0029702: Foundation Classes - Introduce possibility to control parallel execution...
[occt.git] / src / BVH / BVH_LinearBuilder.hxx
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0ef61b50 1// Created on: 2014-09-11
2// Created by: Danila ULYANOV
3// Copyright (c) 2013-2014 OPEN CASCADE SAS
4//
5// This file is part of Open CASCADE Technology software library.
6//
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
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#ifndef _BVH_LinearBuilder_Header
17#define _BVH_LinearBuilder_Header
18
3a507ddb 19#include <BVH_RadixSorter.hxx>
e28f12b3 20#include <Standard_Assert.hxx>
0ef61b50 21
22//! Performs fast BVH construction using LBVH building approach.
23//! Algorithm uses spatial Morton codes to reduce the BVH construction
24//! problem to a sorting problem (radix sort -- O(N) complexity). This
25//! Linear Bounding Volume Hierarchy (LBVH) builder produces BVH trees
26//! of lower quality compared to SAH-based BVH builders but it is over
27//! an order of magnitude faster (up to 3M triangles per second).
28//!
29//! For more details see:
30//! C. Lauterbach, M. Garland, S. Sengupta, D. Luebke, and D. Manocha.
31//! Fast BVH construction on GPUs. Eurographics, 2009.
32template<class T, int N>
33class BVH_LinearBuilder : public BVH_Builder<T, N>
34{
35public:
36
37 typedef typename BVH::VectorType<T, N>::Type BVH_VecNt;
38
39public:
40
41 //! Creates binned LBVH builder.
f5b72419 42 BVH_LinearBuilder (const Standard_Integer theLeafNodeSize = BVH_Constants_LeafNodeSizeDefault,
43 const Standard_Integer theMaxTreeDepth = BVH_Constants_MaxTreeDepth);
0ef61b50 44
45 //! Releases resources of LBVH builder.
46 virtual ~BVH_LinearBuilder();
47
48 //! Builds BVH.
e28f12b3 49 virtual void Build (BVH_Set<T, N>* theSet,
50 BVH_Tree<T, N>* theBVH,
51 const BVH_Box<T, N>& theBox) const Standard_OVERRIDE;
0ef61b50 52
53protected:
54
e28f12b3 55 typedef NCollection_Array1<BVH_EncodedLink>::iterator LinkIterator;
3a507ddb 56
57protected:
58
0ef61b50 59 //! Emits hierarchy from sorted Morton codes.
e28f12b3 60 Standard_Integer emitHierachy (BVH_Tree<T, N>* theBVH,
61 const NCollection_Array1<BVH_EncodedLink>& theEncodedLinks,
3a507ddb 62 const Standard_Integer theBit,
63 const Standard_Integer theShift,
64 const Standard_Integer theStart,
e28f12b3 65 const Standard_Integer theFinal) const;
3a507ddb 66
67 //! Returns index of the first element which does not compare less than the given one.
e28f12b3 68 Standard_Integer lowerBound (const NCollection_Array1<BVH_EncodedLink>& theEncodedLinks,
69 Standard_Integer theStart,
3a507ddb 70 Standard_Integer theFinal,
e28f12b3 71 Standard_Integer theDigit) const;
3a507ddb 72
e28f12b3 73};
3a507ddb 74
e28f12b3 75// =======================================================================
76// function : BVH_LinearBuilder
77// purpose :
78// =======================================================================
79template<class T, int N>
80BVH_LinearBuilder<T, N>::BVH_LinearBuilder (const Standard_Integer theLeafNodeSize,
81 const Standard_Integer theMaxTreeDepth)
82: BVH_Builder<T, N> (theLeafNodeSize,
83 theMaxTreeDepth)
84{
85 //
86}
0ef61b50 87
e28f12b3 88// =======================================================================
89// function : ~BVH_LinearBuilder
90// purpose :
91// =======================================================================
92template<class T, int N>
93BVH_LinearBuilder<T, N>::~BVH_LinearBuilder()
94{
95 //
96}
97
98// =======================================================================
99// function : lowerBound
100// purpose : Returns index of first element greater than the given one
101// =======================================================================
102template<class T, int N>
103Standard_Integer BVH_LinearBuilder<T, N>::lowerBound (const NCollection_Array1<BVH_EncodedLink>& theEncodedLinks,
104 Standard_Integer theStart,
105 Standard_Integer theFinal,
106 Standard_Integer theDigit) const
107{
108 Standard_Integer aNbPrims = theFinal - theStart;
109 while (aNbPrims > 0)
110 {
111 const Standard_Integer aStep = aNbPrims / 2;
112 if (theEncodedLinks.Value (theStart + aStep).first & (1 << theDigit))
113 {
114 aNbPrims = aStep;
115 }
116 else
117 {
118 theStart += aStep + 1;
119 aNbPrims -= aStep + 1;
120 }
121 }
122
123 return theStart;
124}
125
126// =======================================================================
127// function : emitHierachy
128// purpose : Emits hierarchy from sorted Morton codes
129// =======================================================================
130template<class T, int N>
131Standard_Integer BVH_LinearBuilder<T, N>::emitHierachy (BVH_Tree<T, N>* theBVH,
132 const NCollection_Array1<BVH_EncodedLink>& theEncodedLinks,
133 const Standard_Integer theBit,
134 const Standard_Integer theShift,
135 const Standard_Integer theStart,
136 const Standard_Integer theFinal) const
137{
138 if (theFinal - theStart > BVH_Builder<T, N>::myLeafNodeSize)
139 {
140 const Standard_Integer aPosition = theBit < 0 ?
