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triangle.h
1 /*****************************************************************************/
2 /* */
3 /* (triangle.h) */
4 /* */
5 /* Include file for programs that call Triangle. */
6 /* */
7 /* Accompanies Triangle Version 1.6 */
8 /* July 28, 2005 */
9 /* */
10 /* Copyright 1996, 2005 */
11 /* Jonathan Richard Shewchuk */
12 /* 2360 Woolsey #H */
13 /* Berkeley, California 94705-1927 */
14 /* jrs@cs.berkeley.edu */
15 /* */
16 /* Modified by Andreas Geiger, 2011 */
17 /*****************************************************************************/
18 
19 /*****************************************************************************/
20 /* */
21 /* How to call Triangle from another program */
22 /* */
23 /* */
24 /* If you haven't read Triangle's instructions (run "triangle -h" to read */
25 /* them), you won't understand what follows. */
26 /* */
27 /* Triangle must be compiled into an object file (triangle.o) with the */
28 /* TRILIBRARY symbol defined (generally by using the -DTRILIBRARY compiler */
29 /* switch). The makefile included with Triangle will do this for you if */
30 /* you run "make trilibrary". The resulting object file can be called via */
31 /* the procedure triangulate(). */
32 /* */
33 /* If the size of the object file is important to you, you may wish to */
34 /* generate a reduced version of triangle.o. The REDUCED symbol gets rid */
35 /* of all features that are primarily of research interest. Specifically, */
36 /* the -DREDUCED switch eliminates Triangle's -i, -F, -s, and -C switches. */
37 /* The CDT_ONLY symbol gets rid of all meshing algorithms above and beyond */
38 /* constrained Delaunay triangulation. Specifically, the -DCDT_ONLY switch */
39 /* eliminates Triangle's -r, -q, -a, -u, -D, -Y, -S, and -s switches. */
40 /* */
41 /* IMPORTANT: These definitions (TRILIBRARY, REDUCED, CDT_ONLY) must be */
42 /* made in the makefile or in triangle.c itself. Putting these definitions */
43 /* in this file (triangle.h) will not create the desired effect. */
44 /* */
45 /* */
46 /* The calling convention for triangulate() follows. */
47 /* */
48 /* void triangulate(triswitches, in, out, vorout) */
49 /* char *triswitches; */
50 /* struct triangulateio *in; */
51 /* struct triangulateio *out; */
52 /* struct triangulateio *vorout; */
53 /* */
54 /* `triswitches' is a string containing the command line switches you wish */
55 /* to invoke. No initial dash is required. Some suggestions: */
56 /* */
57 /* - You'll probably find it convenient to use the `z' switch so that */
58 /* points (and other items) are numbered from zero. This simplifies */
59 /* indexing, because the first item of any type always starts at index */
60 /* [0] of the corresponding array, whether that item's number is zero or */
61 /* one. */
62 /* - You'll probably want to use the `Q' (quiet) switch in your final code, */
63 /* but you can take advantage of Triangle's printed output (including the */
64 /* `V' switch) while debugging. */
65 /* - If you are not using the `q', `a', `u', `D', `j', or `s' switches, */
66 /* then the output points will be identical to the input points, except */
67 /* possibly for the boundary markers. If you don't need the boundary */
68 /* markers, you should use the `N' (no nodes output) switch to save */
69 /* memory. (If you do need boundary markers, but need to save memory, a */
70 /* good nasty trick is to set out->pointlist equal to in->pointlist */
71 /* before calling triangulate(), so that Triangle overwrites the input */
72 /* points with identical copies.) */
73 /* - The `I' (no iteration numbers) and `g' (.off file output) switches */
74 /* have no effect when Triangle is compiled with TRILIBRARY defined. */
75 /* */
76 /* `in', `out', and `vorout' are descriptions of the input, the output, */
77 /* and the Voronoi output. If the `v' (Voronoi output) switch is not used, */
78 /* `vorout' may be NULL. `in' and `out' may never be NULL. */
79 /* */
80 /* Certain fields of the input and output structures must be initialized, */
81 /* as described below. */
82 /* */
83 /*****************************************************************************/
84 
85 /*****************************************************************************/
86 /* */
87 /* The `triangulateio' structure. */
88 /* */
89 /* Used to pass data into and out of the triangulate() procedure. */
90 /* */
91 /* */
92 /* Arrays are used to store points, triangles, markers, and so forth. In */
93 /* all cases, the first item in any array is stored starting at index [0]. */
94 /* However, that item is item number `1' unless the `z' switch is used, in */
95 /* which case it is item number `0'. Hence, you may find it easier to */
96 /* index points (and triangles in the neighbor list) if you use the `z' */
97 /* switch. Unless, of course, you're calling Triangle from a Fortran */
98 /* program. */
99 /* */
100 /* Description of fields (except the `numberof' fields, which are obvious): */
101 /* */
102 /* `pointlist': An array of point coordinates. The first point's x */
103 /* coordinate is at index [0] and its y coordinate at index [1], followed */
