Welcome to mirror list, hosted at ThFree Co, Russian Federation.

BSP_CSGMesh.cpp « intern « bsp « intern - git.blender.org/blender.git - Unnamed repository; edit this file 'description' to name the repository.
summaryrefslogtreecommitdiff
blob: d1721cb692b024690593370521ff84399e848bb6 (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
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
/**
 * $Id$
 * ***** BEGIN GPL/BL DUAL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version. The Blender
 * Foundation also sells licenses for use in proprietary software under
 * the Blender License.  See http://www.blender.org/BL/ for information
 * about this.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL/BL DUAL LICENSE BLOCK *****
 */



#include "BSP_CSGMesh.h"
#include "MT_assert.h"
#include "CTR_TaggedSetOps.h"
#include "BSP_MeshFragment.h"
#include "MT_Plane3.h"
#include "BSP_CSGException.h"

// for vector reverse
#include <algorithm>
using namespace std;

BSP_CSGMesh::
BSP_CSGMesh(
) :
	MEM_RefCountable()
{
    // nothing to do
}

	BSP_CSGMesh *
BSP_CSGMesh::
New(
){
	return new BSP_CSGMesh();
}

	BSP_CSGMesh *
BSP_CSGMesh::
NewCopy(
) const {

	MEM_SmartPtr<BSP_CSGMesh> mesh = New();
	if (mesh == NULL) return NULL;

	mesh->m_bbox_max = m_bbox_max;
	mesh->m_bbox_min = m_bbox_min;

	if (m_edges != NULL) {
		mesh->m_edges = new vector<BSP_MEdge>(m_edges.Ref());
		if (mesh->m_edges == NULL) return NULL;
	}
	if (m_verts != NULL) {
		mesh->m_verts = new vector<BSP_MVertex>(m_verts.Ref());
		if (mesh->m_verts == NULL) return NULL;
	}
	if (m_faces != NULL) {
		mesh->m_faces = new vector<BSP_MFace>(m_faces.Ref());
		if (mesh->m_faces == NULL) return NULL;
	}
	if (m_fv_data != NULL) {
		mesh->m_fv_data = new BSP_CSGUserData(m_fv_data.Ref());
		if (mesh->m_fv_data == NULL) return NULL;
	}
	if (m_face_data != NULL) {
		mesh->m_face_data = new BSP_CSGUserData(m_face_data.Ref());
		if (mesh->m_face_data == NULL) return NULL;
	}

	return mesh.Release();
}
	
	void
BSP_CSGMesh::
Invert(
){

	vector<BSP_MFace> & faces = FaceSet();

	vector<BSP_MFace>::const_iterator faces_end = faces.end();
	vector<BSP_MFace>::iterator faces_it = faces.begin();

	for (; faces_it != faces_end; ++faces_it) {	
		faces_it->Invert();
	}
}

	bool
BSP_CSGMesh::
SetVertices(
	MEM_SmartPtr<vector<BSP_MVertex> > verts
){
	if (verts == NULL) return false;

	// create polygon and edge arrays and reserve some space.
	m_faces = new vector<BSP_MFace>;
	if (!m_faces) return false;

	m_faces->reserve(verts->size()/2);
	
	// previous verts get deleted here.
	m_verts = verts;
	return true;
}

	void
BSP_CSGMesh::
SetFaceVertexData(
	MEM_SmartPtr<BSP_CSGUserData> fv_data
){
	m_fv_data = fv_data;
}

	void
BSP_CSGMesh::
SetFaceData(
	MEM_SmartPtr<BSP_CSGUserData> f_data
) {
	m_face_data = f_data;
}


		void
BSP_CSGMesh::
AddPolygon(
	const int * verts,
	int num_verts
){
	MT_assert(verts != NULL);
	MT_assert(num_verts >=3);

	if (verts == NULL || num_verts <3) return;

	const int vertex_num = m_verts->size();

	// make a polyscone from these vertex indices.

	const BSP_FaceInd fi = m_faces->size();
	m_faces->push_back(BSP_MFace());			
	BSP_MFace & face = m_faces->back();

	insert_iterator<vector<BSP_VertexInd> > insert_point(face.m_verts,face.m_verts.end()); 
	copy (verts,verts + num_verts,insert_point);

	// compute and store the plane equation for this face.

