summaryrefslogtreecommitdiff
path: root/src/glu/sgi/libnurbs/internals/monoTriangulationBackend.cc
blob: 111b8bea48881687061012968a77d205076dc82e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
/*
** License Applicability. Except to the extent portions of this file are
** made subject to an alternative license as permitted in the SGI Free
** Software License B, Version 1.1 (the "License"), the contents of this
** file are subject only to the provisions of the License. You may not use
** this file except in compliance with the License. You may obtain a copy
** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
** 
** http://oss.sgi.com/projects/FreeB
** 
** Note that, as provided in the License, the Software is distributed on an
** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
** 
** Original Code. The Original Code is: OpenGL Sample Implementation,
** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
** Copyright in any portions created by third parties is as indicated
** elsewhere herein. All Rights Reserved.
** 
** Additional Notice Provisions: The application programming interfaces
** established by SGI in conjunction with the Original Code are The
** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
** Window System(R) (Version 1.3), released October 19, 1998. This software
** was created using the OpenGL(R) version 1.2.1 Sample Implementation
** published by SGI, but has not been independently verified as being
** compliant with the OpenGL(R) version 1.2.1 Specification.
**
** $Date: 2004/05/12 15:29:36 $ $Revision: 1.2 $
*/
/*
** $Header: /home/krh/git/sync/mesa-cvs-repo/Mesa/src/glu/sgi/libnurbs/internals/monoTriangulationBackend.cc,v 1.2 2004/05/12 15:29:36 brianp Exp $
*/

#include "monoTriangulation.h"
#include "polyUtil.h"
#include "backend.h"
#include "arc.h"

void reflexChain::outputFan(Real v[2], Backend* backend)
{
  Int i;
  /*
  TrimVertex trimVert;
  */
  backend->bgntfan();

  /*
  trimVert.param[0]=v[0];
  trimVert.param[1]=v[1];
  backend->tmeshvert(&trimVert);
  */
  backend->tmeshvert(v[0], v[1]);

  if(isIncreasing) {
    for(i=0; i<index_queue; i++)
      {
	/*
	trimVert.param[0]=queue[i][0];
	trimVert.param[1]=queue[i][1];
	backend->tmeshvert(&trimVert);
	*/
	backend->tmeshvert(queue[i][0], queue[i][1]);
      }
  }
  else {
    for(i=index_queue-1; i>=0; i--)
      {
	/*
	trimVert.param[0]=queue[i][0];
	trimVert.param[1]=queue[i][1];
	backend->tmeshvert(&trimVert);
	*/
	backend->tmeshvert(queue[i][0], queue[i][1]);
      }
  }
  backend->endtfan();
}

void reflexChain::processNewVertex(Real v[2], Backend* backend)
{
  Int i,j,k;
  Int isReflex;
  TrimVertex trimVert;
  /*if there are at most one vertex in the queue, then simply insert
   */
  if(index_queue <=1){
    insert(v);
    return;
  }
  
  /*there are at least two vertices in the queue*/
  j=index_queue-1;
  
  for(i=j; i>=1; i--) {
    if(isIncreasing) {
      isReflex = (area(queue[i-1], queue[i], v) <= 0.0);
    }
    else /*decreasing*/{
      isReflex = (area(v, queue[i], queue[i-1]) <= 0.0);	  
    }
    if(isReflex) {
      break;
    }
  }

  /*
   *if i<j then vertices: i+1--j are convex
   * output triangle fan: 
   *  v, and queue[i], i+1, ..., j
   */
  if(i<j) 
    {
      backend->bgntfan();
      /*
      trimVert.param[0]=v[0];
      trimVert.param[1]=v[1];
      backend->tmeshvert(& trimVert);
      */
      backend->tmeshvert(v[0], v[1]);

      if(isIncreasing) {
	for(k=i; k<=j; k++)
	  {
	    /*
	    trimVert.param[0]=queue[k][0];
	    trimVert.param[1]=queue[k][1];
	    backend->tmeshvert(& trimVert);
	    */
	    backend->tmeshvert(queue[k][0], queue[k][1]);
	  }
      }
      else {
	for(k=j; k>=i; k--)
	  {
	    /*
	    trimVert.param[0]=queue[k][0];
	    trimVert.param[1]=queue[k][1];
	    backend->tmeshvert(& trimVert);
	    */
	    backend->tmeshvert(queue[k][0], queue[k][1]);
	  }
      }
      
      backend->endtfan();
    }

  /*delete vertices i+1--j from the queue*/
  index_queue = i+1;
  /*finally insert v at the end of the queue*/
  insert(v);

