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source: trunk/VUT/GtpVisibilityPreprocessor/src/ViewCellBsp.cpp @ 605

Revision 605, 75.0 KB checked in by mattausch, 19 years ago (diff)

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1	#include "Plane3.h"
2	#include "ViewCellBsp.h"
3	#include "Mesh.h"
4	#include "common.h"
5	#include "ViewCell.h"
6	#include "Environment.h"
7	#include "Polygon3.h"
8	#include "Ray.h"
9	#include "AxisAlignedBox3.h"
10	#include "Triangle3.h"
11	#include "Tetrahedron3.h"
12	#include "ViewCellsManager.h"
13	#include "Exporter.h"
14	#include "Plane3.h"
15	#include <stack>
16
17
18
19	//-- static members
20
21	int BspNode::sMailId = 1;
22
23	/** Evaluates split plane classification with respect to the plane's
24	contribution for a minimum number splits in the tree.
25	*/
26	const float BspTree::sLeastPolySplitsTable[] = {0, 0, 1, 0};
27	/** Evaluates split plane classification with respect to the plane's
28	contribution for a balanced tree.
29	*/
30	const float BspTree::sBalancedPolysTable[] = {1, -1, 0, 0};
31
32	/** Evaluates split plane classification with respect to the plane's
33	contribution for a minimum number of ray splits.
34	*/
35	const float BspTree::sLeastRaySplitsTable[] = {0, 0, 1, 1, 0};
36	/** Evaluates split plane classification with respect to the plane's
37	contribution for balanced rays.
38	*/
39	const float BspTree::sBalancedRaysTable[] = {1, -1, 0, 0, 0};
40
41	int BspTree::sFrontId = 0;
42	int BspTree::sBackId = 0;
43	int BspTree::sFrontAndBackId = 0;
44
45
46	/****************************************************************/
47	/* class BspNode implementation */
48	/****************************************************************/
49
50
51	BspNode::BspNode():
52	mParent(NULL), mTreeValid(true)
53	{}
54
55	BspNode::BspNode(BspInterior *parent):
56	mParent(parent), mTreeValid(true)
57	{}
58
59
60	bool BspNode::IsRoot() const
61	{
62	return mParent == NULL;
63	}
64
65
66	BspInterior *BspNode::GetParent()
67	{
68	return mParent;
69	}
70
71
72	void BspNode::SetParent(BspInterior *parent)
73	{
74	mParent = parent;
75	}
76
77
78	bool BspNode::IsSibling(BspNode *n) const
79	{
80	return ((this != n) && mParent &&
81	(mParent->GetFront() == n) \|\| (mParent->GetBack() == n));
82	}
83
84
85	int BspNode::GetDepth() const
86	{
87	int depth = 0;
88	BspNode *p = mParent;
89
90	while (p)
91	{
92	p = p->mParent;
93	++ depth;
94	}
95
96	return depth;
97	}
98
99
100	bool BspNode::TreeValid() const
101	{
102	return mTreeValid;
103	}
104
105
106	void BspNode::SetTreeValid(const bool v)
107	{
108	mTreeValid = v;
109	}
110
111
112	/****************************************************************/
113	/* class BspInterior implementation */
114	/****************************************************************/
115
116
117	BspInterior::BspInterior(const Plane3 &plane):
118	mPlane(plane), mFront(NULL), mBack(NULL)
119	{}
120
121	BspInterior::~BspInterior()
122	{
123	DEL_PTR(mFront);
124	DEL_PTR(mBack);
125	}
126
127	bool BspInterior::IsLeaf() const
128	{
129	return false;
130	}
131
132	BspNode *BspInterior::GetBack()
133	{
134	return mBack;
135	}
136
137	BspNode *BspInterior::GetFront()
138	{
139	return mFront;
140	}
141
142	Plane3 BspInterior::GetPlane() const
143	{
144	return mPlane;
145	}
146
147	void BspInterior::ReplaceChildLink(BspNode oldChild, BspNode newChild)
148	{
149	if (mBack == oldChild)
150	mBack = newChild;
151	else
152	mFront = newChild;
153	}
154
155	void BspInterior::SetupChildLinks(BspNode b, BspNode f)
156	{
157	mBack = b;
158	mFront = f;
159	}
160
161	/****************************************************************/
162	/* class BspLeaf implementation */
163	/****************************************************************/
164
165
166	BspLeaf::BspLeaf(): mViewCell(NULL), mPvs(NULL)
167	{
168	}
169
170
171	BspLeaf::~BspLeaf()
172	{
173	DEL_PTR(mPvs);
174	}
175
176
177	BspLeaf::BspLeaf(ViewCell *viewCell):
178	mViewCell(viewCell)
179	{
180	}
181
182
183	BspLeaf::BspLeaf(BspInterior *parent):
184	BspNode(parent), mViewCell(NULL), mPvs(NULL)
185	{}
186
187
188
189	BspLeaf::BspLeaf(BspInterior parent, ViewCell viewCell):
190	BspNode(parent), mViewCell(viewCell), mPvs(NULL)
191	{
192	}
193
194	ViewCell *BspLeaf::GetViewCell() const
195	{
196	return mViewCell;
197	}
198
199	void BspLeaf::SetViewCell(ViewCell *viewCell)
200	{
201	mViewCell = viewCell;
202	}
203
204
205	bool BspLeaf::IsLeaf() const
206	{
207	return true;
208	}
209
210
211	/*********************************************************************/
212	/* class BspTree implementation */
213	/*********************************************************************/
214
215	BspTree::BspTree():
216	mRoot(NULL),
217	mUseAreaForPvs(false),
218	mGenerateViewCells(true)
219	{
220	Randomize(); // initialise random generator for heuristics
221
222	mOutOfBoundsCell = GetOrCreateOutOfBoundsCell();
223
224	//-- termination criteria for autopartition
225	environment->GetIntValue("BspTree.Termination.maxDepth", mTermMaxDepth);
226	environment->GetIntValue("BspTree.Termination.minPvs", mTermMinPvs);
227	environment->GetIntValue("BspTree.Termination.minPolygons", mTermMinPolys);
228	environment->GetIntValue("BspTree.Termination.minRays", mTermMinRays);
229	environment->GetFloatValue("BspTree.Termination.minProbability", mTermMinProbability);
230	environment->GetFloatValue("BspTree.Termination.maxRayContribution", mTermMaxRayContribution);
231	environment->GetFloatValue("BspTree.Termination.minAccRayLenght", mTermMinAccRayLength);
232
233	//-- factors for bsp tree split plane heuristics
234	environment->GetFloatValue("BspTree.Factor.verticalSplits", mVerticalSplitsFactor);
235	environment->GetFloatValue("BspTree.Factor.largestPolyArea", mLargestPolyAreaFactor);
236	environment->GetFloatValue("BspTree.Factor.blockedRays", mBlockedRaysFactor);
237	environment->GetFloatValue("BspTree.Factor.leastRaySplits", mLeastRaySplitsFactor);
238	environment->GetFloatValue("BspTree.Factor.balancedRays", mBalancedRaysFactor);
239	environment->GetFloatValue("BspTree.Factor.pvs", mPvsFactor);
240	environment->GetFloatValue("BspTree.Factor.leastSplits" , mLeastSplitsFactor);
241	environment->GetFloatValue("BspTree.Factor.balancedPolys", mBalancedPolysFactor);
242	environment->GetFloatValue("BspTree.Factor.balancedViewCells", mBalancedViewCellsFactor);
243	environment->GetFloatValue("BspTree.Termination.ct_div_ci", mCtDivCi);
244
245	//-- termination criteria for axis aligned split
246	environment->GetFloatValue("BspTree.Termination.AxisAligned.ct_div_ci", mAxisAlignedCtDivCi);
247	environment->GetFloatValue("BspTree.Termination.maxCostRatio", mMaxCostRatio);
248	environment->GetIntValue("BspTree.Termination.AxisAligned.minPolys",
249	mTermMinPolysForAxisAligned);
250	environment->GetIntValue("BspTree.Termination.AxisAligned.minRays",
251	mTermMinRaysForAxisAligned);
252	environment->GetIntValue("BspTree.Termination.AxisAligned.minObjects",
253	mTermMinObjectsForAxisAligned);
254	//-- partition criteria
255	environment->GetIntValue("BspTree.maxPolyCandidates", mMaxPolyCandidates);
256	environment->GetIntValue("BspTree.maxRayCandidates", mMaxRayCandidates);
257	environment->GetIntValue("BspTree.splitPlaneStrategy", mSplitPlaneStrategy);
258	environment->GetFloatValue("BspTree.AxisAligned.splitBorder", mSplitBorder);
259	environment->GetIntValue("BspTree.maxTests", mMaxTests);
260	environment->GetIntValue("BspTree.Termination.maxViewCells", mMaxViewCells);
261
262	environment->GetFloatValue("BspTree.Construction.epsilon", mEpsilon);
263
264	Debug << "BSP max depth: " << mTermMaxDepth << endl;
265	Debug << "BSP min PVS: " << mTermMinPvs << endl;
266	Debug << "BSP min probability: " << mTermMinProbability << endl;
267	Debug << "BSP max polys: " << mTermMinPolys << endl;
268	Debug << "BSP max rays: " << mTermMinRays << endl;
269	Debug << "BSP max polygon candidates: " << mMaxPolyCandidates << endl;
270	Debug << "BSP max plane candidates: " << mMaxRayCandidates << endl;
271
272	Debug << "Split plane strategy: ";
273	if (mSplitPlaneStrategy & RANDOM_POLYGON)
274	Debug << "random polygon ";
275	if (mSplitPlaneStrategy & AXIS_ALIGNED)
276	Debug << "axis aligned ";
277	if (mSplitPlaneStrategy & LEAST_SPLITS)
278	Debug << "least splits ";
279	if (mSplitPlaneStrategy & BALANCED_POLYS)
280	Debug << "balanced polygons ";
281	if (mSplitPlaneStrategy & BALANCED_VIEW_CELLS)
282	Debug << "balanced view cells ";
283	if (mSplitPlaneStrategy & LARGEST_POLY_AREA)
284	Debug << "largest polygon area ";
285	if (mSplitPlaneStrategy & VERTICAL_AXIS)
286	Debug << "vertical axis ";
287	if (mSplitPlaneStrategy & BLOCKED_RAYS)
288	Debug << "blocked rays ";
289	if (mSplitPlaneStrategy & LEAST_RAY_SPLITS)
290	Debug << "least ray splits ";
291	if (mSplitPlaneStrategy & BALANCED_RAYS)
292	Debug << "balanced rays ";
293	if (mSplitPlaneStrategy & PVS)
294	Debug << "pvs";
295
296	Debug << endl;
297	}
298
299
300	const BspTreeStatistics &BspTree::GetStatistics() const
301	{
302	return mStat;
303	}
304
305
306	int BspTree::SplitPolygons(const Plane3 &plane,
307	PolygonContainer &polys,
308	PolygonContainer &frontPolys,
309	PolygonContainer &backPolys,
310	PolygonContainer &coincident) const
311	{
312	int splits = 0;
313
314	#ifdef _Debug
315	Debug << "splitting polygons of node " << this << " with plane " << mPlane << endl;
316	#endif
317	PolygonContainer::const_iterator it, it_end = polys.end();
318
319	for (it = polys.begin(); it != polys.end(); ++ it)
320	{
321	Polygon3 poly = it;
322
323	//-- classify polygon
324	const int cf = poly->ClassifyPlane(plane, mEpsilon);
325
326	switch (cf)
327	{
328	case Polygon3::COINCIDENT:
329	coincident.push_back(poly);
330	break;
331	case Polygon3::FRONT_SIDE:
332	frontPolys.push_back(poly);
333	break;
334	case Polygon3::BACK_SIDE:
335	backPolys.push_back(poly);
336	break;
337	case Polygon3::SPLIT:
338	{
339	Polygon3 *front_piece = new Polygon3(poly->mParent);
340	Polygon3 *back_piece = new Polygon3(poly->mParent);
341
342	//-- split polygon into front and back part
343	poly->Split(plane,
344	*front_piece,
345	*back_piece,
346	mEpsilon);
347
348	++ splits; // increase number of splits
349
350	//-- inherit rays from parent polygon for blocked ray criterium
351	poly->InheritRays(front_piece, back_piece);
352
353	// check if polygons still valid
354	if (front_piece->Valid(mEpsilon))
355	frontPolys.push_back(front_piece);
356	else
357	DEL_PTR(front_piece);
358
359	if (back_piece->Valid(mEpsilon))
360	backPolys.push_back(back_piece);
361	else
362	DEL_PTR(back_piece);
363
364	#ifdef _DEBUG
365	Debug << "split " << poly << endl << front_piece << endl << *back_piece << endl;
366	#endif
367	DEL_PTR(poly);
368	}
369	break;
370	default:
371	Debug << "SHOULD NEVER COME HERE\n";
372	break;
373	}
374	}
375
376	return splits;
377	}
378
379
380	void BspTreeStatistics::Print(ostream &app) const
381	{
382	app << "===== BspTree statistics ===============\n";
383
384	app << setprecision(4);
385
386	app << "#N_CTIME ( Construction time [s] )\n" << Time() << " \n";
387
388	app << "#N_NODES ( Number of nodes )\n" << nodes << "\n";
389
390	app << "#N_INTERIORS ( Number of interior nodes )\n" << Interior() << "\n";
391
392	app << "#N_LEAVES ( Number of leaves )\n" << Leaves() << "\n";
393
394	app << "#N_POLYSPLITS ( Number of polygon splits )\n" << polySplits << "\n";
395
396	app << "#AXIS_ALIGNED_SPLITS (number of axis aligned splits)\n" << splits[0] + splits[1] + splits[2] << endl;
397
398	app << "#N_SPLITS ( Number of splits in axes x y z\n";
399
400	for (int i = 0; i < 3; ++ i)
401	app << splits[i] << " ";
402	app << endl;
403
404	app << "#N_PMAXDEPTHLEAVES ( Percentage of leaves at maximum depth )\n"
405	<< maxDepthNodes * 100 / (double)Leaves() << endl;
406
407	app << "#N_PMINPVSLEAVES ( Percentage of leaves with mininimal PVS )\n"
408	<< minPvsNodes * 100 / (double)Leaves() << endl;
409
410	app << "#N_PMINRAYSLEAVES ( Percentage of leaves with minimal number of rays)\n"
411	<< minRaysNodes * 100 / (double)Leaves() << endl;
412
413	app << "#N_MAXCOSTNODES ( Percentage of leaves with terminated because of max cost ratio )\n"
414	<< maxCostNodes * 100 / (double)Leaves() << endl;
415
416	app << "#N_PMINPROBABILITYLEAVES ( Percentage of leaves with mininum probability )\n"
417	<< minProbabilityNodes * 100 / (double)Leaves() << endl;
418
419	app << "#N_PMAXRAYCONTRIBLEAVES ( Percentage of leaves with maximal ray contribution )\n"
420	<< maxRayContribNodes * 100 / (double)Leaves() << endl;
421
422	app << "#N_PMAXDEPTH ( Maximal reached depth )\n" << maxDepth << endl;
423
424	app << "#N_PMINDEPTH ( Minimal reached depth )\n" << minDepth << endl;
425
426	app << "#AVGDEPTH ( average depth )\n" << AvgDepth() << endl;
427
428	app << "#N_INPUTPOLYGONS (number of input polygons )\n" << polys << endl;
429
430	app << "#N_INVALIDLEAVES (number of invalid leaves )\n" << invalidLeaves << endl;
431
432	app << "#N_RAYS (number of rays / leaf)\n" << AvgRays() << endl;
433	//app << "#N_PVS: " << pvs << endl;
434
435	app << "#N_ROUTPUT_INPUT_POLYGONS ( ratio polygons after subdivision / input polygons )\n" <<
436	(polys + polySplits) / (double)polys << endl;
437
438	app << "===== END OF BspTree statistics ==========\n";
439	}
440
441
442	BspTree::~BspTree()
443	{
444	DEL_PTR(mRoot);
445
446	// TODO must be deleted if used!!