	MT_Plane3 face_plane = FacePlane(fi);	
	face.m_plane = face_plane;
};

	void
BSP_CSGMesh::
AddPolygon(
	const int * verts,
	const int * fv_indices,
	int num_verts
){
	// This creates a new polygon on the end of the face list.
	AddPolygon(verts,num_verts);

	BSP_MFace & face = m_faces->back();
	// now we just fill in the fv indices

	if (fv_indices) {
		insert_iterator<vector<BSP_UserFVInd> > insert_point(face.m_fv_data,face.m_fv_data.end());
		copy(fv_indices,fv_indices + num_verts,insert_point);
	} else {
		face.m_fv_data.insert(face.m_fv_data.end(),num_verts,BSP_UserFVInd::Empty());
	}
}


	void
BSP_CSGMesh::
AddSubTriangle(
	const BSP_MFace &iface,
	const int * index_info
){
	// This creates a new polygon on the end of the face list.

	const BSP_FaceInd fi = m_faces->size();
	m_faces->push_back(BSP_MFace());			
	BSP_MFace & face = m_faces->back();

	face.m_verts.push_back(iface.m_verts[index_info[0]]);
	face.m_verts.push_back(iface.m_verts[index_info[1]]);
	face.m_verts.push_back(iface.m_verts[index_info[2]]);

	face.m_fv_data.push_back(iface.m_fv_data[index_info[0]]);
	face.m_fv_data.push_back(iface.m_fv_data[index_info[1]]);
	face.m_fv_data.push_back(iface.m_fv_data[index_info[2]]);

	face.m_plane = iface.m_plane;
}

	
// assumes that the face already has a plane equation
	void
BSP_CSGMesh::
AddPolygon(
	const BSP_MFace &face
){
	m_faces->push_back(face);			
};


	bool
BSP_CSGMesh::
BuildEdges(
){

	if (m_faces == NULL) return false;

	if (m_edges != NULL) {
		DestroyEdges();
	}

	m_edges = new vector<BSP_MEdge>;

	if (m_edges == NULL) {
		return false;
	}
		

	//iterate through the face set and add edges for all polygon
	//edges
	
	vector<BSP_MFace>::const_iterator f_it_end = FaceSet().end();
	vector<BSP_MFace>::const_iterator f_it_begin = FaceSet().begin();
	vector<BSP_MFace>::iterator f_it = FaceSet().begin();

	vector<BSP_MVertex> & vertex_set = VertexSet();

	vector<BSP_EdgeInd> dummy;

	for (;f_it != f_it_end; ++f_it) {

		BSP_MFace & face = *f_it;

		int vertex_num = face.m_verts.size();
		BSP_VertexInd prev_vi(face.m_verts[vertex_num-1]);

		for (int vert = 0; vert < vertex_num; ++vert) {

			BSP_FaceInd fi(f_it - f_it_begin);
			InsertEdge(prev_vi,face.m_verts[vert],fi,dummy);
			prev_vi = face.m_verts[vert];
		}
			
	}
	dummy.clear();
	return true;
}	
		
	void
BSP_CSGMesh::
DestroyEdges(
){
	m_edges.Delete();
	
	// Run through the vertices
	// and clear their edge arrays.

	if (m_verts){

		vector<BSP_MVertex>::const_iterator vertex_end = VertexSet().end();
		vector<BSP_MVertex>::iterator vertex_it = VertexSet().begin();

		for (; vertex_it != vertex_end; ++vertex_it) {
			vertex_it->m_edges.clear();
		}
	}
}


