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source: trunk/VUT/GtpVisibilityPreprocessor/src/ViewCellBsp.cpp @ 573

Revision 573, 69.0 KB checked in by mattausch, 18 years ago (diff)
implemented functtion for view cell construction

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

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