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1 | // Created on: 2013-12-20 |
2 | // Created by: Denis BOGOLEPOV |
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3 | // Copyright (c) 2013-2014 OPEN CASCADE SAS |
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4 | // |
5 | // This file is part of Open CASCADE Technology software library. |
6 | // |
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7 | // This library is free software; you can redistribute it and/or modify it under |
8 | // the terms of the GNU Lesser General Public License version 2.1 as published |
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9 | // by the Free Software Foundation, with special exception defined in the file |
10 | // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT |
11 | // distribution for complete text of the license and disclaimer of any warranty. |
12 | // |
13 | // Alternatively, this file may be used under the terms of Open CASCADE |
14 | // commercial license or contractual agreement. |
15 | |
16 | // ======================================================================= |
17 | // function : BVH_BinnedBuilder |
18 | // purpose : |
19 | // ======================================================================= |
20 | template<class T, int N, int Bins> |
21 | BVH_BinnedBuilder<T, N, Bins>::BVH_BinnedBuilder (const Standard_Integer theLeafNodeSize, |
22 | const Standard_Integer theMaxTreeDepth) |
23 | : BVH_Builder<T, N> (theLeafNodeSize, |
24 | theMaxTreeDepth) |
25 | { |
26 | // |
27 | } |
28 | |
29 | // ======================================================================= |
30 | // function : ~BVH_BinnedBuilder |
31 | // purpose : |
32 | // ======================================================================= |
33 | template<class T, int N, int Bins> |
34 | BVH_BinnedBuilder<T, N, Bins>::~BVH_BinnedBuilder() |
35 | { |
36 | // |
37 | } |
38 | |
39 | // ======================================================================= |
40 | // function : GetSubVolumes |
41 | // purpose : |
42 | // ======================================================================= |
43 | template<class T, int N, int Bins> |
44 | void BVH_BinnedBuilder<T, N, Bins>::GetSubVolumes (BVH_Set<T, N>* theSet, |
45 | BVH_Tree<T, N>* theBVH, |
46 | const Standard_Integer theNode, |
47 | BVH_BinVector& theBins, |
48 | const Standard_Integer theAxis) |
49 | { |
50 | const T aMin = BVHTools::VecComp<T, N>::Get (theBVH->MinPoint (theNode), theAxis); |
51 | const T aMax = BVHTools::VecComp<T, N>::Get (theBVH->MaxPoint (theNode), theAxis); |
52 | |
53 | const T anInvStep = static_cast<T> (Bins) / (aMax - aMin); |
54 | |
55 | for (Standard_Integer anIdx = theBVH->BegPrimitive (theNode); anIdx <= theBVH->EndPrimitive (theNode); ++anIdx) |
56 | { |
57 | typename BVH_Set<T, N>::BVH_BoxNt aBox = theSet->Box (anIdx); |
58 | |
59 | Standard_Integer aBinIndex = static_cast<Standard_Integer> (std::floor ((theSet->Center (anIdx, theAxis) - aMin) * anInvStep)); |
60 | if (aBinIndex < 0) |
61 | { |
62 | aBinIndex = 0; |
63 | } |
64 | else if (aBinIndex >= Bins) |
65 | { |
66 | aBinIndex = Bins - 1; |
67 | } |
68 | |
69 | theBins[aBinIndex].Count++; |
70 | theBins[aBinIndex].Box.Combine (aBox); |
71 | } |
72 | } |
73 | |
74 | namespace BVHTools |
75 | { |
76 | // ======================================================================= |
77 | // function : SplitPrimitives |
78 | // purpose : |
79 | // ======================================================================= |
80 | template<class T, int N> |
81 | Standard_Integer SplitPrimitives (BVH_Set<T, N>* theSet, |
82 | const BVH_Box<T, N>& theBox, |
83 | const Standard_Integer theBeg, |
84 | const Standard_Integer theEnd, |
85 | const Standard_Integer theBin, |
86 | const Standard_Integer theAxis, |
87 | const Standard_Integer theBins) |