	BSP_EdgeInd
BSP_CSGMesh::
FindEdge(
	const BSP_VertexInd & v1,
	const BSP_VertexInd & v2
) const {
	
	vector<BSP_MVertex> &verts = VertexSet();
	vector<BSP_MEdge> &edges = EdgeSet();

	BSP_MEdge e;
	e.m_verts[0] = v1;
	e.m_verts[1] = v2;
	
	vector<BSP_EdgeInd> &v1_edges = verts[v1].m_edges;
	vector<BSP_EdgeInd>::const_iterator v1_end = v1_edges.end();
	vector<BSP_EdgeInd>::const_iterator v1_begin = v1_edges.begin();

	for (; v1_begin != v1_end; ++v1_begin) {
		if (edges[*v1_begin] == e) return *v1_begin;
	}
	
	return BSP_EdgeInd::Empty();
}

	void
BSP_CSGMesh::
InsertEdge(
	const BSP_VertexInd & v1,
	const BSP_VertexInd & v2,
	const BSP_FaceInd & f,
	vector<BSP_EdgeInd> &new_edges
){

	MT_assert(!v1.IsEmpty());
	MT_assert(!v2.IsEmpty());
	MT_assert(!f.IsEmpty());

	if (v1.IsEmpty() || v2.IsEmpty() || f.IsEmpty()) {
		BSP_CSGException e(e_mesh_error);
		throw (e);
	}

	vector<BSP_MVertex> &verts = VertexSet();
	vector<BSP_MEdge> &edges = EdgeSet();
	
	BSP_EdgeInd e;

	e = FindEdge(v1,v2);
	if (e.IsEmpty()) {
		// This edge does not exist -- make a new one 

		BSP_MEdge temp_e;
		temp_e.m_verts[0] = v1;
		temp_e.m_verts[1] = v2;

		e = m_edges->size();
		// set the face index from the edge back to this polygon.
		temp_e.m_faces.push_back(f);

		m_edges->push_back(temp_e);

		// add the edge index to it's vertices 
		verts[v1].AddEdge(e);
		verts[v2].AddEdge(e);

		new_edges.push_back(e);

	} else {

		// edge already exists
		// insure that there is no polygon already
		// attached to the other side of this edge
		// swap the empty face pointer in edge with f

		BSP_MEdge &edge = edges[e];

		// set the face index from the edge back to this polygon.
		edge.m_faces.push_back(f);
	}
}		


// geometry access
//////////////////

	vector<BSP_MVertex> &
BSP_CSGMesh::
VertexSet(
) const {
	return m_verts.Ref();
}		

	vector<BSP_MFace> &
BSP_CSGMesh::
FaceSet(
) const {
	return m_faces.Ref();
}

	vector<BSP_MEdge> &
BSP_CSGMesh::
EdgeSet(
) const {
	return m_edges.Ref();
}

	BSP_CSGUserData &
BSP_CSGMesh::
FaceVertexData(
) const {
	return m_fv_data.Ref();
}

	BSP_CSGUserData &
BSP_CSGMesh::
FaceData(
) const {
	return m_face_data.Ref();
}


BSP_CSGMesh::
~BSP_CSGMesh(
){
	// member deletion handled by smart ptr;
}

// local geometry queries.
/////////////////////////

// face queries
///////////////

	void
BSP_CSGMesh::
FaceVertices(
	const BSP_FaceInd & f,
	vector<BSP_VertexInd> &output
){
	vector<BSP_MFace> & face_set = FaceSet();
	output.insert(
		output.end(),
		face_set[f].m_verts.begin(),
		face_set[f].m_verts.end()
	);
}


	void
BSP_CSGMesh::
FaceEdges(
	const BSP_FaceInd & fi,
	vector<BSP_EdgeInd> &output
){
	// take intersection of the edges emminating from all the vertices
	// of this polygon;

	vector<BSP_MFace> &faces = FaceSet();
	vector<BSP_MEdge> &edges = EdgeSet();

	const BSP_MFace & f = faces[fi];