447	//if (mGenerateViewCells) DEL_PTR(mOutOfBoundsCell);
448	}
449
450	BspViewCell *BspTree::GetOutOfBoundsCell()
451	{
452	return mOutOfBoundsCell;
453	}
454
455
456	BspNode *BspTree::GetRoot() const
457	{
458	return mRoot;
459	}
460
461	BspViewCell *BspTree::GetOrCreateOutOfBoundsCell()
462	{
463	if (!mOutOfBoundsCell)
464	{
465	mOutOfBoundsCell = new BspViewCell();
466	mOutOfBoundsCell->SetId(-1);
467	mOutOfBoundsCell->SetValid(false);
468	}
469
470	return mOutOfBoundsCell;
471	}
472
473
474	void BspTree::InsertViewCell(ViewCell *viewCell)
475	{
476	PolygonContainer *polys = new PolygonContainer();
477
478	// don't generate new view cell, insert this one
479	mGenerateViewCells = false;
480	// extract polygons that guide the split process
481	mStat.polys += AddMeshToPolygons(viewCell->GetMesh(), *polys, viewCell);
482	mBox.Include(viewCell->GetBox()); // add to BSP aabb
483
484	InsertPolygons(polys);
485	}
486
487
488	void BspTree::InsertPolygons(PolygonContainer *polys)
489	{
490	BspTraversalStack tStack;
491
492	// traverse existing tree or create new tree
493	if (!mRoot)
494	mRoot = new BspLeaf();
495
496	tStack.push(BspTraversalData(mRoot,
497	polys,
498	0,
499	mOutOfBoundsCell,
500	new BoundedRayContainer(),
501	0,
502	mUseAreaForPvs ? mBox.SurfaceArea() : mBox.GetVolume(),
503	new BspNodeGeometry()));
504
505	while (!tStack.empty())
506	{
507	// filter polygons donw the tree
508	BspTraversalData tData = tStack.top();
509	tStack.pop();
510
511	if (!tData.mNode->IsLeaf())
512	{
513	BspInterior interior = dynamic_cast<BspInterior >(tData.mNode);
514
515	//-- filter view cell polygons down the tree until a leaf is reached
516	if (!tData.mPolygons->empty())
517	{
518	PolygonContainer *frontPolys = new PolygonContainer();
519	PolygonContainer *backPolys = new PolygonContainer();
520	PolygonContainer coincident;
521
522	int splits = 0;
523
524	// split viewcell polygons with respect to split plane
525	splits += SplitPolygons(interior->GetPlane(),
526	*tData.mPolygons,
527	*frontPolys,
528	*backPolys,
529	coincident);
530
531	// extract view cells associated with the split polygons
532	ViewCell *frontViewCell = GetOrCreateOutOfBoundsCell();
533	ViewCell *backViewCell = GetOrCreateOutOfBoundsCell();
534
535	BspTraversalData frontData(interior->GetFront(),
536	frontPolys,
537	tData.mDepth + 1,
538	mOutOfBoundsCell,
539	tData.mRays,
540	tData.mPvs,
541	mUseAreaForPvs ? mBox.SurfaceArea() : mBox.GetVolume(),
542	new BspNodeGeometry());
543
544	BspTraversalData backData(interior->GetBack(),
545	backPolys,
546	tData.mDepth + 1,
547	mOutOfBoundsCell,
548	tData.mRays,
549	tData.mPvs,
550	mUseAreaForPvs ? mBox.SurfaceArea() : mBox.GetVolume(),
551	new BspNodeGeometry());
552
553	if (!mGenerateViewCells)
554	{
555	ExtractViewCells(frontData,
556	backData,
557	coincident,
558	interior->mPlane);
559	}
560
561	// don't need coincident polygons anymore
562	CLEAR_CONTAINER(coincident);
563
564	mStat.polySplits += splits;
565
566	// push the children on the stack
567	tStack.push(frontData);
568	tStack.push(backData);
569	}
570
571	// cleanup
572	DEL_PTR(tData.mPolygons);
573	DEL_PTR(tData.mRays);
574	}
575	else
576	{
577	// reached leaf => subdivide current viewcell
578	BspNode *subRoot = Subdivide(tStack, tData);
579	}
580	}
581	}
582
583	int BspTree::AddMeshToPolygons(Mesh *mesh,
584	PolygonContainer &polys,
585	MeshInstance *parent)
586	{
587	FaceContainer::const_iterator fi;
588
589	// copy the face data to polygons
590	for (fi = mesh->mFaces.begin(); fi != mesh->mFaces.end(); ++ fi)
591	{
592	Polygon3 poly = new Polygon3((fi), mesh);
593
594	if (poly->Valid(mEpsilon))
595	{
596	poly->mParent = parent; // set parent intersectable
597	polys.push_back(poly);
598	}
599	else
600	DEL_PTR(poly);
601	}
602	return (int)mesh->mFaces.size();
603	}
604
605
606	int BspTree::AddToPolygonSoup(const ViewCellContainer &viewCells,
607	PolygonContainer &polys,
608	int maxObjects)
609	{
610	int limit = (maxObjects > 0) ?
611	Min((int)viewCells.size(), maxObjects) : (int)viewCells.size();
612
613	int polysSize = 0;
614
615	for (int i = 0; i < limit; ++ i)
616	{
617	if (viewCells[i]->GetMesh()) // copy the mesh data to polygons
618	{
619	mBox.Include(viewCells[i]->GetBox()); // add to BSP tree aabb
620	polysSize += AddMeshToPolygons(viewCells[i]->GetMesh(), polys, viewCells[i]);
621	}
622	}
623
624	return polysSize;
625	}
626
627
628	int BspTree::AddToPolygonSoup(const ObjectContainer &objects,
629	PolygonContainer &polys,
630	int maxObjects,
631	bool addToBbox)
632	{
633	int limit = (maxObjects > 0) ?
634	Min((int)objects.size(), maxObjects) : (int)objects.size();
635
636	for (int i = 0; i < limit; ++i)
637	{
638	Intersectable object = objects[i];//it;
639	Mesh *mesh = NULL;
640
641	switch (object->Type()) // extract the meshes
642	{
643	case Intersectable::MESH_INSTANCE:
644	mesh = dynamic_cast<MeshInstance *>(object)->GetMesh();
645	break;
646	case Intersectable::VIEW_CELL:
647	mesh = dynamic_cast<ViewCell *>(object)->GetMesh();
648	break;
649	// TODO: handle transformed mesh instances
650	default:
651	Debug << "intersectable type not supported" << endl;
652	break;
653	}
654
655	if (mesh) // copy the mesh data to polygons
656	{
657	if (addToBbox)
658	{
659	mBox.Include(object->GetBox()); // add to BSP tree aabb
660	}
661
662	AddMeshToPolygons(mesh, polys, mOutOfBoundsCell);
663	}
664	}
665
666	return (int)polys.size();
667	}
668
669
670	void BspTree::Construct(const ViewCellContainer &viewCells)
671	{
672	mStat.nodes = 1;
673	mBox.Initialize(); // initialise bsp tree bounding box
674
675	// copy view cell meshes into one big polygon soup
676	PolygonContainer *polys = new PolygonContainer();
677	mStat.polys = AddToPolygonSoup(viewCells, *polys);
678
679	// view cells are given
680	mGenerateViewCells = false;
681	// construct tree from the view cell polygons
682	Construct(polys, new BoundedRayContainer());
683	}
684
685
686	void BspTree::Construct(const ObjectContainer &objects)
687	{
688	mStat.nodes = 1;
689	mBox.Initialize(); // initialise bsp tree bounding box
690
691	PolygonContainer *polys = new PolygonContainer();
692
693	mGenerateViewCells = true;
694	// copy mesh instance polygons into one big polygon soup
695	mStat.polys = AddToPolygonSoup(objects, *polys);
696
697	// construct tree from polygon soup
698	Construct(polys, new BoundedRayContainer());
699	}
700
701
702	void BspTree::Construct(const RayContainer &sampleRays,
703	AxisAlignedBox3 *forcedBoundingBox)
704	{
705	mStat.nodes = 1;
706	mBox.Initialize(); // initialise BSP tree bounding box
707
708	if (forcedBoundingBox)
709	mBox = *forcedBoundingBox;
710
711	PolygonContainer *polys = new PolygonContainer();
712	BoundedRayContainer *rays = new BoundedRayContainer();
713
714	RayContainer::const_iterator rit, rit_end = sampleRays.end();
715
716	// generate view cells
717	mGenerateViewCells = true;
718
719	long startTime = GetTime();
720
721	Debug << "** Extracting polygons from rays **\n";
722
723	std::map<Face , Polygon3 > facePolyMap;
724
725	//-- extract polygons intersected by the rays
726	for (rit = sampleRays.begin(); rit != rit_end; ++ rit)
727	{
728	Ray ray = rit;
729
730	// get ray-face intersection. Store polygon representing the rays together
731	// with rays intersecting the face.
