->windingRule = GLU_TESS_WINDING_ODD;
 116   tess->flagBoundary = FALSE;
 117   tess->boundaryOnly = FALSE;
 118
 119   tess->callBegin = &noBegin;
 120   tess->callEdgeFlag = &noEdgeFlag;
 121   tess->callVertex = &noVertex;
 122   tess->callEnd = &noEnd;
 123
 124   tess->callError = &noError;
 125   tess->callCombine = &noCombine;
 126   tess->callMesh = &noMesh;
 127
 128   tess->callBeginData= &__gl_noBeginData;
 129   tess->callEdgeFlagData= &__gl_noEdgeFlagData;
 130   tess->callVertexData= &__gl_noVertexData;
 131   tess->callEndData= &__gl_noEndData;
 132   tess->callErrorData= &__gl_noErrorData;
 133   tess->callCombineData= &__gl_noCombineData;
 134
 135   tess->polygonData= NULL;
 136
 137   return tess;
 138 }
 139
 140 static void MakeDormant( GLUtesselator *tess )
 141 {
 142   /* Return the tessellator to its original dormant state. */
 143
 144   if( tess->mesh != NULL ) {
 145     __gl_meshDeleteMesh( tess->mesh );
 146   }
 147   tess->state = T_DORMANT;
 148   tess->lastEdge = NULL;
 149   tess->mesh = NULL;
 150 }
 151
 152 #define RequireState( tess, s )   if( tess->state != s ) GotoState(tess,s)
 153
 154 static void GotoState( GLUtesselator *tess, enum TessState newState )
 155 {
 156   while( tess->state != newState ) {
 157     /* We change the current state one level at a time, to get to
 158      * the desired state.
 159      */
 160     if( tess->state < newState ) {
 161       switch( tess->state ) {
 162       case T_DORMANT:
 163         CALL_ERROR_OR_ERROR_DATA( GLU_TESS_MISSING_BEGIN_POLYGON );
 164         gluTessBeginPolygon( tess, NULL );
 165         break;
 166       case T_IN_POLYGON:
 167         CALL_ERROR_OR_ERROR_DATA( GLU_TESS_MISSING_BEGIN_CONTOUR );
 168         gluTessBeginContour( tess );
 169         break;
 170       default:
 171          ;
 172       }
 173     } else {
 174       switch( tess->state ) {
 175       case T_IN_CONTOUR:
 176         CALL_ERROR_OR_ERROR_DATA( GLU_TESS_MISSING_END_CONTOUR );
 177         gluTessEndContour( tess );
 178         break;
 179       case T_IN_POLYGON:
 180         CALL_ERROR_OR_ERROR_DATA( GLU_TESS_MISSING_END_POLYGON );
 181         /* gluTessEndPolygon( tess ) is too much work! */
 182         MakeDormant( tess );
 183         break;
 184       default:
 185          ;
 186       }
 187     }
 188   }
 189 }
 190
 191
 192 void GLAPIENTRY
 193 gluDeleteTess( GLUtesselator *tess )
 194 {
 195   RequireState( tess, T_DORMANT );
 196   memFree( tess );
 197 }
 198
 199
 200 void GLAPIENTRY
 201 gluTessProperty( GLUtesselator *tess, GLenum which, GLdouble value )
 202 {
 203   GLenum windingRule;
 204
 205   switch( which ) {
 206   case GLU_TESS_TOLERANCE:
 207     if( value < 0.0 || value > 1.0 ) break;
 208     tess->relTolerance = value;
 209     return;
 210
 211   case GLU_TESS_WINDING_RULE:
 212     windingRule = (GLenum) value;
 213     if( windingRule != value ) break;   /* not an integer */
 214
 215     switch( windingRule ) {
 216     case GLU_TESS_WINDING_ODD:
 217     case GLU_TESS_WINDING_NONZERO:
 218     case GLU_TESS_WINDING_POSITIVE:
 219     case GLU_TESS_WINDING_NEGATIVE:
 220     case GLU_TESS_WINDING_ABS_GEQ_TWO:
 221       tess->windingRule = windingRule;
 222       return;
 223     default:
 224       break;
 225     }
 226
 227   case GLU_TESS_BOUNDARY_ONLY:
 228     tess->boundaryOnly = (value != 0);
 229     return;
 230
 231   default:
 232     CALL_ERROR_OR_ERROR_DATA( GLU_INVALID_ENUM );
 233     return;
 234   }
 235   CALL_ERROR_OR_ERROR_DATA( GLU_INVALID_VALUE );
 236 }
 237
 238 /* Returns tessellator property */
 239 void GLAPIENTRY
 240 gluGetTessProperty( GLUtesselator *tess, GLenum which, GLdouble *value )
 241 {
 242    switch (which) {
 243    case GLU_TESS_TOLERANCE:
 244       /* tolerance should be in range [0..1] */
 245       assert(0.0 <= tess->relTolerance && tess->relTolerance <= 1.0);
 246       *value= tess->relTolerance;
 247       break;
 248    case GLU_TESS_WINDING_RULE:
 249       assert(tess->windingRule == GLU_TESS_WINDING_ODD ||
 250              tess->windingRule == GLU_TESS_WINDING_NONZERO ||
 251              tess->windingRule == GLU_TESS_WINDING_POSITIVE ||
 252              tess->windingRule == GLU_TESS_WINDING_NEGATIVE ||
 253              tess->windingRule == GLU_TESS_WINDING_ABS_GEQ_TWO);
 254       *value= tess->windingRule;
 255       break;
 256    case GLU_TESS_BOUNDARY_ONLY:
 257       assert(tess->boundaryOnly == TRUE || tess->boundaryOnly == FALSE);
 258       *value= tess->boundaryOnly;
 259       break;
 260    default:
 261       *value= 0.0;
 262       CALL_ERROR_OR_ERROR_DATA( GLU_INVALID_ENUM );
 263       break;
 264    }
 265 } /* gluGetTessProperty() */
 266
 267 void GLAPIENTRY
 268 gluTessNormal( GLUtesselator *tess, GLdouble x, GLdouble y, GLdouble z )
 269 {
 270   tess->normal[0] = x;
 271   tess->normal[1] = y;
 272   tess->normal[2] = z;
 273 }
 274
 275 void GLAPIENTRY
 276 gluTessCallback( GLUtesselator *tess, GLenum which, _GLUfuncptr fn)
 277 {
 278   switch( which ) {
 279   case GLU_TESS_BEGIN:
 280     tess->callBegin = (fn == NULL) ? &noBegin : (void (GLAPIENTRY *)(GLenum)) fn;
 281     return;
 282   case GLU_TESS_BEGIN_DATA:
 283     tess->callBeginData = (fn == NULL) ?
 284         &__gl_noBeginData : (void (GLAPIENTRY *)(GLenum, void *)) fn;
 285     return;
 286   case GLU_TESS_EDGE_FLAG:
 287     tess->callEdgeFlag = (fn == NULL) ? &noEdgeFlag :
 288                                         (void (GLAPIENTRY *)(GLboolean)) fn;
 289     /* If the client wants boundary edges to be flagged,
 290      * we render everything as separate triangles (no strips or fans).
 291      */
 292     tess->flagBoundary = (fn != NULL);
 293     return;
 294   case GLU_TESS_EDGE_FLAG_DATA:
 295     tess->callEdgeFlagData= (fn == NULL) ?
 296         &__gl_noEdgeFlagData : (void (GLAPIENTRY *)(GLboolean, void *)) fn;
 297     /* If the client wants boundary edges to be flagged,
 298      * we render everything as separate triangles (no strips or fans).
 299      */
 300     tess->flagBoundary = (fn != NULL);
 301     return;
 302   case GLU_TESS_VERTEX:
 303     tess->callVertex = (fn == NULL) ? &noVertex :
 304                                       (void (GLAPIENTRY *)(void *)) fn;
 305     return;
 306   case GLU_TESS_VERTEX_DATA:
 307     tess->callVertexData = (fn == NULL) ?