	// collect vertex edges;

	vector<BSP_VertexInd>::const_iterator face_verts_it = f.m_verts.begin();
	vector<BSP_VertexInd>::const_iterator face_verts_end = f.m_verts.end();

	vector< vector<BSP_EdgeInd> > vertex_edges(f.m_verts.size());
		
	int vector_slot = 0;

	for (;face_verts_it != face_verts_end; ++face_verts_it, ++vector_slot) {
		VertexEdges(*face_verts_it,vertex_edges[vector_slot]);
	}	

	int prev = vector_slot - 1; 

	// intersect pairs of edge sets 

	for (int i = 0; i < vector_slot;i++) {
		CTR_TaggedSetOps<BSP_EdgeInd,BSP_MEdge>::IntersectPair(vertex_edges[prev],vertex_edges[i],edges,output);	
		prev = i;
	}
	
	// should always have 3 or more unique edges per face.
	MT_assert(output.size() >=3);

	if (output.size() < 3) {
		BSP_CSGException e(e_mesh_error);
		throw(e);
	}
};
	
// edge queries
///////////////

	void
BSP_CSGMesh::
EdgeVertices(
	const BSP_EdgeInd & e,
	vector<BSP_VertexInd> &output
){
	const vector<BSP_MEdge> &edges = EdgeSet();
	output.push_back(edges[e].m_verts[0]);
	output.push_back(edges[e].m_verts[1]);
} 

	void
BSP_CSGMesh::
EdgeFaces(
	const BSP_EdgeInd & e,
	vector<BSP_FaceInd> &output
){

	vector<BSP_MEdge> & edge_set = EdgeSet();
	output.insert(
		output.end(),
		edge_set[e].m_faces.begin(),
		edge_set[e].m_faces.end()
	);
	
}

// vertex queries
/////////////////

	void
BSP_CSGMesh::
VertexEdges(
	const BSP_VertexInd &v,
	vector<BSP_EdgeInd> &output
){

	vector<BSP_MVertex> & vertex_set = VertexSet();
	output.insert(
		output.end(),
		vertex_set[v].m_edges.begin(),
		vertex_set[v].m_edges.end()
	);
}

	void
BSP_CSGMesh::
VertexFaces(
	const BSP_VertexInd &vi,
	vector<BSP_FaceInd> &output
) {

	vector<BSP_MEdge> &edges = EdgeSet();
	vector<BSP_MFace> &faces = FaceSet();
	vector<BSP_MVertex> &verts = VertexSet();

	const vector<BSP_EdgeInd> &v_edges = verts[vi].m_edges;
	vector<BSP_EdgeInd>::const_iterator e_it = v_edges.begin();

	for (; e_it != v_edges.end(); ++e_it) {

		BSP_MEdge &e = edges[*e_it]; 

		// iterate through the faces of this edge - push unselected
		// edges to ouput and then select the edge

		vector<BSP_FaceInd>::const_iterator e_faces_end = e.m_faces.end();
		vector<BSP_FaceInd>::iterator e_faces_it = e.m_faces.begin();

		for (;e_faces_it != e_faces_end; ++e_faces_it) {

			if (!faces[*e_faces_it].SelectTag()) {
				output.push_back(*e_faces_it);
				faces[*e_faces_it].SetSelectTag(true);
			}
		}
	}

	// deselect selected faces.
	vector<BSP_FaceInd>::iterator f_it = output.begin();

	for (; f_it != output.end(); ++f_it) {
		faces[*f_it].SetSelectTag(false);
	}
}

	void
BSP_CSGMesh::
InsertVertexIntoFace(
	BSP_MFace & face,
	const BSP_VertexInd & v1,
	const BSP_VertexInd & v2,
	const BSP_VertexInd & vi,
	CSG_InterpolateUserFaceVertexDataFunc fv_split_func,
	MT_Scalar epsilon
){
	// We assume that the face vertex data indices
	// are consistent with the vertex inidex data.