732	if (!ray->intersections.empty())
733	{
734	MeshInstance obj = dynamic_cast<MeshInstance >(ray->intersections[0].mObject);
735	Face *face = obj->GetMesh()->mFaces[ray->intersections[0].mFace];
736
737	std::map<Face , Polygon3 >::iterator it = facePolyMap.find(face);
738
739	if (it != facePolyMap.end())
740	{
741	//store rays if needed for heuristics
742	if (mSplitPlaneStrategy & BLOCKED_RAYS)
743	(*it).second->mPiercingRays.push_back(ray);
744	}
745	else
746	{ //store rays if needed for heuristics
747	Polygon3 *poly = new Polygon3(face, obj->GetMesh());
748	poly->mParent = obj;
749	polys->push_back(poly);
750
751	if (mSplitPlaneStrategy & BLOCKED_RAYS)
752	poly->mPiercingRays.push_back(ray);
753
754	facePolyMap[face] = poly;
755	}
756	}
757	}
758
759	facePolyMap.clear();
760
761	// compute bounding box
762	if (!forcedBoundingBox)
763	Polygon3::IncludeInBox(*polys, mBox);
764
765	//-- store rays
766	for (rit = sampleRays.begin(); rit != rit_end; ++ rit)
767	{
768	Ray ray = rit;
769	ray->SetId(-1); // reset id
770
771	float minT, maxT;
772	if (mBox.GetRaySegment(*ray, minT, maxT))
773	rays->push_back(new BoundedRay(ray, minT, maxT));
774	}
775
776	mStat.polys = (int)polys->size();
777
778	Debug << "** Finished polygon extraction **" << endl;
779	Debug << (int)polys->size() << " polys extracted from " << (int)sampleRays.size() << " rays" << endl;
780	Debug << "extraction time: " << TimeDiff(startTime, GetTime())*1e-3 << "s" << endl;
781
782	Construct(polys, rays);
783	}
784
785
786	void BspTree::Construct(const ObjectContainer &objects,
787	const RayContainer &sampleRays,
788	AxisAlignedBox3 *forcedBoundingBox)
789	{
790	mStat.nodes = 1;
791	mBox.Initialize(); // initialise BSP tree bounding box
792
793	if (forcedBoundingBox)
794	mBox = *forcedBoundingBox;
795
796	BoundedRayContainer *rays = new BoundedRayContainer();
797	PolygonContainer *polys = new PolygonContainer();
798
799	mGenerateViewCells = true;
800
801	// copy mesh instance polygons into one big polygon soup
802	mStat.polys = AddToPolygonSoup(objects, *polys, 0, !forcedBoundingBox);
803
804
805	RayContainer::const_iterator rit, rit_end = sampleRays.end();
806
807	//-- store rays
808	for (rit = sampleRays.begin(); rit != rit_end; ++ rit)
809	{
810	Ray ray = rit;
811	ray->SetId(-1); // reset id
812
813	float minT, maxT;
814	if (mBox.GetRaySegment(*ray, minT, maxT))
815	rays->push_back(new BoundedRay(ray, minT, maxT));
816	}
817
818	Debug << "tree has " << (int)polys->size() << " polys, " << (int)sampleRays.size() << " rays" << endl;
819	Construct(polys, rays);
820	}
821
822
823	void BspTree::Construct(PolygonContainer polys, BoundedRayContainer rays)
824	{
825	BspTraversalStack tStack;
826
827	mRoot = new BspLeaf();
828
829	// constrruct root node geometry
830	BspNodeGeometry *geom = new BspNodeGeometry();
831	ConstructGeometry(mRoot, *geom);
832
833	BspTraversalData tData(mRoot,
834	polys,
835	0,
836	GetOrCreateOutOfBoundsCell(),
837	rays,
838	ComputePvsSize(*rays),
839	mUseAreaForPvs ? geom->GetArea() : geom->GetVolume(),
840	geom);
841
842	tStack.push(tData);
843
844	mStat.Start();
845	cout << "Contructing bsp tree ... ";
846	long startTime = GetTime();
847	while (!tStack.empty())
848	{
849	tData = tStack.top();
850
851	tStack.pop();
852
853	// subdivide leaf node
854	BspNode *r = Subdivide(tStack, tData);
855
856	if (r == mRoot)
857	Debug << "BSP tree construction time spent at root: "
858	<< TimeDiff(startTime, GetTime())*1e-3 << " secs" << endl;
859	}
860
861	cout << "finished\n";
862
863	mStat.Stop();
864	}
865
866
867	bool BspTree::TerminationCriteriaMet(const BspTraversalData &data) const
868	{
869	return
870	(((int)data.mPolygons->size() <= mTermMinPolys) \|\|
871	((int)data.mRays->size() <= mTermMinRays) \|\|
872	(data.mPvs <= mTermMinPvs) \|\|
873	(data.mProbability <= mTermMinProbability) \|\|
874	(data.mDepth >= mTermMaxDepth) \|\|
875	(mStat.Leaves() >= mMaxViewCells) \|\|
876	(data.GetAvgRayContribution() > mTermMaxRayContribution));
877	}
878
879
880	BspNode *BspTree::Subdivide(BspTraversalStack &tStack, BspTraversalData &tData)
881	{
882	//-- terminate traversal
883	if (TerminationCriteriaMet(tData))
884	{
885	BspLeaf leaf = dynamic_cast<BspLeaf >(tData.mNode);
886
887	BspViewCell *viewCell;
888
889	// generate new view cell for each leaf
890	if (mGenerateViewCells)
891	viewCell = new BspViewCell();
892	else
893	// add view cell to leaf
894	viewCell = dynamic_cast<BspViewCell *>(tData.mViewCell);
895
896	leaf->SetViewCell(viewCell);
897	viewCell->mLeaf = leaf;
898
899	if (mUseAreaForPvs)
900	viewCell->SetArea(tData.mProbability);
901	else
902	viewCell->SetVolume(tData.mProbability);
903
904	//-- add pvs
905	if (viewCell != mOutOfBoundsCell)
906	{
907	int conSamp = 0, sampCon = 0;
908	AddToPvs(leaf, *tData.mRays, conSamp, sampCon);
909
910	mStat.contributingSamples += conSamp;
911	mStat.sampleContributions += sampCon;
912	}
913
914	EvaluateLeafStats(tData);
915
916	//-- clean up
917
918	// discard polygons
919	CLEAR_CONTAINER(*tData.mPolygons);
920	// discard rays
921	CLEAR_CONTAINER(*tData.mRays);
922
923	DEL_PTR(tData.mPolygons);
924	DEL_PTR(tData.mRays);
925	DEL_PTR(tData.mGeometry);
926
927	return leaf;
928	}
929
930	//-- continue subdivision
931	PolygonContainer coincident;
932
933	BspTraversalData tFrontData(NULL, new PolygonContainer(), tData.mDepth + 1, mOutOfBoundsCell,
934	new BoundedRayContainer(), 0, 0, new BspNodeGeometry());
935	BspTraversalData tBackData(NULL, new PolygonContainer(), tData.mDepth + 1, mOutOfBoundsCell,
936	new BoundedRayContainer(), 0, 0, new BspNodeGeometry());
937
938	// create new interior node and two leaf nodes
939	BspInterior *interior =
940	SubdivideNode(tData, tFrontData, tBackData, coincident);
941
942
943	// extract view cells from coincident polygons according to plane normal
944	// only if front or back polygons are empty
945	if (!mGenerateViewCells)
946	{
947	ExtractViewCells(tFrontData,
948	tBackData,
949	coincident,
950	interior->mPlane);
951	}
952
953	// don't need coincident polygons anymory
954	CLEAR_CONTAINER(coincident);
955
956	// push the children on the stack
957	tStack.push(tFrontData);
958	tStack.push(tBackData);
959
960	// cleanup
961	DEL_PTR(tData.mNode);
962
963	DEL_PTR(tData.mPolygons);
964	DEL_PTR(tData.mRays);
965	DEL_PTR(tData.mGeometry);
966
967	return interior;
968	}
969
970	void BspTree::ExtractViewCells(BspTraversalData &frontData,
971	BspTraversalData &backData,
972	const PolygonContainer &coincident,
973	const Plane3 &splitPlane) const
974	{
975	// if not empty, tree is further subdivided => don't have to find view cell
976	bool foundFront = !frontData.mPolygons->empty();
977	bool foundBack = !frontData.mPolygons->empty();
978
979	PolygonContainer::const_iterator it =
980	coincident.begin(), it_end = coincident.end();
981
982	//-- find first view cells in front and back leafs
983	for (; !(foundFront && foundBack) && (it != it_end); ++ it)
984	{
985	if (DotProd((*it)->GetNormal(), splitPlane.mNormal) > 0)
986	{
987	backData.mViewCell = dynamic_cast<ViewCell >((it)->mParent);
988	foundBack = true;
989	}
990	else
991	{
992	frontData.mViewCell = dynamic_cast<ViewCell >((it)->mParent);
993	foundFront = true;
994	}
995	}
996	}
997
998	BspInterior *BspTree::SubdivideNode(BspTraversalData &tData,
999	BspTraversalData &frontData,
1000	BspTraversalData &backData,
1001	PolygonContainer &coincident)
1002	{
1003	mStat.nodes += 2;
1004
1005	BspLeaf leaf = dynamic_cast<BspLeaf >(tData.mNode);
1006
1007	long startTime;
1008	if (0)
1009	{
1010	Debug << "*********************" << endl;
1011	startTime = GetTime();
1012	}
1013
1014	// select subdivision plane
1015	BspInterior *interior =
1016	new BspInterior(SelectPlane(leaf, tData));
1017
1018	if (0)
1019	{
1020	Debug << "time used for split plane selection: "
1021	<< TimeDiff(startTime, GetTime()) * 1e-3 << "s" << endl;
1022	}
1023	#ifdef _DEBUG
1024	Debug << interior << endl;
1025	#endif
1026
1027
1028	if (0)
1029	{
1030	Debug << "number of rays: " << (int)tData.mRays->size() << endl;
1031	Debug << "number of polys: " << (int)tData.mPolygons->size() << endl;
1032
1033	startTime = GetTime();
1034	}
1035
1036	// subdivide rays into front and back rays
1037	SplitRays(interior->mPlane, tData.mRays, frontData.mRays, *backData.mRays);
1038
1039	if (0)
1040	{
1041	Debug << "time used for rays splitting: " << TimeDiff(startTime, GetTime())*1e-3 << "s" << endl;
1042	startTime = GetTime();
1043	}
1044
1045	// subdivide polygons with plane
1046	mStat.polySplits += SplitPolygons(interior->GetPlane(),
1047	*tData.mPolygons,
1048	*frontData.mPolygons,
1049	*backData.mPolygons,
1050	coincident);
1051
1052	if (0)
1053	{
1054	Debug << "time used for polygon splitting: " << TimeDiff(startTime, GetTime())*1e-3 << "s" << endl;
1055	}
1056
1057	// compute pvs
1058	frontData.mPvs = ComputePvsSize(*frontData.mRays);
1059	backData.mPvs = ComputePvsSize(*backData.mRays);
1060
1061	// split geometry and compute area
1062	if (1)
1063	{
1064	tData.mGeometry->SplitGeometry(*frontData.mGeometry,
1065	*backData.mGeometry,
1066	interior->mPlane,
1067	mBox,
1068	mEpsilon);
1069
1070
1071	frontData.mProbability = frontData.mGeometry->GetVolume();
1072	backData.mProbability = backData.mGeometry->GetVolume();
1073	}
1074
1075	// compute accumulated ray length
1076	//frontData.mAccRayLength = AccumulatedRayLength(*frontData.mRays);
1077	//backData.mAccRayLength = AccumulatedRayLength(*backData.mRays);
1078
1079	//-- create front and back leaf
1080
1081	BspInterior *parent = leaf->GetParent();
1082
1083	// replace a link from node's parent
1084	if (!leaf->IsRoot())
1085	{
1086	parent->ReplaceChildLink(leaf, interior);
1087	interior->SetParent(parent);
1088	}
1089	else // new root
1090	{
1091	mRoot = interior;
1092	}
1093
1094	// and setup child links
1095	interior->SetupChildLinks(new BspLeaf(interior), new BspLeaf(interior));
1096
1097	frontData.mNode = interior->GetFront();
1098	backData.mNode = interior->GetBack();
1099
1100	//DEL_PTR(leaf);
1101	return interior;
1102	}
1103
1104
1105	void BspTree::SortSplitCandidates(const PolygonContainer &polys,
1106	const int axis,
1107	vector<SortableEntry> &splitCandidates) const
1108	{
1109	splitCandidates.clear();
1110
1111	int requestedSize = 2 * (int)polys.size();
1112	// creates a sorted split candidates array
1113	splitCandidates.reserve(requestedSize);
1114
1115	PolygonContainer::const_iterator it, it_end = polys.end();
1116
1117	AxisAlignedBox3 box;
1118
1119	// insert all queries
1120	for(it = polys.begin(); it != it_end; ++ it)
1121	{
1122	box.Initialize();
1123	box.Include((it));
1124
1125	splitCandidates.push_back(SortableEntry(SortableEntry::POLY_MIN, box.Min(axis), *it));
1126	splitCandidates.push_back(SortableEntry(SortableEntry::POLY_MAX, box.Max(axis), *it));
1127	}
1128
1129	stable_sort(splitCandidates.begin(), splitCandidates.end());
1130	}
1131
1132
1133	float BspTree::BestCostRatio(const PolygonContainer &polys,
1134	const AxisAlignedBox3 &box,
1135	const int axis,