 308         &__gl_noVertexData : (void (GLAPIENTRY *)(void *, void *)) fn;
 309     return;
 310   case GLU_TESS_END:
 311     tess->callEnd = (fn == NULL) ? &noEnd : (void (GLAPIENTRY *)(void)) fn;
 312     return;
 313   case GLU_TESS_END_DATA:
 314     tess->callEndData = (fn == NULL) ? &__gl_noEndData :
 315                                        (void (GLAPIENTRY *)(void *)) fn;
 316     return;
 317   case GLU_TESS_ERROR:
 318     tess->callError = (fn == NULL) ? &noError : (void (GLAPIENTRY *)(GLenum)) fn;
 319     return;
 320   case GLU_TESS_ERROR_DATA:
 321     tess->callErrorData = (fn == NULL) ?
 322         &__gl_noErrorData : (void (GLAPIENTRY *)(GLenum, void *)) fn;
 323     return;
 324   case GLU_TESS_COMBINE:
 325     tess->callCombine = (fn == NULL) ? &noCombine :
 326         (void (GLAPIENTRY *)(GLdouble [3],void *[4], GLfloat [4], void ** )) fn;
 327     return;
 328   case GLU_TESS_COMBINE_DATA:
 329     tess->callCombineData = (fn == NULL) ? &__gl_noCombineData :
 330                                            (void (GLAPIENTRY *)(GLdouble [3],
 331                                                      void *[4],
 332                                                      GLfloat [4],
 333                                                      void **,
 334                                                      void *)) fn;
 335     return;
 336   case GLU_TESS_MESH:
 337     tess->callMesh = (fn == NULL) ? &noMesh : (void (GLAPIENTRY *)(GLUmesh *)) fn;
 338     return;
 339   default:
 340     CALL_ERROR_OR_ERROR_DATA( GLU_INVALID_ENUM );
 341     return;
 342   }
 343 }
 344
 345 static int AddVertex( GLUtesselator *tess, GLdouble coords[3], void *data )
 346 {
 347   GLUhalfEdge *e;
 348
 349   e = tess->lastEdge;
 350   if( e == NULL ) {
 351     /* Make a self-loop (one vertex, one edge). */
 352
 353     e = __gl_meshMakeEdge( tess->mesh );
 354     if (e == NULL) return 0;
 355     if ( !__gl_meshSplice( e, e->Sym ) ) return 0;
 356   } else {
 357     /* Create a new vertex and edge which immediately follow e
 358      * in the ordering around the left face.
 359      */
 360     if (__gl_meshSplitEdge( e ) == NULL) return 0;
 361     e = e->Lnext;
 362   }
 363
 364   /* The new vertex is now e->Org. */
 365   e->Org->data = data;
 366   e->Org->coords[0] = coords[0];
 367   e->Org->coords[1] = coords[1];
 368   e->Org->coords[2] = coords[2];
 369
 370   /* The winding of an edge says how the winding number changes as we
 371    * cross from the edge''s right face to its left face.  We add the
 372    * vertices in such an order that a CCW contour will add +1 to
 373    * the winding number of the region inside the contour.