	// look for v1
	vector<BSP_VertexInd>::iterator result = 
		find(face.m_verts.begin(),face.m_verts.end(),v1);
	
	MT_assert(result != face.m_verts.end());
	
	BSP_CSGUserData & fv_data = m_fv_data.Ref();

	// now we have to check on either side of the result for the 
	// other vertex
	
	vector<BSP_VertexInd>::iterator prev = result - 1;
	if (prev < face.m_verts.begin()) {	
		prev = face.m_verts.end() -1;
	}
	if (*prev == v2) {

		// so result <=> v2 and prev <=> v1

		// create space for new face vertex data
		
		int vf_i = fv_data.Size();
		fv_data.IncSize();

		int vf_i2 = prev - face.m_verts.begin();
		int vf_i1 = result - face.m_verts.begin();

		(*fv_split_func)(
			fv_data[int(face.m_fv_data[vf_i1])],
			fv_data[int(face.m_fv_data[vf_i2])],
			fv_data[vf_i],
			epsilon
		);
	
		// insert vertex data index.
		face.m_fv_data.insert(face.m_fv_data.begin() + vf_i1,vf_i);
		face.m_verts.insert(result,vi);

		return;
	}

	vector<BSP_VertexInd>::iterator next = result + 1;
	if (next >= face.m_verts.end()) {	
		next = face.m_verts.begin();
	}
	if (*next == v2) {

		// so result <=> v1 and next <=> v2

		int vf_i = fv_data.Size();
		fv_data.IncSize();

		int vf_i2 = int(next - face.m_verts.begin());
		int vf_i1 = int(result - face.m_verts.begin());

		(*fv_split_func)(
			fv_data[int(face.m_fv_data[vf_i1])],
			fv_data[int(face.m_fv_data[vf_i2])],
			fv_data[vf_i],
			epsilon
		);

		// insert vertex data index.
		face.m_fv_data.insert(face.m_fv_data.begin() + vf_i2,vf_i);
		face.m_verts.insert(next,vi);

		return;
	}

	// if we get here we are in trouble.
	MT_assert(false);
	BSP_CSGException e(e_mesh_error);
	throw(e);
}

	void
BSP_CSGMesh::
SetBBox(
	const MT_Vector3 & min,
	const MT_Vector3 & max
){
	m_bbox_min = min;
	m_bbox_max = max;
}


	void
BSP_CSGMesh::
BBox(
	MT_Vector3 &min,
	MT_Vector3 &max
) const {
	min = m_bbox_min;
	max = m_bbox_max;
}


// Update the BBox
//////////////////

	void
BSP_CSGMesh::
UpdateBBox(
){
	// TODO
};

	void
BSP_CSGMesh::
SC_Classification(
	BSP_FaceInd f,
	const MT_Plane3& plane
){
	const BSP_MFace & face = FaceSet()[f];

	vector<BSP_VertexInd>::const_iterator f_verts_it = face.m_verts.begin();
	vector<BSP_VertexInd>::const_iterator f_verts_end = face.m_verts.end();

	for (;f_verts_it != f_verts_end; ++f_verts_it) {

		const BSP_MVertex & vert = VertexSet()[*f_verts_it];

		MT_Scalar dist = plane.signedDistance(
			vert.m_pos
		);

		if (fabs(dist) <= BSP_SPLIT_EPSILON ){
			MT_assert(BSP_Classification(vert.OpenTag()) == e_classified_on);
		} else
		if (dist > BSP_SPLIT_EPSILON) {
			MT_assert(BSP_Classification(vert.OpenTag()) == e_classified_out);
		} else 
		if (dist < BSP_SPLIT_EPSILON) {
			MT_assert(BSP_Classification(vert.OpenTag()) == e_classified_in);
		}
	}
}


	bool
BSP_CSGMesh::
SC_Face(
	BSP_FaceInd f
){



#if 0
	{
	// check area is greater than zero.