1136	float &position,
1137	int &objectsBack,
1138	int &objectsFront) const
1139	{
1140	vector<SortableEntry> splitCandidates;
1141
1142	SortSplitCandidates(polys, axis, splitCandidates);
1143
1144	// go through the lists, count the number of objects left and right
1145	// and evaluate the following cost funcion:
1146	// C = ct_div_ci + (ol + or)/queries
1147
1148	int objectsLeft = 0, objectsRight = (int)polys.size();
1149
1150	float minBox = box.Min(axis);
1151	float maxBox = box.Max(axis);
1152	float boxArea = box.SurfaceArea();
1153
1154	float minBand = minBox + mSplitBorder * (maxBox - minBox);
1155	float maxBand = minBox + (1.0f - mSplitBorder) * (maxBox - minBox);
1156
1157	float minSum = 1e20f;
1158	vector<SortableEntry>::const_iterator ci, ci_end = splitCandidates.end();
1159
1160	for(ci = splitCandidates.begin(); ci != ci_end; ++ ci)
1161	{
1162	switch ((*ci).type)
1163	{
1164	case SortableEntry::POLY_MIN:
1165	++ objectsLeft;
1166	break;
1167	case SortableEntry::POLY_MAX:
1168	-- objectsRight;
1169	break;
1170	default:
1171	break;
1172	}
1173
1174	if ((ci).value > minBand && (ci).value < maxBand)
1175	{
1176	AxisAlignedBox3 lbox = box;
1177	AxisAlignedBox3 rbox = box;
1178	lbox.SetMax(axis, (*ci).value);
1179	rbox.SetMin(axis, (*ci).value);
1180
1181	const float sum = objectsLeft * lbox.SurfaceArea() +
1182	objectsRight * rbox.SurfaceArea();
1183
1184	if (sum < minSum)
1185	{
1186	minSum = sum;
1187	position = (*ci).value;
1188
1189	objectsBack = objectsLeft;
1190	objectsFront = objectsRight;
1191	}
1192	}
1193	}
1194
1195	const float oldCost = (float)polys.size();
1196	const float newCost = mAxisAlignedCtDivCi + minSum / boxArea;
1197	const float ratio = newCost / oldCost;
1198
1199
1200	#if 0
1201	Debug << "====================" << endl;
1202	Debug << "costRatio=" << ratio << " pos=" << position<<" t=" << (position - minBox)/(maxBox - minBox)
1203	<< "\t o=(" << objectsBack << "," << objectsFront << ")" << endl;
1204	#endif
1205	return ratio;
1206	}
1207
1208	bool BspTree::SelectAxisAlignedPlane(Plane3 &plane,
1209	const PolygonContainer &polys) const
1210	{
1211	AxisAlignedBox3 box;
1212	box.Initialize();
1213
1214	// create bounding box of region
1215	Polygon3::IncludeInBox(polys, box);
1216
1217	int objectsBack = 0, objectsFront = 0;
1218	int axis = 0;
1219	float costRatio = MAX_FLOAT;
1220	Vector3 position;
1221
1222	//-- area subdivision
1223	for (int i = 0; i < 3; ++ i)
1224	{
1225	float p = 0;
1226	float r = BestCostRatio(polys, box, i, p, objectsBack, objectsFront);
1227
1228	if (r < costRatio)
1229	{
1230	costRatio = r;
1231	axis = i;
1232	position = p;
1233	}
1234	}
1235
1236	if (costRatio >= mMaxCostRatio)
1237	return false;
1238
1239	Vector3 norm(0,0,0); norm[axis] = 1.0f;
1240	plane = Plane3(norm, position);
1241
1242	return true;
1243	}
1244
1245
1246	Plane3 BspTree::SelectPlane(BspLeaf *leaf, BspTraversalData &data)
1247	{
1248	if (data.mPolygons->empty() && data.mRays->empty())
1249	{
1250	Debug << "Warning: No autopartition polygon candidate available\n";
1251
1252	// return axis aligned split
1253	AxisAlignedBox3 box;
1254	box.Initialize();
1255
1256	// create bounding box of region
1257	Polygon3::IncludeInBox(*data.mPolygons, box);
1258
1259	const int axis = box.Size().DrivingAxis();
1260	const Vector3 position = (box.Min()[axis] + box.Max()[axis]) * 0.5f;
1261
1262	Vector3 norm(0,0,0); norm[axis] = 1.0f;
1263	return Plane3(norm, position);
1264	}
1265
1266	if ((mSplitPlaneStrategy & AXIS_ALIGNED) &&
1267	((int)data.mPolygons->size() > mTermMinPolysForAxisAligned) &&
1268	((int)data.mRays->size() > mTermMinRaysForAxisAligned) &&
1269	((mTermMinObjectsForAxisAligned < 0) \|\|
1270	(Polygon3::ParentObjectsSize(*data.mPolygons) > mTermMinObjectsForAxisAligned)))
1271	{
1272	Plane3 plane;
1273	if (SelectAxisAlignedPlane(plane, *data.mPolygons))
1274	return plane;
1275	}
1276
1277	// simplest strategy: just take next polygon
1278	if (mSplitPlaneStrategy & RANDOM_POLYGON)
1279	{
1280	if (!data.mPolygons->empty())
1281	{
1282	Polygon3 *nextPoly =
1283	(*data.mPolygons)[(int)RandomValue(0, (Real)((int)data.mPolygons->size() - 1))];
1284	return nextPoly->GetSupportingPlane();
1285	}
1286	else
1287	{
1288	const int candidateIdx = (int)RandomValue(0, (Real)((int)data.mRays->size() - 1));
1289	BoundedRay bRay = (data.mRays)[candidateIdx];
1290
1291	Ray *ray = bRay->mRay;
1292
1293	const Vector3 minPt = ray->Extrap(bRay->mMinT);
1294	const Vector3 maxPt = ray->Extrap(bRay->mMaxT);
1295
1296	const Vector3 pt = (maxPt + minPt) * 0.5;
1297
1298	const Vector3 normal = ray->GetDir();
1299
1300	return Plane3(normal, pt);
1301	}
1302
1303	return Plane3();
1304	}
1305
1306	// use heuristics to find appropriate plane
1307	return SelectPlaneHeuristics(leaf, data);
1308	}
1309
1310
1311	Plane3 BspTree::ChooseCandidatePlane(const BoundedRayContainer &rays) const
1312	{
1313	const int candidateIdx = (int)RandomValue(0, (Real)((int)rays.size() - 1));
1314	BoundedRay *bRay = rays[candidateIdx];
1315	Ray *ray = bRay->mRay;
1316
1317	const Vector3 minPt = ray->Extrap(bRay->mMinT);
1318	const Vector3 maxPt = ray->Extrap(bRay->mMaxT);
1319
1320	const Vector3 pt = (maxPt + minPt) * 0.5;
1321
1322	const Vector3 normal = ray->GetDir();
1323
1324	return Plane3(normal, pt);
1325	}
1326
1327	Plane3 BspTree::ChooseCandidatePlane2(const BoundedRayContainer &rays) const
1328	{
1329	Vector3 pt[3];
1330	int idx[3];
1331	int cmaxT = 0;
1332	int cminT = 0;
1333	bool chooseMin = false;
1334
1335	for (int j = 0; j < 3; j ++)
1336	{
1337	idx[j] = (int)RandomValue(0, Real((int)rays.size() * 2 - 1));
1338
1339	if (idx[j] >= (int)rays.size())
1340	{
1341	idx[j] -= (int)rays.size();
1342	chooseMin = (cminT < 2);
1343	}
1344	else
1345	chooseMin = (cmaxT < 2);
1346
1347	BoundedRay *bRay = rays[idx[j]];
1348	pt[j] = chooseMin ? bRay->mRay->Extrap(bRay->mMinT) :
1349	bRay->mRay->Extrap(bRay->mMaxT);
1350	}
1351
1352	return Plane3(pt[0], pt[1], pt[2]);
1353	}
1354
1355	Plane3 BspTree::ChooseCandidatePlane3(const BoundedRayContainer &rays) const
1356	{
1357	Vector3 pt[3];
1358
1359	int idx1 = (int)RandomValue(0, (Real)((int)rays.size() - 1));
1360	int idx2 = (int)RandomValue(0, (Real)((int)rays.size() - 1));
1361
1362	// check if rays different
1363	if (idx1 == idx2)
1364	idx2 = (idx2 + 1) % (int)rays.size();
1365
1366	const BoundedRay *ray1 = rays[idx1];
1367	const BoundedRay *ray2 = rays[idx2];
1368
1369	// normal vector of the plane parallel to both lines
1370	const Vector3 norm =
1371	Normalize(CrossProd(ray1->mRay->GetDir(), ray2->mRay->GetDir()));
1372
1373	const Vector3 orig1 = ray1->mRay->Extrap(ray1->mMinT);
1374	const Vector3 orig2 = ray2->mRay->Extrap(ray2->mMinT);
1375
1376	// vector from line 1 to line 2
1377	const Vector3 vd = orig1 - orig2;
1378
1379	// project vector on normal to get distance
1380	const float dist = DotProd(vd, norm);
1381
1382	// point on plane lies halfway between the two planes
1383	const Vector3 planePt = orig1 + norm * dist * 0.5;
1384
1385	return Plane3(norm, planePt);
1386	}
1387
1388
1389	Plane3 BspTree::SelectPlaneHeuristics(BspLeaf *leaf, BspTraversalData &data)
1390	{
1391	float lowestCost = MAX_FLOAT;
1392	Plane3 bestPlane;
1393	// intermediate plane
1394	Plane3 plane;
1395
1396	const int limit = Min((int)data.mPolygons->size(), mMaxPolyCandidates);
1397	int maxIdx = (int)data.mPolygons->size();
1398
1399	for (int i = 0; i < limit; ++ i)
1400	{
1401	// assure that no index is taken twice
1402	const int candidateIdx = (int)RandomValue(0, (Real)(-- maxIdx));
1403
1404	Polygon3 poly = (data.mPolygons)[candidateIdx];
1405
1406	// swap candidate to the end to avoid testing same plane
1407	std::swap((data.mPolygons)[maxIdx], (data.mPolygons)[candidateIdx]);
1408	//Polygon3 poly = (data.mPolygons)[(int)RandomValue(0, (int)polys.size() - 1)];
1409
1410	// evaluate current candidate
1411	const float candidateCost =
1412	SplitPlaneCost(poly->GetSupportingPlane(), data);
1413
1414	if (candidateCost < lowestCost)
1415	{
1416	bestPlane = poly->GetSupportingPlane();
1417	lowestCost = candidateCost;
1418	}
1419	}
1420
1421	//-- choose candidate planes extracted from rays
1422	for (int i = 0; i < mMaxRayCandidates; ++ i)
1423	{
1424	plane = ChooseCandidatePlane3(*data.mRays);
1425	const float candidateCost = SplitPlaneCost(plane, data);
1426
1427	if (candidateCost < lowestCost)
1428	{
1429	bestPlane = plane;
1430	lowestCost = candidateCost;
1431	}
1432	}
1433
1434	#ifdef _DEBUG
1435	Debug << "plane lowest cost: " << lowestCost << endl;
1436	#endif
1437
1438	return bestPlane;
1439	}
1440
1441
1442	float BspTree::SplitPlaneCost(const Plane3 &candidatePlane,
1443	const PolygonContainer &polys) const
1444	{
1445	float val = 0;
1446
1447	float sumBalancedPolys = 0;
1448	float sumSplits = 0;
1449	float sumPolyArea = 0;
1450	float sumBalancedViewCells = 0;
1451	float sumBlockedRays = 0;
1452	float totalBlockedRays = 0;
1453	//float totalArea = 0;
1454	int totalViewCells = 0;
1455
1456	// need three unique ids for each type of view cell
1457	// for balanced view cells criterium
1458	ViewCell::NewMail();
1459	const int backId = ViewCell::sMailId;
1460	ViewCell::NewMail();
1461	const int frontId = ViewCell::sMailId;
1462	ViewCell::NewMail();
1463	const int frontAndBackId = ViewCell::sMailId;
1464
1465	bool useRand;;
1466	int limit;
1467
1468	// choose test polyongs randomly if over threshold
1469	if ((int)polys.size() > mMaxTests)
1470	{
1471	useRand = true;
1472	limit = mMaxTests;
1473	}
1474	else
1475	{
1476	useRand = false;
1477	limit = (int)polys.size();
1478	}
1479
1480	for (int i = 0; i < limit; ++ i)
1481	{
1482	const int testIdx = useRand ? (int)RandomValue(0, (Real)(limit - 1)) : i;
1483
1484	Polygon3 *poly = polys[testIdx];
1485
1486	const int classification =
1487	poly->ClassifyPlane(candidatePlane, mEpsilon);
1488
1489	if (mSplitPlaneStrategy & BALANCED_POLYS)
1490	sumBalancedPolys += sBalancedPolysTable[classification];
1491
1492	if (mSplitPlaneStrategy & LEAST_SPLITS)
1493	sumSplits += sLeastPolySplitsTable[classification];
1494
1495	if (mSplitPlaneStrategy & LARGEST_POLY_AREA)
1496	{
1497	if (classification == Polygon3::COINCIDENT)
1498	sumPolyArea += poly->GetArea();
1499	//totalArea += area;
1500	}
1501
1502	if (mSplitPlaneStrategy & BLOCKED_RAYS)
1503	{
1504	const float blockedRays = (float)poly->mPiercingRays.size();
1505
1506	if (classification == Polygon3::COINCIDENT)
1507	sumBlockedRays += blockedRays;
1508
1509	totalBlockedRays += blockedRays;
1510	}
1511
1512	// assign view cells to back or front according to classificaion
1513	if (mSplitPlaneStrategy & BALANCED_VIEW_CELLS)
1514	{
1515	MeshInstance *viewCell = poly->mParent;
1516
1517	// assure that we only count a view cell
1518	// once for the front and once for the back side of the plane
1519	if (classification == Polygon3::FRONT_SIDE)
1520	{
1521	if ((viewCell->mMailbox != frontId) &&
1522	(viewCell->mMailbox != frontAndBackId))
1523	{
1524	sumBalancedViewCells += 1.0;
1525
1526	if (viewCell->mMailbox != backId)