 374    */
 375   e->winding = 1;
 376   e->Sym->winding = -1;
 377
 378   tess->lastEdge = e;
 379
 380   return 1;
 381 }
 382
 383
 384 static void CacheVertex( GLUtesselator *tess, GLdouble coords[3], void *data )
 385 {
 386   CachedVertex *v = &tess->cache[tess->cacheCount];
 387
 388   v->data = data;
 389   v->coords[0] = coords[0];
 390   v->coords[1] = coords[1];
 391   v->coords[2] = coords[2];
 392   ++tess->cacheCount;
 393 }
 394
 395
 396 static int EmptyCache( GLUtesselator *tess )
 397 {
 398   CachedVertex *v = tess->cache;
 399   CachedVertex *vLast;
 400
 401   tess->mesh = __gl_meshNewMesh();
 402   if (tess->mesh == NULL) return 0;
 403
 404   for( vLast = v + tess->cacheCount; v < vLast; ++v ) {
 405     if ( !AddVertex( tess, v->coords, v->data ) ) return 0;
 406   }
 407   tess->cacheCount = 0;
 408   tess->emptyCache = FALSE;
 409
 410   return 1;
 411 }
 412
 413
 414 void GLAPIENTRY
 415 gluTessVertex( GLUtesselator *tess, GLdouble coords[3], void *data )
 416 {
 417   int i, tooLarge = FALSE;
 418   GLdouble x, clamped[3];
 419
 420   RequireState( tess, T_IN_CONTOUR );
 421
 422   if( tess->emptyCache ) {
 423     if ( !EmptyCache( tess ) ) {
 424        CALL_ERROR_OR_ERROR_DATA( GLU_OUT_OF_MEMORY );
 425        return;
 426     }
 427     tess->lastEdge = NULL;
 428   }
 429   for( i = 0; i < 3; ++i ) {
 430     x = coords[i];
 431     if( x < - GLU_TESS_MAX_COORD ) {
 432       x = - GLU_TESS_MAX_COORD;
 433       tooLarge = TRUE;
 434     }
 435     if( x > GLU_TESS_MAX_COORD ) {
 436       x = GLU_TESS_MAX_COORD;
 437       tooLarge = TRUE;
 438     }
 439     clamped[i] = x;
 440   }
 441   if( tooLarge ) {
 442     CALL_ERROR_OR_ERROR_DATA( GLU_TESS_COORD_TOO_LARGE );
 443   }
 444
 445   if( tess->mesh == NULL ) {
 446     if( tess->cacheCount < TESS_MAX_CACHE ) {
 447       CacheVertex( tess, clamped, data );
 448       return;
 449     }
 450     if ( !EmptyCache( tess ) ) {
 451        CALL_ERROR_OR_ERROR_DATA( GLU_OUT_OF_MEMORY );
 452        return;
 453     }
 454   }
 455   if ( !AddVertex( tess, clamped, data ) ) {
 456        CALL_ERROR_OR_ERROR_DATA( GLU_OUT_OF_MEMORY );
 457   }
 458 }
 459
 460
 461 void GLAPIENTRY
 462 gluTessBeginPolygon( GLUtesselator *tess, void *data )
 463 {
 464   RequireState( tess, T_DORMANT );
 465
 466   tess->state = T_IN_POLYGON;
 467   tess->cacheCount = 0;
 468   tess->emptyCache = FALSE;
 469   tess->mesh = NULL;
 470
 471   tess->polygonData= data;
 472 }
 473
 474
 475 void GLAPIENTRY
 476 gluTessBeginContour( GLUtesselator *tess )
 477 {
 478   RequireState( tess, T_IN_POLYGON );
 479
 480   tess->state = T_IN_CONTOUR;
 481   tess->lastEdge = NULL;
 482   if( tess->cacheCount > 0 ) {
 483     /* Just set a flag so we don't get confused by empty contours
 484      * -- these can be generated accidentally with the obsolete
 485      * NextContour() interface.
 486      */
 487     tess->emptyCache = TRUE;
 488   }
 489 }
 490
 491
 492 void GLAPIENTRY
 493 gluTessEndContour( GLUtesselator *tess )
 494 {
 495   RequireState( tess, T_IN_CONTOUR );
 496   tess->state = T_IN_POLYGON;
 497 }
 498
 499 void GLAPIENTRY
 500 gluTessEndPolygon( GLUtesselator *tess )
 501 {
 502   GLUmesh *mesh;
 503
 504   if (setjmp(tess->env) != 0) {
 505      /* come back here if out of memory */
 506      CALL_ERROR_OR_ERROR_DATA( GLU_OUT_OF_MEMORY );
 507      return;
 508   }
 509
 510   RequireState( tess, T_IN_POLYGON );
 511   tess->state = T_DORMANT;
 512
 513   if( tess->mesh == NULL ) {
 514     if( ! tess->flagBoundary && tess->callMesh == &noMesh ) {
 515
 516       /* Try some special code to make the easy cases go quickly
 517        * (eg. convex polygons).  This code does NOT handle multiple contours,
 518        * intersections, edge flags, and of course it does not generate
 519        * an explicit mesh either.
