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tess.h
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30 /*
31 ** Author: Eric Veach, July 1994.
32 **
33 */
34 
35 #ifndef __tess_h_
36 #define __tess_h_
37 
38 #include "GL_glu.h"
39 #include <setjmp.h>
40 #include "mesh.h"
41 #include "dict.h"
42 #include "priorityq.h"
43 
44 /* The begin/end calls must be properly nested. We keep track of
45  * the current state to enforce the ordering.
46  */
47 enum TessState { T_DORMANT, T_IN_POLYGON, T_IN_CONTOUR };
48 
49 /* We cache vertex data for single-contour polygons so that we can
50  * try a quick-and-dirty decomposition first.
51  */
52 #define TESS_MAX_CACHE 100
53 
54 typedef struct CachedVertex {
55  GLdouble coords[3];
56  void *data;
57 } CachedVertex;
58 
59 struct GLUtesselator {
60 
61  /*** state needed for collecting the input data ***/
62 
63  enum TessState state; /* what begin/end calls have we seen? */
64 
65  GLUhalfEdge *lastEdge; /* lastEdge->Org is the most recent vertex */
66  GLUmesh *mesh; /* stores the input contours, and eventually
67  the tessellation itself */
68 
69  void (GLAPIENTRY *callError)( GLenum errnum );
70 
71  /*** state needed for projecting onto the sweep plane ***/
72 
73  GLdouble normal[3]; /* user-specified normal (if provided) */
74  GLdouble sUnit[3]; /* unit vector in s-direction (debugging) */
75  GLdouble tUnit[3]; /* unit vector in t-direction (debugging) */
76 
77  /*** state needed for the line sweep ***/
78 
79  GLdouble relTolerance; /* tolerance for merging features */
80  GLenum windingRule; /* rule for determining polygon interior */
81  GLboolean fatalError; /* fatal error: needed combine callback */
82 
83  Dict *dict; /* edge dictionary for sweep line */
84  PriorityQ *pq; /* priority queue of vertex events */
85  GLUvertex *event; /* current sweep event being processed */
86 
87  void (GLAPIENTRY *callCombine)( GLdouble coords[3], void *data[4],
88  GLfloat weight[4], void **outData );
89 
90  /*** state needed for rendering callbacks (see render.c) ***/
91 
92  GLboolean flagBoundary; /* mark boundary edges (use EdgeFlag) */
93  GLboolean boundaryOnly; /* Extract contours, not triangles */
94  GLUface *lonelyTriList;
95  /* list of triangles which could not be rendered as strips or fans */
96 
97  void (GLAPIENTRY *callBegin)( GLenum type );
98  void (GLAPIENTRY *callEdgeFlag)( GLboolean boundaryEdge );
99  void (GLAPIENTRY *callVertex)( void *data );
100  void (GLAPIENTRY *callEnd)( void );
101  void (GLAPIENTRY *callMesh)( GLUmesh *mesh );
102 
103 
104  /*** state needed to cache single-contour polygons for renderCache() */
105 
106  GLboolean emptyCache; /* empty cache on next vertex() call */
107  int cacheCount; /* number of cached vertices */
108  CachedVertex cache[TESS_MAX_CACHE]; /* the vertex data */
109 
110  /*** rendering callbacks that also pass polygon data ***/
111  void (GLAPIENTRY *callBeginData)( GLenum type, void *polygonData );
112  void (GLAPIENTRY *callEdgeFlagData)( GLboolean boundaryEdge,
113  void *polygonData );
114  void (GLAPIENTRY *callVertexData)( void *data, void *polygonData );
115  void (GLAPIENTRY *callEndData)( void *polygonData );
116  void (GLAPIENTRY *callErrorData)( GLenum errnum, void *polygonData );
117  void (GLAPIENTRY *callCombineData)( GLdouble coords[3], void *data[4],
118  GLfloat weight[4], void **outData,
119  void *polygonData );
120 
121  jmp_buf env; /* place to jump to when memAllocs fail */
122 
123  void *polygonData; /* client data for current polygon */
124 };
125 
126 void GLAPIENTRY __gl_noBeginData( GLenum type, void *polygonData );
127 void GLAPIENTRY __gl_noEdgeFlagData( GLboolean boundaryEdge, void *polygonData );
128 void GLAPIENTRY __gl_noVertexData( void *data, void *polygonData );
129 void GLAPIENTRY __gl_noEndData( void *polygonData );
130 void GLAPIENTRY __gl_noErrorData( GLenum errnum, void *polygonData );
131 void GLAPIENTRY __gl_noCombineData( GLdouble coords[3], void *data[4],
132  GLfloat weight[4], void **outData,
133  void *polygonData );
134 
135 #define CALL_BEGIN_OR_BEGIN_DATA(a) \
136  if (tess->callBeginData != &__gl_noBeginData) \
137  (*tess->callBeginData)((a),tess->polygonData); \
138  else (*tess->callBegin)((a));
139 
140 #define CALL_VERTEX_OR_VERTEX_DATA(a) \
141  if (tess->callVertexData != &__gl_noVertexData) \
142  (*tess->callVertexData)((a),tess->polygonData); \
143  else (*tess->callVertex)((a));
144 
145 #define CALL_EDGE_FLAG_OR_EDGE_FLAG_DATA(a) \
146  if (tess->callEdgeFlagData != &__gl_noEdgeFlagData) \
147  (*tess->callEdgeFlagData)((a),tess->polygonData); \
148  else (*tess->callEdgeFlag)((a));
149 
150 #define CALL_END_OR_END_DATA() \
151  if (tess->callEndData != &__gl_noEndData) \
152  (*tess->callEndData)(tess->polygonData); \
153  else (*tess->callEnd)();
154 
155 #define CALL_COMBINE_OR_COMBINE_DATA(a,b,c,d) \
156  if (tess->callCombineData != &__gl_noCombineData) \
157  (*tess->callCombineData)((a),(b),(c),(d),tess->polygonData); \
158  else (*tess->callCombine)((a),(b),(c),(d));
159 
160 #define CALL_ERROR_OR_ERROR_DATA(a) \
161  if (tess->callErrorData != &__gl_noErrorData) \
162  (*tess->callErrorData)((a),tess->polygonData); \
163  else (*tess->callError)((a));
164 
165 #endif
GL_glu.h