1527	viewCell->mMailbox = frontId;
1528	else
1529	viewCell->mMailbox = frontAndBackId;
1530
1531	++ totalViewCells;
1532	}
1533	}
1534	else if (classification == Polygon3::BACK_SIDE)
1535	{
1536	if ((viewCell->mMailbox != backId) &&
1537	(viewCell->mMailbox != frontAndBackId))
1538	{
1539	sumBalancedViewCells -= 1.0;
1540
1541	if (viewCell->mMailbox != frontId)
1542	viewCell->mMailbox = backId;
1543	else
1544	viewCell->mMailbox = frontAndBackId;
1545
1546	++ totalViewCells;
1547	}
1548	}
1549	}
1550	}
1551
1552	const float polysSize = (float)polys.size() + Limits::Small;
1553
1554	// all values should be approx. between 0 and 1 so they can be combined
1555	// and scaled with the factors according to their importance
1556	if (mSplitPlaneStrategy & BALANCED_POLYS)
1557	val += mBalancedPolysFactor * fabs(sumBalancedPolys) / polysSize;
1558
1559	if (mSplitPlaneStrategy & LEAST_SPLITS)
1560	val += mLeastSplitsFactor * sumSplits / polysSize;
1561
1562	if (mSplitPlaneStrategy & LARGEST_POLY_AREA)
1563	// HACK: polys.size should be total area so scaling is between 0 and 1
1564	val += mLargestPolyAreaFactor * (float)polys.size() / sumPolyArea;
1565
1566	if (mSplitPlaneStrategy & BLOCKED_RAYS)
1567	if (totalBlockedRays != 0)
1568	val += mBlockedRaysFactor * (totalBlockedRays - sumBlockedRays) / totalBlockedRays;
1569
1570	if (mSplitPlaneStrategy & BALANCED_VIEW_CELLS)
1571	val += mBalancedViewCellsFactor * fabs(sumBalancedViewCells) /
1572	((float)totalViewCells + Limits::Small);
1573
1574	return val;
1575	}
1576
1577
1578	inline void BspTree::GenerateUniqueIdsForPvs()
1579	{
1580	Intersectable::NewMail(); sBackId = ViewCell::sMailId;
1581	Intersectable::NewMail(); sFrontId = ViewCell::sMailId;
1582	Intersectable::NewMail(); sFrontAndBackId = ViewCell::sMailId;
1583	}
1584
1585
1586	float BspTree::SplitPlaneCost(const Plane3 &candidatePlane,
1587	const BoundedRayContainer &rays,
1588	const int pvs,
1589	const float probability,
1590	const BspNodeGeometry &cell) const
1591	{
1592	float val = 0;
1593
1594	float sumBalancedRays = 0;
1595	float sumRaySplits = 0;
1596
1597	int frontPvs = 0;
1598	int backPvs = 0;
1599
1600	// probability that view point lies in child
1601	float pOverall = 0;
1602	float pFront = 0;
1603	float pBack = 0;
1604
1605	const bool pvsUseLen = false;
1606
1607	if (mSplitPlaneStrategy & PVS)
1608	{
1609	// create unique ids for pvs heuristics
1610	GenerateUniqueIdsForPvs();
1611
1612	// construct child geometry with regard to the candidate split plane
1613	BspNodeGeometry frontCell;
1614	BspNodeGeometry backCell;
1615
1616	cell.SplitGeometry(frontCell,
1617	backCell,
1618	candidatePlane,
1619	mBox,
1620	mEpsilon);
1621
1622	if (mUseAreaForPvs)
1623	{
1624	pFront = frontCell.GetArea();
1625	pBack = backCell.GetArea();
1626	}
1627	else
1628	{
1629	pFront = frontCell.GetVolume();
1630	pBack = pOverall - pFront;
1631	}
1632
1633
1634	pOverall = probability;
1635	}
1636
1637	bool useRand;
1638	int limit;
1639
1640	// choose test polyongs randomly if over threshold
1641	if ((int)rays.size() > mMaxTests)
1642	{
1643	useRand = true;
1644	limit = mMaxTests;
1645	}
1646	else
1647	{
1648	useRand = false;
1649	limit = (int)rays.size();
1650	}
1651
1652	for (int i = 0; i < limit; ++ i)
1653	{
1654	const int testIdx = useRand ? (int)RandomValue(0, (Real)(limit - 1)) : i;
1655
1656	BoundedRay *bRay = rays[testIdx];
1657
1658	Ray *ray = bRay->mRay;
1659	const float minT = bRay->mMinT;
1660	const float maxT = bRay->mMaxT;
1661
1662	Vector3 entP, extP;
1663
1664	const int cf =
1665	ray->ClassifyPlane(candidatePlane, minT, maxT, entP, extP);
1666
1667	if (mSplitPlaneStrategy & LEAST_RAY_SPLITS)
1668	{
1669	sumBalancedRays += sBalancedRaysTable[cf];
1670	}
1671
1672	if (mSplitPlaneStrategy & BALANCED_RAYS)
1673	{
1674	sumRaySplits += sLeastRaySplitsTable[cf];
1675	}
1676
1677	if (mSplitPlaneStrategy & PVS)
1678	{
1679	// in case the ray intersects an object
1680	// assure that we only count the object
1681	// once for the front and once for the back side of the plane
1682
1683	// add the termination object
1684	if (!ray->intersections.empty())
1685	AddObjToPvs(ray->intersections[0].mObject, cf, frontPvs, backPvs);
1686
1687	// add the source object
1688	AddObjToPvs(ray->sourceObject.mObject, cf, frontPvs, backPvs);
1689	}
1690	}
1691
1692	const float raysSize = (float)rays.size() + Limits::Small;
1693
1694	if (mSplitPlaneStrategy & LEAST_RAY_SPLITS)
1695	val += mLeastRaySplitsFactor * sumRaySplits / raysSize;
1696
1697	if (mSplitPlaneStrategy & BALANCED_RAYS)
1698	val += mBalancedRaysFactor * fabs(sumBalancedRays) / raysSize;
1699
1700	const float denom = pOverall * (float)pvs * 2.0f + Limits::Small;
1701
1702	if (mSplitPlaneStrategy & PVS)
1703	{
1704	val += mPvsFactor * (frontPvs * pFront + (backPvs * pBack)) / denom;
1705
1706	// give penalty to unbalanced split
1707	if (0)
1708	if (((pFront * 0.2 + Limits::Small) > pBack) \|\|
1709	(pFront < (pBack * 0.2 + Limits::Small)))
1710	val += 0.5;
1711	}
1712
1713
1714	#ifdef _DEBUG
1715	Debug << "totalpvs: " << pvs << " ptotal: " << pOverall
1716	<< " frontpvs: " << frontPvs << " pFront: " << pFront
1717	<< " backpvs: " << backPvs << " pBack: " << pBack << endl << endl;
1718	#endif
1719
1720	return val;
1721	}
1722
1723	void BspTree::AddObjToPvs(Intersectable *obj,
1724	const int cf,
1725	int &frontPvs,
1726	int &backPvs) const
1727	{
1728	if (!obj)
1729	return;
1730	// TODO: does this really belong to no pvs?
1731	//if (cf == Ray::COINCIDENT) return;
1732
1733	// object belongs to both PVS
1734	const bool bothSides = (cf == Ray::FRONT_BACK) \|\|
1735	(cf == Ray::BACK_FRONT) \|\|
1736	(cf == Ray::COINCIDENT);
1737
1738	if ((cf == Ray::FRONT) \|\| bothSides)
1739	{
1740	if ((obj->mMailbox != sFrontId) &&
1741	(obj->mMailbox != sFrontAndBackId))
1742	{
1743	++ frontPvs;
1744
1745	if (obj->mMailbox == sBackId)
1746	obj->mMailbox = sFrontAndBackId;
1747	else
1748	obj->mMailbox = sFrontId;
1749	}
1750	}
1751
1752	if ((cf == Ray::BACK) \|\| bothSides)
1753	{
1754	if ((obj->mMailbox != sBackId) &&
1755	(obj->mMailbox != sFrontAndBackId))
1756	{
1757	++ backPvs;
1758
1759	if (obj->mMailbox == sFrontId)
1760	obj->mMailbox = sFrontAndBackId;
1761	else
1762	obj->mMailbox = sBackId;
1763	}
1764	}
1765	}
1766
1767	float BspTree::SplitPlaneCost(const Plane3 &candidatePlane,
1768	BspTraversalData &data) const
1769	{
1770	float val = 0;
1771
1772	if (mSplitPlaneStrategy & VERTICAL_AXIS)
1773	{
1774	Vector3 tinyAxis(0,0,0); tinyAxis[mBox.Size().TinyAxis()] = 1.0f;
1775	// we put a penalty on the dot product between the "tiny" vertical axis
1776	// and the split plane axis
1777	val += mVerticalSplitsFactor *
1778	fabs(DotProd(candidatePlane.mNormal, tinyAxis));
1779	}
1780
1781	// the following criteria loop over all polygons to find the cost value
1782	if ((mSplitPlaneStrategy & BALANCED_POLYS) \|\|
1783	(mSplitPlaneStrategy & LEAST_SPLITS) \|\|
1784	(mSplitPlaneStrategy & LARGEST_POLY_AREA) \|\|
1785	(mSplitPlaneStrategy & BALANCED_VIEW_CELLS) \|\|
1786	(mSplitPlaneStrategy & BLOCKED_RAYS))
1787	{
1788	val += SplitPlaneCost(candidatePlane, *data.mPolygons);
1789	}
1790
1791	// the following criteria loop over all rays to find the cost value
1792	if ((mSplitPlaneStrategy & BALANCED_RAYS) \|\|
1793	(mSplitPlaneStrategy & LEAST_RAY_SPLITS) \|\|
1794	(mSplitPlaneStrategy & PVS))
1795	{
1796	val += SplitPlaneCost(candidatePlane, *data.mRays, data.mPvs,
1797	data.mProbability, *data.mGeometry);
1798	}
1799
1800	// return linear combination of the sums
1801	return val;
1802	}
1803
1804	void BspTree::CollectLeaves(vector<BspLeaf *> &leaves) const
1805	{
1806	stack<BspNode *> nodeStack;
1807	nodeStack.push(mRoot);
1808
1809	while (!nodeStack.empty())
1810	{
1811	BspNode *node = nodeStack.top();
1812
1813	nodeStack.pop();
1814
1815	if (node->IsLeaf())
1816	{
1817	BspLeaf leaf = (BspLeaf )node;
1818	leaves.push_back(leaf);
1819	}
1820	else
1821	{
1822	BspInterior interior = dynamic_cast<BspInterior >(node);
1823
1824	nodeStack.push(interior->GetBack());
1825	nodeStack.push(interior->GetFront());
1826	}
1827	}
1828	}
1829
1830
1831	AxisAlignedBox3 BspTree::GetBoundingBox() const
1832	{
1833	return mBox;
1834	}
1835
1836
1837	void BspTree::EvaluateLeafStats(const BspTraversalData &data)
1838	{
1839	// the node became a leaf -> evaluate stats for leafs
1840	BspLeaf leaf = dynamic_cast<BspLeaf >(data.mNode);
1841
1842	// store maximal and minimal depth
1843	if (data.mDepth > mStat.maxDepth)
1844	mStat.maxDepth = data.mDepth;
1845
1846	if (data.mDepth < mStat.minDepth)
1847	mStat.minDepth = data.mDepth;
1848
1849	// accumulate depth to compute average depth
1850	mStat.accumDepth += data.mDepth;
1851	// accumulate rays to compute rays / leaf
1852	mStat.accumRays += (int)data.mRays->size();
1853
1854	if (data.mDepth >= mTermMaxDepth)
1855	++ mStat.maxDepthNodes;
1856
1857	if (data.mPvs < mTermMinPvs)
1858	++ mStat.minPvsNodes;
1859
1860	if ((int)data.mRays->size() < mTermMinRays)
1861	++ mStat.minRaysNodes;
1862
1863	if (data.GetAvgRayContribution() > mTermMaxRayContribution)
1864	++ mStat.maxRayContribNodes;
1865
1866	if (data.mProbability <= mTermMinProbability)
1867	++ mStat.minProbabilityNodes;
1868
1869	#ifdef _DEBUG
1870	Debug << "BSP stats: "
1871	<< "Depth: " << data.mDepth << " (max: " << mTermMaxDepth << "), "
1872	<< "PVS: " << data.mPvs << " (min: " << mTermMinPvs << "), "
1873	<< "Probability: " << data.mProbability << " (min: " << mTermMinProbability << "), "
1874	<< "#polygons: " << (int)data.mPolygons->size() << " (max: " << mTermMinPolys << "), "
1875	<< "#rays: " << (int)data.mRays->size() << " (max: " << mTermMinRays << "), "
1876	<< "#pvs: " << leaf->GetViewCell()->GetPvs().GetSize() << "=, "
1877	<< "#avg ray contrib (pvs): " << (float)data.mPvs / (float)data.mRays->size() << endl;
1878	#endif
1879	}
1880
1881	int
1882	BspTree::_CastRay(Ray &ray)
1883	{
1884	int hits = 0;
1885
1886	stack<BspRayTraversalData> tStack;
1887
1888	float maxt, mint;
1889
1890	if (!mBox.GetRaySegment(ray, mint, maxt))
1891	return 0;
1892
1893	Intersectable::NewMail();
1894
1895	Vector3 entp = ray.Extrap(mint);
1896	Vector3 extp = ray.Extrap(maxt);
1897
1898	BspNode *node = mRoot;
1899	BspNode *farChild = NULL;
1900
1901	while (1)
1902	{
1903	if (!node->IsLeaf())
1904	{
1905	BspInterior in = dynamic_cast<BspInterior >(node);
1906
1907	Plane3 splitPlane = in->GetPlane();
1908	const int entSide = splitPlane.Side(entp);
1909	const int extSide = splitPlane.Side(extp);
1910
1911	if (entSide < 0)
1912	{
1913	node = in->GetBack();
1914
1915	if(extSide <= 0) // plane does not split ray => no far child
1916	continue;
1917
1918	farChild = in->GetFront(); // plane splits ray
1919
1920	} else if (entSide > 0)
1921	{
1922	node = in->GetFront();
1923
1924	if (extSide >= 0) // plane does not split ray => no far child
1925	continue;
1926
1927	farChild = in->GetBack(); // plane splits ray
1928	}
1929	else // ray and plane are coincident
1930	{
1931	// WHAT TO DO IN THIS CASE ?