104 /* by the coordinates of the remaining points. Each point occupies two */
105 /* REALs. */
106 /* `pointattributelist': An array of point attributes. Each point's */
107 /* attributes occupy `numberofpointattributes' REALs. */
108 /* `pointmarkerlist': An array of point markers; one int per point. */
109 /* */
110 /* `trianglelist': An array of triangle corners. The first triangle's */
111 /* first corner is at index [0], followed by its other two corners in */
112 /* counterclockwise order, followed by any other nodes if the triangle */
113 /* represents a nonlinear element. Each triangle occupies */
114 /* `numberofcorners' ints. */
115 /* `triangleattributelist': An array of triangle attributes. Each */
116 /* triangle's attributes occupy `numberoftriangleattributes' REALs. */
117 /* `trianglearealist': An array of triangle area constraints; one REAL per */
118 /* triangle. Input only. */
119 /* `neighborlist': An array of triangle neighbors; three ints per */
120 /* triangle. Output only. */
121 /* */
122 /* `segmentlist': An array of segment endpoints. The first segment's */
123 /* endpoints are at indices [0] and [1], followed by the remaining */
124 /* segments. Two ints per segment. */
125 /* `segmentmarkerlist': An array of segment markers; one int per segment. */
126 /* */
127 /* `holelist': An array of holes. The first hole's x and y coordinates */
128 /* are at indices [0] and [1], followed by the remaining holes. Two */
129 /* REALs per hole. Input only, although the pointer is copied to the */
130 /* output structure for your convenience. */
131 /* */
132 /* `regionlist': An array of regional attributes and area constraints. */
133 /* The first constraint's x and y coordinates are at indices [0] and [1], */
134 /* followed by the regional attribute at index [2], followed by the */
135 /* maximum area at index [3], followed by the remaining area constraints. */
136 /* Four REALs per area constraint. Note that each regional attribute is */
137 /* used only if you select the `A' switch, and each area constraint is */
138 /* used only if you select the `a' switch (with no number following), but */
139 /* omitting one of these switches does not change the memory layout. */
140 /* Input only, although the pointer is copied to the output structure for */
141 /* your convenience. */
142 /* */
143 /* `edgelist': An array of edge endpoints. The first edge's endpoints are */
144 /* at indices [0] and [1], followed by the remaining edges. Two ints per */
145 /* edge. Output only. */
146 /* `edgemarkerlist': An array of edge markers; one int per edge. Output */
147 /* only. */
148 /* `normlist': An array of normal vectors, used for infinite rays in */
149 /* Voronoi diagrams. The first normal vector's x and y magnitudes are */
150 /* at indices [0] and [1], followed by the remaining vectors. For each */
151 /* finite edge in a Voronoi diagram, the normal vector written is the */
152 /* zero vector. Two REALs per edge. Output only. */
153 /* */
154 /* */
155 /* Any input fields that Triangle will examine must be initialized. */
156 /* Furthermore, for each output array that Triangle will write to, you */
157 /* must either provide space by setting the appropriate pointer to point */
158 /* to the space you want the data written to, or you must initialize the */
159 /* pointer to NULL, which tells Triangle to allocate space for the results. */
160 /* The latter option is preferable, because Triangle always knows exactly */
161 /* how much space to allocate. The former option is provided mainly for */
162 /* people who need to call Triangle from Fortran code, though it also makes */
163 /* possible some nasty space-saving tricks, like writing the output to the */
164 /* same arrays as the input. */
165 /* */
166 /* Triangle will not free() any input or output arrays, including those it */
167 /* allocates itself; that's up to you. You should free arrays allocated by */
168 /* Triangle by calling the trifree() procedure defined below. (By default, */
169 /* trifree() just calls the standard free() library procedure, but */
170 /* applications that call triangulate() may replace trimalloc() and */
171 /* trifree() in triangle.c to use specialized memory allocators.) */
172 /* */
173 /* Here's a guide to help you decide which fields you must initialize */
174 /* before you call triangulate(). */
175 /* */
176 /* `in': */
177 /* */
178 /* - `pointlist' must always point to a list of points; `numberofpoints' */
179 /* and `numberofpointattributes' must be properly set. */
180 /* `pointmarkerlist' must either be set to NULL (in which case all */
181 /* markers default to zero), or must point to a list of markers. If */
182 /* `numberofpointattributes' is not zero, `pointattributelist' must */
183 /* point to a list of point attributes. */
184 /* - If the `r' switch is used, `trianglelist' must point to a list of */
185 /* triangles, and `numberoftriangles', `numberofcorners', and */
186 /* `numberoftriangleattributes' must be properly set. If */
187 /* `numberoftriangleattributes' is not zero, `triangleattributelist' */
