text: /*
   * 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.
  **
  */
  
  #ifndef __tess_h_
  #define __tess_h_
  
  #include <setjmp.h>
  #include "mesh.h"
  #include "dict.h"
  #include "priorityq.h"
  
  /* The begin/end calls must be properly nested.  We keep track of
   * the current state to enforce the ordering.
   */
  enum TessState { T_DORMANT, T_IN_POLYGON, T_IN_CONTOUR };
  
  /* We cache vertex data for single-contour polygons so that we can
   * try a quick-and-dirty decomposition first.
   */
  #define TESS_MAX_CACHE	100
  
  typedef struct CachedVertex {
    GLdouble	coords[3];
    void		*data;
  } CachedVertex;
  
  struct GLUtesselator {
  
    /*** state needed for collecting the input data ***/
  
    enum TessState state;		/* what begin/end calls have we seen? */
  
    GLUhalfEdge	*lastEdge;	/* lastEdge->Org is the most recent vertex */
    GLUmesh	*mesh;		/* stores the input contours, and eventually
                                     the tessellation itself */
  
    void		(GLAPIENTRY *callError)( GLenum errnum );
  
    /*** state needed for projecting onto the sweep plane ***/
  
    GLdouble	normal[3];	/* user-specified normal (if provided) */
    GLdouble	sUnit[3];	/* unit vector in s-direction (debugging) */
    GLdouble	tUnit[3];	/* unit vector in t-direction (debugging) */
  
    /*** state needed for the line sweep ***/
  
    GLdouble	relTolerance;	/* tolerance for merging features */
    GLenum	windingRule;	/* rule for determining polygon interior */
    GLboolean	fatalError;	/* fatal error: needed combine callback */
  
    Dict		*dict;		/* edge dictionary for sweep line */
    PriorityQ	*pq;		/* priority queue of vertex events */
    GLUvertex	*event;		/* current sweep event being processed */
  
    void		(GLAPIENTRY *callCombine)( GLdouble coords[3], void *data[4],
  			        GLfloat weight[4], void **outData );
  
    /*** state needed for rendering callbacks (see render.c) ***/
  
    GLboolean	flagBoundary;	/* mark boundary edges (use EdgeFlag) */
    GLboolean	boundaryOnly;	/* Extract contours, not triangles */
    GLUface	*lonelyTriList;
      /* list of triangles which could not be rendered as strips or fans */
  
    void		(GLAPIENTRY *callBegin)( GLenum type );
    void		(GLAPIENTRY *callEdgeFlag)( GLboolean boundaryEdge );
    void		(GLAPIENTRY *callVertex)( void *data );
    void		(GLAPIENTRY *callEnd)( void );
    void		(GLAPIENTRY *callMesh)( GLUmesh *mesh );
  
  
    /*** state needed to cache single-contour polygons for renderCache() */
  
    GLboolean	emptyCache;		/* empty cache on next vertex() call */
    int		cacheCount;		/* number of cached vertices */
    CachedVertex	cache[TESS_MAX_CACHE];	/* the vertex data */
  
    /*** rendering callbacks that also pass polygon data  ***/ 
    void		(GLAPIENTRY *callBeginData)( GLenum type, void *polygonData );
    void		(GLAPIENTRY *callEdgeFlagData)( GLboolean boundaryEdge, 
  				     void *polygonData );
    void		(GLAPIENTRY *callVertexData)( void *data, void *polygonData );
    void		(GLAPIENTRY *callEndData)( void *polygonData );
    void		(GLAPIENTRY *callErrorData)( GLenum errnum, void *polygonData );
    void		(GLAPIENTRY *callCombineData)( GLdouble coords[3], void *data[4],
  				    GLfloat weight[4], void **outData,
  				    void *polygonData );
  
    jmp_buf env;			/* place to jump to when memAllocs fail */
  
    void *polygonData;		/* client data for current polygon */
  };
  
  void GLAPIENTRY __gl_noBeginData( GLenum type, void *polygonData );
  void GLAPIENTRY __gl_noEdgeFlagData( GLboolean boundaryEdge, void *polygonData );
  void GLAPIENTRY __gl_noVertexData( void *data, void *polygonData );
  void GLAPIENTRY __gl_noEndData( void *polygonData );
  void GLAPIENTRY __gl_noErrorData( GLenum errnum, void *polygonData );
  void GLAPIENTRY __gl_noCombineData( GLdouble coords[3], void *data[4],
  			 GLfloat weight[4], void **outData,
  			 void *polygonData );
  
  #define CALL_BEGIN_OR_BEGIN_DATA(a) \
     if (tess->callBeginData != &__gl_noBeginData) \
        (*tess->callBeginData)((a),tess->polygonData); \
     else (*tess->callBegin)((a));
  
  #define CALL_VERTEX_OR_VERTEX_DATA(a) \
     if (tess->callVertexData != &__gl_noVertexData) \
        (*tess->callVertexData)((a),tess->polygonData); \
     else (*tess->callVertex)((a));
  
  #define CALL_EDGE_FLAG_OR_EDGE_FLAG_DATA(a) \
     if (tess->callEdgeFlagData != &__gl_noEdgeFlagData) \
        (*tess->callEdgeFlagData)((a),tess->polygonData); \
     else (*tess->callEdgeFlag)((a));
  
  #define CALL_END_OR_END_DATA() \
     if (tess->callEndData != &__gl_noEndData) \
        (*tess->callEndData)(tess->polygonData); \
     else (*tess->callEnd)();
  
  #define CALL_COMBINE_OR_COMBINE_DATA(a,b,c,d) \
     if (tess->callCombineData != &__gl_noCombineData) \
        (*tess->callCombineData)((a),(b),(c),(d),tess->polygonData); \
     else (*tess->callCombine)((a),(b),(c),(d));
  
  #define CALL_ERROR_OR_ERROR_DATA(a) \
     if (tess->callErrorData != &__gl_noErrorData) \
        (*tess->callErrorData)((a),tess->polygonData); \
     else (*tess->callError)((a));
  
  #endif
  