1932	//break;
1933	node = in->GetFront();
1934	continue;
1935	}
1936
1937	// push data for far child
1938	tStack.push(BspRayTraversalData(farChild, extp, maxt));
1939
1940	// find intersection of ray segment with plane
1941	float t;
1942	extp = splitPlane.FindIntersection(ray.GetLoc(), extp, &t);
1943	maxt *= t;
1944
1945	} else // reached leaf => intersection with view cell
1946	{
1947	BspLeaf leaf = dynamic_cast<BspLeaf >(node);
1948
1949	if (!leaf->mViewCell->Mailed())
1950	{
1951	// ray.bspIntersections.push_back(Ray::BspIntersection(maxt, leaf));
1952	leaf->mViewCell->Mail();
1953	++ hits;
1954	}
1955
1956	//-- fetch the next far child from the stack
1957	if (tStack.empty())
1958	break;
1959
1960	entp = extp;
1961	mint = maxt; // NOTE: need this?
1962
1963	if (ray.GetType() == Ray::LINE_SEGMENT && mint > 1.0f)
1964	break;
1965
1966	BspRayTraversalData &s = tStack.top();
1967
1968	node = s.mNode;
1969	extp = s.mExitPoint;
1970	maxt = s.mMaxT;
1971
1972	tStack.pop();
1973	}
1974	}
1975
1976	return hits;
1977	}
1978
1979
1980	int BspTree::CastLineSegment(const Vector3 &origin,
1981	const Vector3 &termination,
1982	vector<ViewCell *> &viewcells)
1983	{
1984	int hits = 0;
1985	stack<BspRayTraversalData> tStack;
1986
1987	float mint = 0.0f, maxt = 1.0f;
1988
1989	Intersectable::NewMail();
1990	ViewCell::NewMail();
1991
1992	Vector3 entp = origin;
1993	Vector3 extp = termination;
1994
1995	BspNode *node = mRoot;
1996	BspNode *farChild = NULL;
1997
1998	while (1)
1999	{
2000	if (!node->IsLeaf())
2001	{
2002	BspInterior in = dynamic_cast<BspInterior >(node);
2003
2004	Plane3 splitPlane = in->GetPlane();
2005
2006	const int entSide = splitPlane.Side(entp);
2007	const int extSide = splitPlane.Side(extp);
2008
2009	if (entSide < 0)
2010	{
2011	node = in->GetBack();
2012
2013	if(extSide <= 0) // plane does not split ray => no far child
2014	continue;
2015
2016	farChild = in->GetFront(); // plane splits ray
2017
2018	}
2019	else if (entSide > 0)
2020	{
2021	node = in->GetFront();
2022
2023	if (extSide >= 0) // plane does not split ray => no far child
2024	continue;
2025
2026	farChild = in->GetBack(); // plane splits ray
2027	}
2028	else // ray and plane are coincident
2029	{
2030	// WHAT TO DO IN THIS CASE ?
2031	//break;
2032	node = in->GetFront();
2033	continue;
2034	}
2035
2036	// push data for far child
2037	tStack.push(BspRayTraversalData(farChild, extp, maxt));
2038
2039	// find intersection of ray segment with plane
2040	float t;
2041	extp = splitPlane.FindIntersection(origin, extp, &t);
2042	maxt *= t;
2043	}
2044	else
2045	{
2046	// reached leaf => intersection with view cell
2047	BspLeaf leaf = dynamic_cast<BspLeaf >(node);
2048
2049	if (!leaf->mViewCell->Mailed())
2050	{
2051	viewcells.push_back(leaf->mViewCell);
2052	leaf->mViewCell->Mail();
2053	hits++;
2054	}
2055
2056	//-- fetch the next far child from the stack
2057	if (tStack.empty())
2058	break;
2059
2060	entp = extp;
2061	mint = maxt; // NOTE: need this?
2062
2063	BspRayTraversalData &s = tStack.top();
2064
2065	node = s.mNode;
2066	extp = s.mExitPoint;
2067	maxt = s.mMaxT;
2068
2069	tStack.pop();
2070	}
2071	}
2072	return hits;
2073	}
2074
2075
2076	void BspTree::CollectViewCells(ViewCellContainer &viewCells) const
2077	{
2078	stack<BspNode *> nodeStack;
2079	nodeStack.push(mRoot);
2080
2081	ViewCell::NewMail();
2082
2083	while (!nodeStack.empty())
2084	{
2085	BspNode *node = nodeStack.top();
2086	nodeStack.pop();
2087
2088	if (node->IsLeaf())
2089	{
2090	ViewCell viewCell = dynamic_cast<BspLeaf >(node)->mViewCell;
2091
2092	if (!viewCell->Mailed())
2093	{
2094	viewCell->Mail();
2095	viewCells.push_back(viewCell);
2096	}
2097	}
2098	else
2099	{
2100	BspInterior interior = dynamic_cast<BspInterior >(node);
2101
2102	nodeStack.push(interior->GetFront());
2103	nodeStack.push(interior->GetBack());
2104	}
2105	}
2106	}
2107
2108
2109	BspTreeStatistics &BspTree::GetStat()
2110	{
2111	return mStat;
2112	}
2113
2114
2115	float BspTree::AccumulatedRayLength(BoundedRayContainer &rays) const
2116	{
2117	float len = 0;
2118
2119	BoundedRayContainer::const_iterator it, it_end = rays.end();
2120
2121	for (it = rays.begin(); it != it_end; ++ it)
2122	{
2123	len += SqrDistance((it)->mRay->Extrap((it)->mMinT),
2124	(it)->mRay->Extrap((it)->mMaxT));
2125	}
2126
2127	return len;
2128	}
2129
2130
2131	int BspTree::SplitRays(const Plane3 &plane,
2132	BoundedRayContainer &rays,
2133	BoundedRayContainer &frontRays,
2134	BoundedRayContainer &backRays)
2135	{
2136	int splits = 0;
2137
2138	while (!rays.empty())
2139	{
2140	BoundedRay *bRay = rays.back();
2141	Ray *ray = bRay->mRay;
2142	float minT = bRay->mMinT;
2143	float maxT = bRay->mMaxT;
2144
2145	rays.pop_back();
2146
2147	Vector3 entP, extP;
2148
2149	const int cf =
2150	ray->ClassifyPlane(plane, minT, maxT, entP, extP);
2151
2152	// set id to ray classification
2153	ray->SetId(cf);
2154
2155	switch (cf)
2156	{
2157	case Ray::COINCIDENT: // TODO: should really discard ray?
2158	frontRays.push_back(bRay);
2159	//DEL_PTR(bRay);
2160	break;
2161	case Ray::BACK:
2162	backRays.push_back(bRay);
2163	break;
2164	case Ray::FRONT:
2165	frontRays.push_back(bRay);
2166	break;
2167	case Ray::FRONT_BACK:
2168	{
2169	// find intersection of ray segment with plane
2170	const float t = plane.FindT(ray->GetLoc(), extP);
2171
2172	const float newT = t * maxT;
2173
2174	frontRays.push_back(new BoundedRay(ray, minT, newT));
2175	backRays.push_back(new BoundedRay(ray, newT, maxT));
2176
2177	DEL_PTR(bRay);
2178	}
2179	break;
2180	case Ray::BACK_FRONT:
2181	{
2182	// find intersection of ray segment with plane
2183	const float t = plane.FindT(ray->GetLoc(), extP);
2184	const float newT = t * bRay->mMaxT;
2185
2186	backRays.push_back(new BoundedRay(ray, minT, newT));
2187	frontRays.push_back(new BoundedRay(ray, newT, maxT));
2188
2189	DEL_PTR(bRay);
2190
2191	++ splits;
2192	}
2193	break;
2194	default:
2195	Debug << "Should not come here 4" << endl;
2196	break;
2197	}
2198	}
2199
2200	return splits;
2201	}
2202
2203	void BspTree::ExtractHalfSpaces(BspNode *n, vector<Plane3> &halfSpaces) const
2204	{
2205	BspNode *lastNode;
2206	do
2207	{
2208	lastNode = n;
2209
2210	// want to get planes defining geometry of this node => don't take
2211	// split plane of node itself
2212	n = n->GetParent();
2213
2214	if (n)
2215	{
2216	BspInterior interior = dynamic_cast<BspInterior >(n);
2217	Plane3 halfSpace = dynamic_cast<BspInterior *>(interior)->GetPlane();
2218
2219	if (interior->GetFront() != lastNode)
2220	halfSpace.ReverseOrientation();
2221
2222	halfSpaces.push_back(halfSpace);
2223	}
2224	}
2225	while (n);
2226	}
2227
2228
2229
2230	void BspTree::ConstructGeometry(ViewCell *vc,
2231	BspNodeGeometry &vcGeom) const
2232	{
2233	ViewCellContainer leaves;
2234	mViewCellsTree->CollectLeaves(vc, leaves);
2235
2236	ViewCellContainer::const_iterator it, it_end = leaves.end();
2237
2238	for (it = leaves.begin(); it != it_end; ++ it)
2239	{
2240	BspLeaf l = dynamic_cast<BspViewCell >(*it)->mLeaf;
2241	ConstructGeometry(l, vcGeom);
2242	}
2243	}
2244
2245
2246	void BspTree::SetViewCellsManager(ViewCellsManager *vcm)
2247	{
2248	mViewCellsManager = vcm;
2249	}
2250
2251
2252	void BspTree::ConstructGeometry(BspNode *n, BspNodeGeometry &geom) const
2253	{
2254	vector<Plane3> halfSpaces;
2255	ExtractHalfSpaces(n, halfSpaces);
2256
2257	PolygonContainer candidates;
2258
2259	// bounded planes are added to the polygons (reverse polygons
2260	// as they have to be outfacing
2261	for (int i = 0; i < (int)halfSpaces.size(); ++ i)
2262	{
2263	Polygon3 *p = GetBoundingBox().CrossSection(halfSpaces[i]);
2264
2265	if (p->Valid(mEpsilon))
2266	{
2267	candidates.push_back(p->CreateReversePolygon());
2268	DEL_PTR(p);
2269	}
2270	}
2271
2272	// add faces of bounding box (also could be faces of the cell)
2273	for (int i = 0; i < 6; ++ i)
2274	{
2275	VertexContainer vertices;
2276
2277	for (int j = 0; j < 4; ++ j)
2278	vertices.push_back(mBox.GetFace(i).mVertices[j]);
2279
2280	candidates.push_back(new Polygon3(vertices));
2281	}
2282
2283	for (int i = 0; i < (int)candidates.size(); ++ i)
2284	{
2285	// polygon is split by all other planes
2286	for (int j = 0; (j < (int)halfSpaces.size()) && candidates[i]; ++ j)
2287	{
2288	if (i == j) // polygon and plane are coincident
2289	continue;
2290
2291	VertexContainer splitPts;
2292	Polygon3 frontPoly, backPoly;
2293
2294	const int cf = candidates[i]->
2295	ClassifyPlane(halfSpaces[j], mEpsilon);
2296
2297	switch (cf)
2298	{
2299	case Polygon3::SPLIT:
2300	frontPoly = new Polygon3();
2301	backPoly = new Polygon3();
2302
2303	candidates[i]->Split(halfSpaces[j],
2304	*frontPoly,
2305	*backPoly,
2306	mEpsilon);
2307
2308	DEL_PTR(candidates[i]);
2309
2310	if (frontPoly->Valid(mEpsilon))
2311	candidates[i] = frontPoly;
2312	else
2313	DEL_PTR(frontPoly);
2314
2315	DEL_PTR(backPoly);
2316	break;
2317	case Polygon3::BACK_SIDE:
2318	DEL_PTR(candidates[i]);
2319	break;
2320	// just take polygon as it is
2321	case Polygon3::FRONT_SIDE:
2322	case Polygon3::COINCIDENT:
2323	default:
2324	break;
2325	}
2326	}
2327
2328	if (candidates[i])
2329	geom.mPolys.push_back(candidates[i]);
2330	}
2331	}
2332
2333
2334	typedef pair<BspNode , BspNodeGeometry > bspNodePair;
2335
2336
2337	int BspTree::FindNeighbors(BspNode n, vector<BspLeaf > &neighbors,
2338	const bool onlyUnmailed) const
2339	{
2340	stack<bspNodePair> nodeStack;
2341
2342	BspNodeGeometry nodeGeom;
2343	ConstructGeometry(n, nodeGeom);
2344
2345	// split planes from the root to this node
2346	// needed to verify that we found neighbor leaf
2347	// TODO: really needed?