		vector<BSP_MVertex> & verts = VertexSet();

		vector<BSP_VertexInd> f_verts;
		FaceVertices(f,f_verts);

		MT_assert(f_verts.size() >= 3);

		BSP_VertexInd root = f_verts[0];
		
		MT_Scalar area = 0;

		for (int i=2; i < f_verts.size(); i++) {
			MT_Vector3 a = verts[root].m_pos;
			MT_Vector3 b = verts[f_verts[i-1]].m_pos;
			MT_Vector3 c = verts[f_verts[i]].m_pos;

			MT_Vector3 l1 = b-a;
			MT_Vector3 l2 = c-b;

			area += (l1.cross(l2)).length()/2;
		}

		MT_assert(!MT_fuzzyZero(area));
	}
#endif
	// Check coplanarity 
#if 0
	MT_Plane3 plane = FacePlane(f);

	const BSP_MFace & face = FaceSet()[f];
	vector<BSP_VertexInd>::const_iterator f_verts_it = face.m_verts.begin();
	vector<BSP_VertexInd>::const_iterator f_verts_end = face.m_verts.end();

	for (;f_verts_it != f_verts_end; ++f_verts_it) {
		MT_Scalar dist = plane.signedDistance(
			VertexSet()[*f_verts_it].m_pos
		);

		MT_assert(fabs(dist) < BSP_SPLIT_EPSILON);
	}
#endif


	// Check connectivity

	vector<BSP_EdgeInd> f_edges;	
	FaceEdges(f,f_edges);

	MT_assert(f_edges.size() == FaceSet()[f].m_verts.size());

	unsigned int i;
	for (i = 0; i < f_edges.size(); ++i) {

		int matches = 0;
		for (unsigned int j = 0; j < EdgeSet()[f_edges[i]].m_faces.size(); j++) {

			if (EdgeSet()[f_edges[i]].m_faces[j] == f) matches++;
		}

		MT_assert(matches == 1);

	}	
	return true;
}	

	MT_Plane3
BSP_CSGMesh::
FacePlane(
	const BSP_FaceInd & fi
) const{

	const BSP_MFace & f0 = FaceSet()[fi]; 	

	// Have to be a bit careful here coz the poly may have 
	// a lot of parallel edges. Should walk round the polygon
	// and check length of cross product.

	const MT_Vector3 & p1 = VertexSet()[f0.m_verts[0]].m_pos;
	const MT_Vector3 & p2 = VertexSet()[f0.m_verts[1]].m_pos;

	int face_size = f0.m_verts.size();
	MT_Vector3 n;

	for (int i = 2 ; i <face_size; i++) { 
		const MT_Vector3 & pi =  VertexSet()[f0.m_verts[i]].m_pos;
		
		MT_Vector3 l1 = p2-p1;
		MT_Vector3 l2 = pi-p2;
		n = l1.cross(l2);
		MT_Scalar length = n.length();

		if (!MT_fuzzyZero(length)) {
			n = n * (1/length);
			break;
		} 
	}
	return MT_Plane3(n,p1);
}

	void
BSP_CSGMesh::
ComputeFacePlanes(
){

	int fsize = FaceSet().size();
	int i=0;
	for (i = 0; i < fsize; i++) {
	
		FaceSet()[i].m_plane = FacePlane(i);
	}
};


	int
BSP_CSGMesh::
CountTriangles(
) const {

	// Each polygon of n sides can be partitioned into n-3 triangles.
	// So we just go through and sum this function of polygon size.
	
	vector<BSP_MFace> & face_set = FaceSet();

	vector<BSP_MFace>::const_iterator face_it = face_set.begin();
	vector<BSP_MFace>::const_iterator face_end = face_set.end();

	int sum = 0;

	for (;face_it != face_end; face_it++) {
	
		// Should be careful about degenerate faces here.
		sum += face_it->m_verts.size() - 2;
	}

	return sum;
}