tess.h

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/*
** Author: Eric Veach, July 1994.
**
*/

#ifndef __tess_h_
#define __tess_h_

//#include <GL/glu.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