2348	vector<Plane3> halfSpaces;
2349	ExtractHalfSpaces(n, halfSpaces);
2350
2351
2352	BspNodeGeometry *rgeom = new BspNodeGeometry();
2353	ConstructGeometry(mRoot, *rgeom);
2354
2355	nodeStack.push(bspNodePair(mRoot, rgeom));
2356
2357	while (!nodeStack.empty())
2358	{
2359	BspNode *node = nodeStack.top().first;
2360	BspNodeGeometry *geom = nodeStack.top().second;
2361
2362	nodeStack.pop();
2363
2364	if (node->IsLeaf())
2365	{
2366	// test if this leaf is in valid view space
2367	if (node->TreeValid() &&
2368	(node != n) &&
2369	(!onlyUnmailed \|\| !node->Mailed()))
2370	{
2371	bool isAdjacent = true;
2372
2373	if (1)
2374	{
2375	// test all planes of current node if still adjacent
2376	for (int i = 0; (i < halfSpaces.size()) && isAdjacent; ++ i)
2377	{
2378	const int cf =
2379	Polygon3::ClassifyPlane(geom->mPolys,
2380	halfSpaces[i],
2381	mEpsilon);
2382
2383	if (cf == Polygon3::BACK_SIDE)
2384	{
2385	isAdjacent = false;
2386	}
2387	}
2388	}
2389	else
2390	{
2391	// TODO: why is this wrong??
2392	// test all planes of current node if still adjacent
2393	for (int i = 0; (i < (int)nodeGeom.mPolys.size()) && isAdjacent; ++ i)
2394	{
2395	Polygon3 *poly = nodeGeom.mPolys[i];
2396
2397	const int cf =
2398	Polygon3::ClassifyPlane(geom->mPolys,
2399	poly->GetSupportingPlane(),
2400	mEpsilon);
2401
2402	if (cf == Polygon3::BACK_SIDE)
2403	{
2404	isAdjacent = false;
2405	}
2406	}
2407	}
2408	// neighbor was found
2409	if (isAdjacent)
2410	{
2411	neighbors.push_back(dynamic_cast<BspLeaf *>(node));
2412	}
2413	}
2414	}
2415	else
2416	{
2417	BspInterior interior = dynamic_cast<BspInterior >(node);
2418
2419	const int cf = Polygon3::ClassifyPlane(nodeGeom.mPolys,
2420	interior->GetPlane(),
2421	mEpsilon);
2422
2423	BspNode *front = interior->GetFront();
2424	BspNode *back = interior->GetBack();
2425
2426	BspNodeGeometry *fGeom = new BspNodeGeometry();
2427	BspNodeGeometry *bGeom = new BspNodeGeometry();
2428
2429	geom->SplitGeometry(*fGeom,
2430	*bGeom,
2431	interior->GetPlane(),
2432	mBox,
2433	mEpsilon);
2434
2435	if (cf == Polygon3::FRONT_SIDE)
2436	{
2437	nodeStack.push(bspNodePair(interior->GetFront(), fGeom));
2438	DEL_PTR(bGeom);
2439	}
2440	else
2441	{
2442	if (cf == Polygon3::BACK_SIDE)
2443	{
2444	nodeStack.push(bspNodePair(interior->GetBack(), bGeom));
2445	DEL_PTR(fGeom);
2446	}
2447	else
2448	{ // random decision
2449	nodeStack.push(bspNodePair(front, fGeom));
2450	nodeStack.push(bspNodePair(back, bGeom));
2451	}
2452	}
2453	}
2454
2455	DEL_PTR(geom);
2456	}
2457
2458	return (int)neighbors.size();
2459	}
2460
2461
2462	BspLeaf *BspTree::GetRandomLeaf(const Plane3 &halfspace)
2463	{
2464	stack<BspNode *> nodeStack;
2465	nodeStack.push(mRoot);
2466
2467	int mask = rand();
2468
2469	while (!nodeStack.empty())
2470	{
2471	BspNode *node = nodeStack.top();
2472	nodeStack.pop();
2473
2474	if (node->IsLeaf())
2475	{
2476	return dynamic_cast<BspLeaf *>(node);
2477	}
2478	else
2479	{
2480	BspInterior interior = dynamic_cast<BspInterior >(node);
2481	BspNode *next;
2482
2483	BspNodeGeometry geom;
2484	// todo: not very efficient: constructs full cell everytime
2485	ConstructGeometry(interior, geom);
2486
2487	const int cf = Polygon3::ClassifyPlane(geom.mPolys,
2488	halfspace,
2489	mEpsilon);
2490
2491	if (cf == Polygon3::BACK_SIDE)
2492	next = interior->GetFront();
2493	else
2494	if (cf == Polygon3::FRONT_SIDE)
2495	next = interior->GetFront();
2496	else
2497	{
2498	// random decision
2499	if (mask & 1)
2500	next = interior->GetBack();
2501	else
2502	next = interior->GetFront();
2503	mask = mask >> 1;
2504	}
2505
2506	nodeStack.push(next);
2507	}
2508	}
2509
2510	return NULL;
2511	}
2512
2513
2514	BspLeaf *BspTree::GetRandomLeaf(const bool onlyUnmailed)
2515	{
2516	stack<BspNode *> nodeStack;
2517
2518	nodeStack.push(mRoot);
2519
2520	int mask = rand();
2521
2522	while (!nodeStack.empty())
2523	{
2524	BspNode *node = nodeStack.top();
2525	nodeStack.pop();
2526
2527	if (node->IsLeaf())
2528	{
2529	if ( (!onlyUnmailed \|\| !node->Mailed()) )
2530	return dynamic_cast<BspLeaf *>(node);
2531	}
2532	else
2533	{
2534	BspInterior interior = dynamic_cast<BspInterior >(node);
2535
2536	// random decision
2537	if (mask & 1)
2538	nodeStack.push(interior->GetBack());
2539	else
2540	nodeStack.push(interior->GetFront());
2541
2542	mask = mask >> 1;
2543	}
2544	}
2545
2546	return NULL;
2547	}
2548
2549
2550	void BspTree::AddToPvs(BspLeaf *leaf,
2551	const BoundedRayContainer &rays,
2552	int &sampleContributions,
2553	int &contributingSamples)
2554	{
2555	sampleContributions = 0;
2556	contributingSamples = 0;
2557
2558	BoundedRayContainer::const_iterator it, it_end = rays.end();
2559
2560	ViewCell *vc = leaf->GetViewCell();
2561
2562	// add contributions from samples to the PVS
2563	for (it = rays.begin(); it != it_end; ++ it)
2564	{
2565	int contribution = 0;
2566	Ray ray = (it)->mRay;
2567	float relContribution;
2568	if (!ray->intersections.empty())
2569	contribution += vc->GetPvs().AddSample(ray->intersections[0].mObject,
2570	1.0f,
2571	relContribution);
2572
2573	if (ray->sourceObject.mObject)
2574	contribution += vc->GetPvs().AddSample(ray->sourceObject.mObject,
2575	1.0f,
2576	relContribution);
2577
2578	if (contribution)
2579	{
2580	sampleContributions += contribution;
2581	++ contributingSamples;
2582	}
2583
2584	//if (ray->mFlags & Ray::STORE_BSP_INTERSECTIONS)
2585	// ray->bspIntersections.push_back(Ray::BspIntersection((*it)->mMinT, this));
2586	}
2587	}
2588
2589
2590	int BspTree::ComputePvsSize(const BoundedRayContainer &rays) const
2591	{
2592	int pvsSize = 0;
2593
2594	BoundedRayContainer::const_iterator rit, rit_end = rays.end();
2595
2596	Intersectable::NewMail();
2597
2598	for (rit = rays.begin(); rit != rays.end(); ++ rit)
2599	{
2600	Ray ray = (rit)->mRay;
2601
2602	if (!ray->intersections.empty())
2603	{
2604	if (!ray->intersections[0].mObject->Mailed())
2605	{
2606	ray->intersections[0].mObject->Mail();
2607	++ pvsSize;
2608	}
2609	}
2610	if (ray->sourceObject.mObject)
2611	{
2612	if (!ray->sourceObject.mObject->Mailed())
2613	{
2614	ray->sourceObject.mObject->Mail();
2615	++ pvsSize;
2616	}
2617	}
2618	}
2619
2620	return pvsSize;
2621	}
2622
2623
2624	float BspTree::GetEpsilon() const
2625	{
2626	return mEpsilon;
2627	}
2628
2629
2630	int BspTree::CollectMergeCandidates(const vector<BspLeaf *> leaves,
2631	vector<MergeCandidate> &candidates)
2632	{
2633	BspLeaf::NewMail();
2634
2635	vector<BspLeaf *>::const_iterator it, it_end = leaves.end();
2636
2637	int numCandidates = 0;
2638
2639	// find merge candidates and push them into queue
2640	for (it = leaves.begin(); it != it_end; ++ it)
2641	{
2642	BspLeaf leaf = it;
2643
2644	// the same leaves must not be part of two merge candidates
2645	leaf->Mail();
2646	vector<BspLeaf *> neighbors;
2647	FindNeighbors(leaf, neighbors, true);
2648
2649	vector<BspLeaf *>::const_iterator nit, nit_end = neighbors.end();
2650
2651	// TODO: test if at least one ray goes from one leaf to the other
2652	for (nit = neighbors.begin(); nit != nit_end; ++ nit)
2653	{
2654	if ((*nit)->GetViewCell() != leaf->GetViewCell())
2655	{
2656	MergeCandidate mc(leaf->GetViewCell(), (*nit)->GetViewCell());
2657	candidates.push_back(mc);
2658
2659	++ numCandidates;
2660	if ((numCandidates % 1000) == 0)
2661	{
2662	cout << "collected " << numCandidates << " merge candidates" << endl;
2663	}
2664	}
2665	}
2666	}
2667
2668	Debug << "merge queue: " << (int)candidates.size() << endl;
2669	Debug << "leaves in queue: " << numCandidates << endl;
2670
2671
2672	return (int)leaves.size();
2673	}
2674
2675
2676	int BspTree::CollectMergeCandidates(const VssRayContainer &rays,
2677	vector<MergeCandidate> &candidates)
2678	{
2679	ViewCell::NewMail();
2680	long startTime = GetTime();
2681
2682	map<BspLeaf , vector<BspLeaf> > neighborMap;
2683	ViewCellContainer::const_iterator iit;
2684
2685	int numLeaves = 0;
2686
2687	BspLeaf::NewMail();
2688
2689	for (int i = 0; i < (int)rays.size(); ++ i)
2690	{
2691	VssRay *ray = rays[i];
2692
2693	// traverse leaves stored in the rays and compare and
2694	// merge consecutive leaves (i.e., the neighbors in the tree)
2695	if (ray->mViewCells.size() < 2)
2696	continue;
2697
2698	iit = ray->mViewCells.begin();
2699	BspViewCell bspVc = dynamic_cast<BspViewCell >(*(iit ++));
2700	BspLeaf *leaf = bspVc->mLeaf;
2701
2702	// traverse intersections
2703	// consecutive leaves are neighbors => add them to queue
2704	for (; iit != ray->mViewCells.end(); ++ iit)
2705	{
2706	// next pair
2707	BspLeaf *prevLeaf = leaf;
2708	bspVc = dynamic_cast<BspViewCell >(iit);
2709	leaf = bspVc->mLeaf;
2710
2711	// view space not valid or same view cell
2712	if (!leaf->TreeValid() \|\| !prevLeaf->TreeValid() \|\|
2713	(leaf->GetViewCell() == prevLeaf->GetViewCell()))
2714	continue;
2715
2716	vector<BspLeaf *> &neighbors = neighborMap[leaf];
2717
2718	bool found = false;
2719
2720	// both leaves inserted in queue already =>
2721	// look if double pair already exists
