tess.h

Go to the documentation of this file.

/*
 * 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 "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