}


void monoTriangulationRec(Real* topVertex, Real* botVertex, 
			  vertexArray* inc_chain, Int inc_current,
			  vertexArray* dec_chain, Int dec_current,
			  Backend* backend)
{
  assert( inc_chain != NULL && dec_chain != NULL);
  assert( ! (inc_current>=inc_chain->getNumElements() &&
	     dec_current>=dec_chain->getNumElements()));
  Int inc_nVertices;
  Int dec_nVertices;
  Real** inc_array ;
  Real** dec_array ;
  Int i;
  assert( ! ( (inc_chain==NULL) && (dec_chain==NULL)));

  if(inc_current>=inc_chain->getNumElements()) /*no more vertices on inc_chain*/
    {

      dec_array = dec_chain->getArray();
      dec_nVertices = dec_chain->getNumElements();      
      reflexChain rChain(20,0);
      /*put the top vertex into the reflex chain*/
      rChain.processNewVertex(topVertex, backend);
      /*process all the vertices on the dec_chain*/
      for(i=dec_current; i<dec_nVertices; i++){
	rChain.processNewVertex(dec_array[i], backend);
      }
      /*process the bottom vertex*/
      rChain.processNewVertex(botVertex, backend);

    }
  else if(dec_current>= dec_chain->getNumElements()) /*no more vertices on dec_chain*/
    {
      inc_array = inc_chain->getArray();
      inc_nVertices= inc_chain->getNumElements();
      reflexChain rChain(20,1);
      /*put the top vertex into the reflex chain*/
      rChain.processNewVertex(topVertex, backend);
      /*process all the vertices on the inc_chain*/
      for(i=inc_current; i<inc_nVertices; i++){
	rChain.processNewVertex(inc_array[i], backend);
      }
      /*process the bottom vertex*/
      rChain.processNewVertex(botVertex, backend);
    }
  else /*neither chain is empty*/
    {
      inc_array = inc_chain -> getArray();
      dec_array = dec_chain -> getArray();
      inc_nVertices= inc_chain->getNumElements();
      dec_nVertices= dec_chain->getNumElements();
      /*if top of inc_chain is 'lower' than top of dec_chain, process all the 
       *vertices on the dec_chain which are higher than top of inc_chain
       */
      if(compV2InY(inc_array[inc_current], dec_array[dec_current]) <= 0)
	{

	  reflexChain rChain(20, 0);
	  rChain.processNewVertex(topVertex, backend);
	  for(i=dec_current; i<dec_nVertices; i++)
	    {
	      if(compV2InY(inc_array[inc_current], dec_array[i]) <= 0)
		rChain.processNewVertex(dec_array[i], backend);
	      else 
		break;
	    }
	  rChain.outputFan(inc_array[inc_current], backend);
	  monoTriangulationRec(dec_array[i-1], botVertex, 
			       inc_chain, inc_current,
			       dec_chain, i,
			       backend);
	}
      else /*compV2InY(inc_array[inc_current], dec_array[dec_current]) > 0*/
	{

	  reflexChain rChain(20, 1);
	  rChain.processNewVertex(topVertex, backend);
	  for(i=inc_current; i<inc_nVertices; i++)
	    {
	      if(compV2InY(inc_array[i], dec_array[dec_current]) >0)		
		rChain.processNewVertex(inc_array[i], backend);	      
	      else
		break;
	    }
	  rChain.outputFan(dec_array[dec_current], backend);
	  monoTriangulationRec(inc_array[i-1], botVertex, 
			       inc_chain, i,
			       dec_chain, dec_current,
			       backend);
	}
    }/*end case neither is empty*/
}


void monoTriangulationFunBackend(Arc_ptr loop, Int (*compFun)(Real*, Real*), Backend* backend)
{
  Int i;
  /*find the top vertex, bottom vertex, inccreasing chain, and decreasing chain,
   *then call monoTriangulationRec
   */
  Arc_ptr tempV;
  Arc_ptr topV;
  Arc_ptr botV;
  topV = botV = loop;
  for(tempV = loop->next; tempV != loop; tempV = tempV->next)
    {
      if(compFun(topV->tail(), tempV->tail())<0) {
	topV = tempV;
      }
      if(compFun(botV->tail(), tempV->tail())>0) {
	botV = tempV;
      }
    }