2722	if (leaf->Mailed() && prevLeaf->Mailed())
2723	{
2724	vector<BspLeaf *>::const_iterator it, it_end = neighbors.end();
2725
2726	for (it = neighbors.begin(); !found && (it != it_end); ++ it)
2727	if (*it == prevLeaf)
2728	found = true; // already in queue
2729	}
2730
2731	if (!found)
2732	{
2733	// this pair is not in map yet
2734	// => insert into the neighbor map and the queue
2735	neighbors.push_back(prevLeaf);
2736	neighborMap[prevLeaf].push_back(leaf);
2737
2738	leaf->Mail();
2739	prevLeaf->Mail();
2740
2741	MergeCandidate mc(leaf->GetViewCell(), prevLeaf->GetViewCell());
2742
2743	candidates.push_back(mc);
2744
2745	if (((int)candidates.size() % 1000) == 0)
2746	{
2747	cout << "collected " << (int)candidates.size() << " merge candidates" << endl;
2748	}
2749	}
2750	}
2751	}
2752
2753	Debug << "neighbormap size: " << (int)neighborMap.size() << endl;
2754	Debug << "merge queue: " << (int)candidates.size() << endl;
2755	Debug << "leaves in queue: " << numLeaves << endl;
2756
2757
2758	//-- collect the leaves which haven't been found by ray casting
2759	#if 0
2760	cout << "finding additional merge candidates using geometry" << endl;
2761	vector<BspLeaf *> leaves;
2762	CollectLeaves(leaves, true);
2763	Debug << "found " << (int)leaves.size() << " new leaves" << endl << endl;
2764	CollectMergeCandidates(leaves, candidates);
2765	#endif
2766
2767	return numLeaves;
2768	}
2769
2770
2771
2772
2773	/***************************************************************/
2774	/* BspNodeGeometry Implementation */
2775	/***************************************************************/
2776
2777
2778	BspNodeGeometry::BspNodeGeometry(const BspNodeGeometry &rhs)
2779	{
2780	mPolys.reserve(rhs.mPolys.size());
2781
2782	PolygonContainer::const_iterator it, it_end = rhs.mPolys.end();
2783	for (it = rhs.mPolys.begin(); it != it_end; ++ it)
2784	{
2785	Polygon3 poly = it;
2786	mPolys.push_back(new Polygon3(*poly));
2787	}
2788	}
2789
2790
2791	BspNodeGeometry::~BspNodeGeometry()
2792	{
2793	CLEAR_CONTAINER(mPolys);
2794	}
2795
2796
2797	float BspNodeGeometry::GetArea() const
2798	{
2799	return Polygon3::GetArea(mPolys);
2800	}
2801
2802
2803	float BspNodeGeometry::GetVolume() const
2804	{
2805	//-- compute volume using tetrahedralization of the geometry
2806	// and adding the volume of the single tetrahedrons
2807	float volume = 0;
2808	const float f = 1.0f / 6.0f;
2809
2810	PolygonContainer::const_iterator pit, pit_end = mPolys.end();
2811
2812	// note: can take arbitrary point, e.g., the origin. However,
2813	// we rather take the center of mass to prevents precision errors
2814	const Vector3 center = CenterOfMass();
2815
2816	for (pit = mPolys.begin(); pit != pit_end; ++ pit)
2817	{
2818	Polygon3 poly = pit;
2819	const Vector3 v0 = poly->mVertices[0] - center;
2820
2821	for (int i = 1; i < (int)poly->mVertices.size() - 1; ++ i)
2822	{
2823	const Vector3 v1 = poly->mVertices[i] - center;
2824	const Vector3 v2 = poly->mVertices[i + 1] - center;
2825
2826	volume += f * (DotProd(v0, CrossProd(v1, v2)));
2827	}
2828	}
2829
2830	return volume;
2831	}
2832
2833
2834	Vector3 BspNodeGeometry::CenterOfMass() const
2835	{
2836	int n = 0;
2837
2838	Vector3 center(0,0,0);
2839
2840	PolygonContainer::const_iterator pit, pit_end = mPolys.end();
2841
2842	for (pit = mPolys.begin(); pit != pit_end; ++ pit)
2843	{
2844	Polygon3 poly = pit;
2845
2846	VertexContainer::const_iterator vit, vit_end = poly->mVertices.end();
2847
2848	for(vit = poly->mVertices.begin(); vit != vit_end; ++ vit)
2849	{
2850	center += *vit;
2851	++ n;
2852	}
2853	}
2854
2855	return center / (float)n;
2856	}
2857
2858
2859	void BspNodeGeometry::AddToMesh(Mesh &mesh)
2860	{
2861	PolygonContainer::const_iterator it, it_end = mPolys.end();
2862
2863	for (it = mPolys.begin(); it != mPolys.end(); ++ it)
2864	{
2865	(*it)->AddToMesh(mesh);
2866	}
2867	}
2868
2869
2870	void BspNodeGeometry::SplitGeometry(BspNodeGeometry &front,
2871	BspNodeGeometry &back,
2872	const Plane3 &splitPlane,
2873	const AxisAlignedBox3 &box,
2874	const float epsilon) const
2875	{
2876	// get cross section of new polygon
2877	Polygon3 *planePoly = box.CrossSection(splitPlane);
2878
2879	// split polygon with all other polygons
2880	planePoly = SplitPolygon(planePoly, epsilon);
2881
2882	//-- new polygon splits all other polygons
2883	for (int i = 0; i < (int)mPolys.size(); ++ i)
2884	{
2885	/// don't use epsilon here to get exact split planes
2886	const int cf =
2887	mPolys[i]->ClassifyPlane(splitPlane, Limits::Small);
2888
2889	switch (cf)
2890	{
2891	case Polygon3::SPLIT:
2892	{
2893	Polygon3 *poly = new Polygon3(mPolys[i]->mVertices);
2894
2895	Polygon3 *frontPoly = new Polygon3();
2896	Polygon3 *backPoly = new Polygon3();
2897
2898	poly->Split(splitPlane,
2899	*frontPoly,
2900	*backPoly,
2901	epsilon);
2902
2903	DEL_PTR(poly);
2904
2905	if (frontPoly->Valid(epsilon))
2906	front.mPolys.push_back(frontPoly);
2907	else
2908	DEL_PTR(frontPoly);
2909
2910	if (backPoly->Valid(epsilon))
2911	back.mPolys.push_back(backPoly);
2912	else
2913	DEL_PTR(backPoly);
2914	}
2915
2916	break;
2917	case Polygon3::BACK_SIDE:
2918	back.mPolys.push_back(new Polygon3(mPolys[i]->mVertices));
2919	break;
2920	case Polygon3::FRONT_SIDE:
2921	front.mPolys.push_back(new Polygon3(mPolys[i]->mVertices));
2922	break;
2923	case Polygon3::COINCIDENT:
2924	//front.mPolys.push_back(CreateReversePolygon(mPolys[i]));
2925	back.mPolys.push_back(new Polygon3(mPolys[i]->mVertices));
2926	break;
2927	default:
2928	break;
2929	}
2930	}
2931
2932	//-- finally add the new polygon to the child node geometries
2933	if (planePoly)
2934	{
2935	// add polygon with normal pointing into positive half space to back cell
2936	back.mPolys.push_back(planePoly);
2937	// add polygon with reverse orientation to front cell
2938	front.mPolys.push_back(planePoly->CreateReversePolygon());
2939	}
2940	}
2941
2942
2943	Polygon3 BspNodeGeometry::SplitPolygon(Polygon3 planePoly,
2944	const float epsilon) const
2945	{
2946	if (!planePoly->Valid(epsilon))
2947	DEL_PTR(planePoly);
2948
2949	// polygon is split by all other planes
2950	for (int i = 0; (i < (int)mPolys.size()) && planePoly; ++ i)
2951	{
2952	Plane3 plane = mPolys[i]->GetSupportingPlane();
2953
2954	/// don't use epsilon here to get exact split planes
2955	const int cf =
2956	planePoly->ClassifyPlane(plane, Limits::Small);
2957
2958	// split new polygon with all previous planes
2959	switch (cf)
2960	{
2961	case Polygon3::SPLIT:
2962	{
2963	Polygon3 *frontPoly = new Polygon3();
2964	Polygon3 *backPoly = new Polygon3();
2965
2966	planePoly->Split(plane,
2967	*frontPoly,
2968	*backPoly,
2969	epsilon);
2970
2971	// don't need anymore
2972	DEL_PTR(planePoly);
2973	DEL_PTR(frontPoly);
2974
2975	// back polygon is belonging to geometry
2976	if (backPoly->Valid(epsilon))
2977	planePoly = backPoly;
2978	else
2979	DEL_PTR(backPoly);
2980	}
2981	break;
2982	case Polygon3::FRONT_SIDE:
2983	DEL_PTR(planePoly);
2984	break;
2985	// polygon is taken as it is
2986	case Polygon3::BACK_SIDE:
2987	case Polygon3::COINCIDENT:
2988	default:
2989	break;
2990	}
2991	}
2992
2993	return planePoly;
2994	}
2995
2996
2997	ViewCell *
2998	BspTree::GetViewCell(const Vector3 &point)
2999	{
3000	if (mRoot == NULL)
3001	return NULL;
3002
3003
3004	stack<BspNode *> nodeStack;
3005	nodeStack.push(mRoot);
3006
3007	ViewCell *viewcell = NULL;
3008
3009	while (!nodeStack.empty()) {
3010	BspNode *node = nodeStack.top();
3011	nodeStack.pop();
3012
3013	if (node->IsLeaf()) {
3014	viewcell = dynamic_cast<BspLeaf *>(node)->mViewCell;
3015	break;
3016	} else {
3017
3018	BspInterior interior = dynamic_cast<BspInterior >(node);
3019
3020	// random decision
3021	if (interior->GetPlane().Side(point) < 0)
3022	nodeStack.push(interior->GetBack());
3023	else
3024	nodeStack.push(interior->GetFront());
3025	}
3026	}
3027
3028	return viewcell;
3029	}
3030
3031
3032	void BspNodeGeometry::IncludeInBox(AxisAlignedBox3 &box)
3033	{
3034	Polygon3::IncludeInBox(mPolys, box);
3035	}
3036
3037
3038	bool BspTree::Export(ofstream &stream)
3039	{
3040	ExportNode(mRoot, stream);
3041
3042	return true;
3043	}
3044
3045
3046	void BspTree::ExportNode(BspNode *node, ofstream &stream)
3047	{
3048	if (node->IsLeaf())
3049	{
3050	BspLeaf leaf = dynamic_cast<BspLeaf >(node);
3051
3052	int id = -1;
3053	if (leaf->GetViewCell() != mOutOfBoundsCell)
3054	id = leaf->GetViewCell()->GetId();
3055
3056	stream << "<Leaf viewCellId=\"" << id << "\" />" << endl;
3057	}
3058	else
3059	{
3060	BspInterior interior = dynamic_cast<BspInterior >(node);
3061
3062	Plane3 plane = interior->GetPlane();
3063	stream << "<Interior plane=\"" << plane.mNormal.x << " "
3064	<< plane.mNormal.y << " " << plane.mNormal.z << " "
3065	<< plane.mD << "\">" << endl;
3066
3067	ExportNode(interior->GetBack(), stream);
3068	ExportNode(interior->GetFront(), stream);
3069
3070	stream << "</Interior>" << endl;
3071	}
3072	}

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