tess.h

/*
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 * shall be included in all copies or substantial portions of the Software.
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/*
** Author: Eric Veach, July 1994.
**
*/

#ifndef __tess_h_
#define __tess_h_

#include "glues.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
{
   double coords[3];
   void*   data;
} CachedVertex;

struct GLUEStesselator
{
   /*** state needed for collecting the input data ***/
   enum TessState state;        /* what begin/end calls have we seen? */

   GLUEShalfEdge* lastEdge;       /* lastEdge->Org is the most recent vertex */
   GLUESmesh* mesh;               /* stores the input contours, and eventually
                                   the tessellation itself */

   void (* callError)(GLenum errnum);

   /*** state needed for projecting onto the sweep plane ***/
   double normal[3]; /* user-specified normal (if provided) */
   GLfloat sUnit[3];  /* unit vector in s-direction (debugging) */
   GLfloat tUnit[3];  /* unit vector in t-direction (debugging) */

   /*** state needed for the line sweep ***/
   GLfloat   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 */
   GLUESvertex* event;            /* current sweep event being processed */

   void (* callCombine)(double 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    */
  /* list of triangles which could not be rendered as strips or fans */
  GLUESface*      lonelyTriList;

  void (* callBegin)(GLenum type);
  void (* callEdgeFlag)(GLboolean boundaryEdge);
  void (* callVertex)(void* data);
  void (* callEnd)(void);
  void (* callMesh)(GLUESmesh* 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 (* callBeginData)(GLenum type, void* polygonData);
  void (* callEdgeFlagData)(GLboolean boundaryEdge, void* polygonData);
  void (* callVertexData)(void* data, void* polygonData);
  void (* callEndData)(void* polygonData);
  void (* callErrorData)(GLenum errnum, void *polygonData);
  void (* callCombineData)(double 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  __gl_noBeginData(GLenum type, void* polygonData);
 void  __gl_noEdgeFlagData(GLboolean boundaryEdge, void* polygonData);
 void  __gl_noVertexData(void* data, void* polygonData);
 void  __gl_noEndData(void* polygonData);
 void  __gl_noErrorData(GLenum errnum, void* polygonData);
 void  __gl_noCombineData(double 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 /* __tess_h_ */