88 | { |
89 | const T aMin = BVHTools::VecComp<T, N>::Get (theBox.CornerMin(), theAxis); |
90 | const T aMax = BVHTools::VecComp<T, N>::Get (theBox.CornerMax(), theAxis); |
91 | |
92 | const T anInvStep = static_cast<T> (theBins) / (aMax - aMin); |
93 | |
94 | Standard_Integer aLftIdx (theBeg); |
95 | Standard_Integer aRghIdx (theEnd); |
96 | |
97 | do |
98 | { |
99 | while ((Standard_Integer) std::floor ((theSet->Center (aLftIdx, theAxis) - aMin) * anInvStep) <= theBin && aLftIdx < theEnd) |
100 | { |
101 | ++aLftIdx; |
102 | } |
103 | while ((Standard_Integer) std::floor ((theSet->Center (aRghIdx, theAxis) - aMin) * anInvStep) > theBin && aRghIdx > theBeg) |
104 | { |
105 | --aRghIdx; |
106 | } |
107 | |
108 | if (aLftIdx <= aRghIdx) |
109 | { |
110 | if (aLftIdx != aRghIdx) |
111 | { |
112 | theSet->Swap (aLftIdx, aRghIdx); |
113 | } |
114 | |
115 | ++aLftIdx; |
116 | --aRghIdx; |
117 | } |
118 | } while (aLftIdx <= aRghIdx); |
119 | |
120 | return aLftIdx; |
121 | } |
122 | } |
123 | |
124 | #if defined (_WIN32) && defined (max) |
125 | #undef max |
126 | #endif |
127 | |
128 | #include <limits> |
129 | |
130 | // ======================================================================= |
131 | // function : BuildNode |
132 | // purpose : |
133 | // ======================================================================= |
134 | template<class T, int N, int Bins> |
135 | void BVH_BinnedBuilder<T, N, Bins>::BuildNode (BVH_Set<T, N>* theSet, |
136 | BVH_Tree<T, N>* theBVH, |
137 | const Standard_Integer theNode) |
138 | { |
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139 | const Standard_Integer aNodeBegPrimitive = theBVH->BegPrimitive (theNode); |
140 | const Standard_Integer aNodeEndPrimitive = theBVH->EndPrimitive (theNode); |
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141 | |
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142 | if (aNodeEndPrimitive - aNodeBegPrimitive < BVH_Builder<T, N>::myLeafNodeSize) |
143 | { |
144 | return; // node does not require partitioning |
145 | } |
146 | |
147 | const BVH_Box<T, N> anAABB (theBVH->MinPoint (theNode), |
148 | theBVH->MaxPoint (theNode)); |
149 | |
150 | const typename BVH_Box<T, N>::BVH_VecNt aSize = anAABB.Size(); |
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151 | |
152 | // Parameters for storing best split |
153 | Standard_Integer aMinSplitAxis = -1; |
154 | Standard_Integer aMinSplitIndex = 0; |
155 | Standard_Integer aMinSplitNumLft = 0; |
156 | Standard_Integer aMinSplitNumRgh = 0; |
157 | |
158 | BVH_Box<T, N> aMinSplitBoxLft; |
159 | BVH_Box<T, N> aMinSplitBoxRgh; |
160 | |
161 | Standard_Real aMinSplitCost = std::numeric_limits<Standard_Real>::max(); |
162 | |
163 | // Find best split |
164 | for (Standard_Integer anAxis = 0; anAxis < (N < 4 ? N : 3); ++anAxis) |
165 | { |
166 | if (BVHTools::VecComp<T, N>::Get (aSize, anAxis) <= THE_NODE_MIN_SIZE) |
167 | continue; |
168 | |
169 | BVH_BinVector aBins; |
170 | GetSubVolumes (theSet, theBVH, theNode, aBins, anAxis); |
171 | |
172 | // Choose the best split (with minimum SAH cost) |
173 | for (Standard_Integer aSplit = 1; aSplit < Bins; ++aSplit) |
174 | { |
175 | Standard_Integer aLftCount = 0; |
176 | Standard_Integer aRghCount = 0; |
177 | |
178 | BVH_Box<T, N> aLftAABB; |
179 | BVH_Box<T, N> aRghAABB; |
180 | |
181 | for (Standard_Integer anIndex = 0; anIndex < aSplit; ++anIndex) |
182 | { |
183 | aLftCount += aBins[anIndex].Count; |
184 | aLftAABB.Combine (aBins[anIndex].Box); |
185 | } |
186 | |
187 | for (Standard_Integer anIndex = aSplit; anIndex < Bins; ++anIndex) |
188 | { |
189 | aRghCount += aBins[anIndex].Count; |
190 | aRghAABB.Combine (aBins[anIndex].Box); |
191 | } |
192 | |
193 | // Simple SAH evaluation |
194 | Standard_Real aCost = (static_cast<Standard_Real> (aLftAABB.Area()) /* / aNodeArea */) * aLftCount |