  /*creat increase and decrease chains*/
  vertexArray inc_chain(20); /*this is a dynamic array*/
  for(i=1; i<=topV->pwlArc->npts-2; i++) { /*the first vertex is the top vertex which doesn't belong to inc_chain*/
    inc_chain.appendVertex(topV->pwlArc->pts[i].param);
  }
  for(tempV = topV->next; tempV != botV; tempV = tempV->next)
    {
      for(i=0; i<=tempV->pwlArc->npts-2; i++){
	inc_chain.appendVertex(tempV->pwlArc->pts[i].param);
      }
    }
  
  vertexArray dec_chain(20);
  for(tempV = topV->prev; tempV != botV; tempV = tempV->prev)
    {
      for(i=tempV->pwlArc->npts-2; i>=0; i--){
	dec_chain.appendVertex(tempV->pwlArc->pts[i].param);
      }
    }
  for(i=botV->pwlArc->npts-2; i>=1; i--){ 
    dec_chain.appendVertex(tempV->pwlArc->pts[i].param);
  }
  
  monoTriangulationRecFunBackend(topV->tail(), botV->tail(), &inc_chain, 0, &dec_chain, 0, compFun, backend);

}  

/*if compFun == compV2InY, top to bottom: V-monotone
 *if compFun == compV2InX, right to left: U-monotone
 */
void monoTriangulationRecFunBackend(Real* topVertex, Real* botVertex, 
			  vertexArray* inc_chain, Int inc_current,
			  vertexArray* dec_chain, Int dec_current,
			  Int  (*compFun)(Real*, Real*),
			  Backend* backend)
{
  assert( inc_chain != NULL && dec_chain != NULL);
  assert( ! (inc_current>=inc_chain->getNumElements() &&
	     dec_current>=dec_chain->getNumElements()));
  Int inc_nVertices;
  Int dec_nVertices;
  Real** inc_array ;
  Real** dec_array ;
  Int i;
  assert( ! ( (inc_chain==NULL) && (dec_chain==NULL)));

  if(inc_current>=inc_chain->getNumElements()) /*no more vertices on inc_chain*/
    {

      dec_array = dec_chain->getArray();
      dec_nVertices = dec_chain->getNumElements();      
      reflexChain rChain(20,0);
      /*put the top vertex into the reflex chain*/
      rChain.processNewVertex(topVertex, backend);
      /*process all the vertices on the dec_chain*/
      for(i=dec_current; i<dec_nVertices; i++){
	rChain.processNewVertex(dec_array[i], backend);
      }
      /*process the bottom vertex*/
      rChain.processNewVertex(botVertex, backend);

    }
  else if(dec_current>= dec_chain->getNumElements()) /*no more vertices on dec_chain*/
    {
      inc_array = inc_chain->getArray();
      inc_nVertices= inc_chain->getNumElements();
      reflexChain rChain(20,1);
      /*put the top vertex into the reflex chain*/
      rChain.processNewVertex(topVertex, backend);
      /*process all the vertices on the inc_chain*/
      for(i=inc_current; i<inc_nVertices; i++){
	rChain.processNewVertex(inc_array[i], backend);
      }
      /*process the bottom vertex*/
      rChain.processNewVertex(botVertex, backend);
    }
  else /*neither chain is empty*/
    {
      inc_array = inc_chain -> getArray();
      dec_array = dec_chain -> getArray();
      inc_nVertices= inc_chain->getNumElements();
      dec_nVertices= dec_chain->getNumElements();
      /*if top of inc_chain is 'lower' than top of dec_chain, process all the 
       *vertices on the dec_chain which are higher than top of inc_chain
       */
      if(compFun(inc_array[inc_current], dec_array[dec_current]) <= 0)
	{

	  reflexChain rChain(20, 0);
	  rChain.processNewVertex(topVertex, backend);
	  for(i=dec_current; i<dec_nVertices; i++)
	    {
	      if(compFun(inc_array[inc_current], dec_array[i]) <= 0)
		rChain.processNewVertex(dec_array[i], backend);
	      else 
		break;
	    }
	  rChain.outputFan(inc_array[inc_current], backend);
	  monoTriangulationRecFunBackend(dec_array[i-1], botVertex, 
			       inc_chain, inc_current,
			       dec_chain, i,
			       compFun,
			       backend);
	}
      else /*compFun(inc_array[inc_current], dec_array[dec_current]) > 0*/
	{

	  reflexChain rChain(20, 1);
	  rChain.processNewVertex(topVertex, backend);
	  for(i=inc_current; i<inc_nVertices; i++)
	    {
	      if(compFun(inc_array[i], dec_array[dec_current]) >0)		
		rChain.processNewVertex(inc_array[i], backend);	      
	      else
		break;
	    }
	  rChain.outputFan(dec_array[dec_current], backend);
	  monoTriangulationRecFunBackend(inc_array[i-1], botVertex, 
			       inc_chain, i,
			       dec_chain, dec_current,
			       compFun,
			       backend);
	}
    }/*end case neither is empty*/
}