 520        */
 521       if( __gl_renderCache( tess )) {
 522         tess->polygonData= NULL;
 523         return;
 524       }
 525     }
 526     if ( !EmptyCache( tess ) ) longjmp(tess->env,1); /* could've used a label*/
 527   }
 528
 529   /* Determine the polygon normal and project vertices onto the plane
 530    * of the polygon.
 531    */
 532   __gl_projectPolygon( tess );
 533
 534   /* __gl_computeInterior( tess ) computes the planar arrangement specified
 535    * by the given contours, and further subdivides this arrangement
 536    * into regions.  Each region is marked "inside" if it belongs
 537    * to the polygon, according to the rule given by tess->windingRule.
 538    * Each interior region is guaranteed be monotone.
 539    */
 540   if ( !__gl_computeInterior( tess ) ) {
 541      longjmp(tess->env,1);      /* could've used a label */
 542   }
 543
 544   mesh = tess->mesh;
 545   if( ! tess->fatalError ) {
 546     int rc = 1;
 547
 548     /* If the user wants only the boundary contours, we throw away all edges
 549      * except those which separate the interior from the exterior.
 550      * Otherwise we tessellate all the regions marked "inside".
 551      */
 552     if( tess->boundaryOnly ) {
 553       rc = __gl_meshSetWindingNumber( mesh, 1, TRUE );
 554     } else {
 555       rc = __gl_meshTessellateInterior( mesh );
 556     }
 557     if (rc == 0) longjmp(tess->env,1);  /* could've used a label */
 558
 559     __gl_meshCheckMesh( mesh );
 560
 561     if( tess->callBegin != &noBegin || tess->callEnd != &noEnd
 562        || tess->callVertex != &noVertex || tess->callEdgeFlag != &noEdgeFlag
 563        || tess->callBeginData != &__gl_noBeginData
 564        || tess->callEndData != &__gl_noEndData
 565        || tess->callVertexData != &__gl_noVertexData
 566        || tess->callEdgeFlagData != &__gl_noEdgeFlagData )
 567     {
 568       if( tess->boundaryOnly ) {
 569         __gl_renderBoundary( tess, mesh );  /* output boundary contours */
 570       } else {
 571         __gl_renderMesh( tess, mesh );     /* output strips and fans */
 572       }
 573     }
 574     if( tess->callMesh != &noMesh ) {
 575
 576       /* Throw away the exterior faces, so that all faces are interior.
 577        * This way the user doesn't have to check the "inside" flag,
 578        * and we don't need to even reveal its existence.  It also leaves
 579        * the freedom for an implementation to not generate the exterior
 580        * faces in the first place.
 581        */
 582       __gl_meshDiscardExterior( mesh );
 583       (*tess->callMesh)( mesh );                /* user wants the mesh itself */
 584       tess->mesh = NULL;
 585       tess->polygonData= NULL;
 586       return;
 587     }
 588   }
 589   __gl_meshDeleteMesh( mesh );
 590   tess->polygonData= NULL;
 591   tess->mesh = NULL;
 592 }
 593
 594
 595 /*XXXblythe unused function*/
 596 #if 0
 597 void GLAPIENTRY
 598 gluDeleteMesh( GLUmesh *mesh )
 599 {
 600   __gl_meshDeleteMesh( mesh );
 601 }
 602 #endif
 603
 604
 605
 606 /*******************************************************/
 607
 608 /* Obsolete calls -- for backward compatibility */
 609
 610 void GLAPIENTRY
 611 gluBeginPolygon( GLUtesselator *tess )
 612 {
 613   gluTessBeginPolygon( tess, NULL );
 614   gluTessBeginContour( tess );
 615 }
 616
 617
 618 /*ARGSUSED*/
 619 void GLAPIENTRY
 620 gluNextContour( GLUtesselator *tess, GLenum type )
 621 {
 622   gluTessEndContour( tess );
 623   gluTessBeginContour( tess );
 624 }
 625
 626
 627 void GLAPIENTRY
 628 gluEndPolygon( GLUtesselator *tess )
 629 {
 630   gluTessEndContour( tess );
 631   gluTessEndPolygon( tess );
 632 }