188 /* must point to a list of triangle attributes. If the `a' switch is */
189 /* used (with no number following), `trianglearealist' must point to a */
190 /* list of triangle area constraints. `neighborlist' may be ignored. */
191 /* - If the `p' switch is used, `segmentlist' must point to a list of */
192 /* segments, `numberofsegments' must be properly set, and */
193 /* `segmentmarkerlist' must either be set to NULL (in which case all */
194 /* markers default to zero), or must point to a list of markers. */
195 /* - If the `p' switch is used without the `r' switch, then */
196 /* `numberofholes' and `numberofregions' must be properly set. If */
197 /* `numberofholes' is not zero, `holelist' must point to a list of */
198 /* holes. If `numberofregions' is not zero, `regionlist' must point to */
199 /* a list of region constraints. */
200 /* - If the `p' switch is used, `holelist', `numberofholes', */
201 /* `regionlist', and `numberofregions' is copied to `out'. (You can */
202 /* nonetheless get away with not initializing them if the `r' switch is */
203 /* used.) */
204 /* - `edgelist', `edgemarkerlist', `normlist', and `numberofedges' may be */
205 /* ignored. */
206 /* */
207 /* `out': */
208 /* */
209 /* - `pointlist' must be initialized (NULL or pointing to memory) unless */
210 /* the `N' switch is used. `pointmarkerlist' must be initialized */
211 /* unless the `N' or `B' switch is used. If `N' is not used and */
212 /* `in->numberofpointattributes' is not zero, `pointattributelist' must */
213 /* be initialized. */
214 /* - `trianglelist' must be initialized unless the `E' switch is used. */
215 /* `neighborlist' must be initialized if the `n' switch is used. If */
216 /* the `E' switch is not used and (`in->numberofelementattributes' is */
217 /* not zero or the `A' switch is used), `elementattributelist' must be */
218 /* initialized. `trianglearealist' may be ignored. */
219 /* - `segmentlist' must be initialized if the `p' or `c' switch is used, */
220 /* and the `P' switch is not used. `segmentmarkerlist' must also be */
221 /* initialized under these circumstances unless the `B' switch is used. */
222 /* - `edgelist' must be initialized if the `e' switch is used. */
223 /* `edgemarkerlist' must be initialized if the `e' switch is used and */
224 /* the `B' switch is not. */
225 /* - `holelist', `regionlist', `normlist', and all scalars may be ignored.*/
226 /* */
227 /* `vorout' (only needed if `v' switch is used): */
228 /* */
229 /* - `pointlist' must be initialized. If `in->numberofpointattributes' */
230 /* is not zero, `pointattributelist' must be initialized. */
231 /* `pointmarkerlist' may be ignored. */
232 /* - `edgelist' and `normlist' must both be initialized. */
233 /* `edgemarkerlist' may be ignored. */
234 /* - Everything else may be ignored. */
235 /* */
236 /* After a call to triangulate(), the valid fields of `out' and `vorout' */
237 /* will depend, in an obvious way, on the choice of switches used. Note */
238 /* that when the `p' switch is used, the pointers `holelist' and */
239 /* `regionlist' are copied from `in' to `out', but no new space is */
240 /* allocated; be careful that you don't free() the same array twice. On */
241 /* the other hand, Triangle will never copy the `pointlist' pointer (or any */
242 /* others); new space is allocated for `out->pointlist', or if the `N' */
243 /* switch is used, `out->pointlist' remains uninitialized. */
244 /* */
245 /* All of the meaningful `numberof' fields will be properly set; for */
246 /* instance, `numberofedges' will represent the number of edges in the */
247 /* triangulation whether or not the edges were written. If segments are */
248 /* not used, `numberofsegments' will indicate the number of boundary edges. */
249 /* */
250 /*****************************************************************************/
251 
252 struct triangulateio {
253  float *pointlist; /* In / out */
254  float *pointattributelist; /* In / out */
255  int *pointmarkerlist; /* In / out */
256  int numberofpoints; /* In / out */
257  int numberofpointattributes; /* In / out */
258 
259  int *trianglelist; /* In / out */
260  float *triangleattributelist; /* In / out */
261  float *trianglearealist; /* In only */
262  int *neighborlist; /* Out only */
263  int numberoftriangles; /* In / out */
264  int numberofcorners; /* In / out */
265  int numberoftriangleattributes; /* In / out */
266 
267  int *segmentlist; /* In / out */
268  int *segmentmarkerlist; /* In / out */
269  int numberofsegments; /* In / out */
270 
271  float *holelist; /* In / pointer to array copied out */
272  int numberofholes; /* In / copied out */
273 
274  float *regionlist; /* In / pointer to array copied out */
275  int numberofregions; /* In / copied out */
276 
277  int *edgelist; /* Out only */
278  int *edgemarkerlist; /* Not used with Voronoi diagram; out only */
279  float *normlist; /* Used only with Voronoi diagram; out only */
280  int numberofedges; /* Out only */
281 };
282 
283 void triangulate(char *,triangulateio *,triangulateio *,triangulateio *);
284 void trifree(int *memptr);
285 
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