195 | + (static_cast<Standard_Real> (aRghAABB.Area()) /* / aNodeArea */) * aRghCount; |
196 | |
197 | if (aCost <= aMinSplitCost) |
198 | { |
199 | aMinSplitCost = aCost; |
200 | aMinSplitAxis = anAxis; |
201 | aMinSplitIndex = aSplit; |
202 | aMinSplitBoxLft = aLftAABB; |
203 | aMinSplitBoxRgh = aRghAABB; |
204 | aMinSplitNumLft = aLftCount; |
205 | aMinSplitNumRgh = aRghCount; |
206 | } |
207 | } |
208 | } |
209 | |
210 | if (aMinSplitAxis == -1) |
211 | { |
212 | return; |
213 | } |
214 | |
215 | theBVH->SetInner (theNode); |
216 | |
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217 | Standard_Integer aMiddle = -1; |
218 | |
219 | if (aMinSplitNumLft == 0 || aMinSplitNumRgh == 0) // case of objects with the same center |
220 | { |
221 | aMinSplitBoxLft.Clear(); |
222 | aMinSplitBoxRgh.Clear(); |
223 | |
224 | aMiddle = std::max (aNodeBegPrimitive + 1, |
225 | static_cast<Standard_Integer> ((aNodeBegPrimitive + aNodeEndPrimitive) / 2.f)); |
226 | |
227 | aMinSplitNumLft = aMiddle - aNodeBegPrimitive; |
228 | |
229 | for (Standard_Integer anIndex = aNodeBegPrimitive; anIndex < aMiddle; ++anIndex) |
230 | { |
231 | aMinSplitBoxLft.Combine (theSet->Box (anIndex)); |
232 | } |
233 | |
234 | aMinSplitNumRgh = aNodeEndPrimitive - aMiddle + 1; |
235 | |
236 | for (Standard_Integer anIndex = aNodeEndPrimitive; anIndex >= aMiddle; --anIndex) |
237 | { |
238 | aMinSplitBoxRgh.Combine (theSet->Box (anIndex)); |
239 | } |
240 | } |
241 | else |
242 | { |
243 | aMiddle = BVHTools::SplitPrimitives<T, N> (theSet, anAABB, |
244 | aNodeBegPrimitive, aNodeEndPrimitive, aMinSplitIndex - 1, aMinSplitAxis, Bins); |
245 | } |
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246 | |
247 | static const Standard_Integer aLftNode = 1; |
248 | static const Standard_Integer aRghNode = 2; |
249 | |
250 | // Setting up tasks for child nodes |
251 | for (Standard_Integer aSide = aLftNode; aSide <= aRghNode; ++aSide) |
252 | { |
253 | typename BVH_Box<T, N>::BVH_VecNt aMinPoint = (aSide == aLftNode) |
254 | ? aMinSplitBoxLft.CornerMin() |
255 | : aMinSplitBoxRgh.CornerMin(); |
256 | typename BVH_Box<T, N>::BVH_VecNt aMaxPoint = (aSide == aLftNode) |
257 | ? aMinSplitBoxLft.CornerMax() |
258 | : aMinSplitBoxRgh.CornerMax(); |
259 | |
260 | Standard_Integer aBegPrimitive = (aSide == aLftNode) |
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261 | ? aNodeBegPrimitive |
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262 | : aMiddle; |
263 | Standard_Integer aEndPrimitive = (aSide == aLftNode) |
264 | ? aMiddle - 1 |
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265 | : aNodeEndPrimitive; |
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266 | |
267 | Standard_Integer aChildIndex = theBVH->AddLeafNode (aMinPoint, aMaxPoint, aBegPrimitive, aEndPrimitive); |
268 | |
269 | theBVH->Level (aChildIndex) = theBVH->Level (theNode) + 1; |
270 | |
271 | // Check to see if child node must be split |
272 | const Standard_Integer aNbPimitives = (aSide == aLftNode) |
273 | ? aMinSplitNumLft |
274 | : aMinSplitNumRgh; |
275 | |
276 | if (aSide == aLftNode) |
277 | theBVH->LeftChild (theNode) = aChildIndex; |
278 | else |
279 | theBVH->RightChild (theNode) = aChildIndex; |
280 | |
281 | const Standard_Boolean isLeaf = aNbPimitives <= BVH_Builder<T, N>::myLeafNodeSize |
282 | || theBVH->Level (aChildIndex) >= BVH_Builder<T, N>::myMaxTreeDepth; |
283 | |
284 | if (!isLeaf) |
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285 | { |
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286 | BVH_Builder<T, N>::myTasksQueue.Append (aChildIndex); |
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287 | } |
288 | |
289 | BVH_Builder<T, N>::UpdateDepth (theBVH, theBVH->Level (aChildIndex)); |
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290 | } |
291 | } |