141 (theStart + theFinal) / 2 : lowerBound (theEncodedLinks, theStart, theFinal, theBit);
142 if (aPosition == theStart || aPosition == theFinal)
143 {
144 return emitHierachy (theBVH, theEncodedLinks, theBit - 1, theShift, theStart, theFinal);
145 }
146
147 // Build inner node
148 const Standard_Integer aNode = theBVH->AddInnerNode (0, 0);
149 const Standard_Integer aRghNode = theShift + aPosition - theStart;
150
151 const Standard_Integer aLftChild = emitHierachy (theBVH, theEncodedLinks, theBit - 1, theShift, theStart, aPosition);
152 const Standard_Integer aRghChild = emitHierachy (theBVH, theEncodedLinks, theBit - 1, aRghNode, aPosition, theFinal);
153
154 theBVH->NodeInfoBuffer()[aNode].y() = aLftChild;
155 theBVH->NodeInfoBuffer()[aNode].z() = aRghChild;
156 return aNode;
157 }
158 else
159 {
160 // Build leaf node
161 return theBVH->AddLeafNode (theShift, theShift + theFinal - theStart - 1);
162 }
163}
164
165namespace BVH
166{
167 //! Calculates bounding boxes (AABBs) for the given BVH tree.
168 template<class T, int N>
169 Standard_Integer UpdateBounds (BVH_Set<T, N>* theSet, BVH_Tree<T, N>* theTree, const Standard_Integer theNode = 0)
170 {
171 const BVH_Vec4i aData = theTree->NodeInfoBuffer()[theNode];
172 if (aData.x() == 0)
173 {
174 const Standard_Integer aLftChild = theTree->NodeInfoBuffer()[theNode].y();
175 const Standard_Integer aRghChild = theTree->NodeInfoBuffer()[theNode].z();
176
177 const Standard_Integer aLftDepth = UpdateBounds (theSet, theTree, aLftChild);
178 const Standard_Integer aRghDepth = UpdateBounds (theSet, theTree, aRghChild);
179
180 typename BVH_Box<T, N>::BVH_VecNt aLftMinPoint = theTree->MinPointBuffer()[aLftChild];
181 typename BVH_Box<T, N>::BVH_VecNt aLftMaxPoint = theTree->MaxPointBuffer()[aLftChild];
182 typename BVH_Box<T, N>::BVH_VecNt aRghMinPoint = theTree->MinPointBuffer()[aRghChild];
183 typename BVH_Box<T, N>::BVH_VecNt aRghMaxPoint = theTree->MaxPointBuffer()[aRghChild];
184
185 BVH::BoxMinMax<T, N>::CwiseMin (aLftMinPoint, aRghMinPoint);
186 BVH::BoxMinMax<T, N>::CwiseMax (aLftMaxPoint, aRghMaxPoint);
187
188 theTree->MinPointBuffer()[theNode] = aLftMinPoint;
189 theTree->MaxPointBuffer()[theNode] = aLftMaxPoint;
190 return Max (aLftDepth, aRghDepth) + 1;
191 }
192 else
193 {
194 typename BVH_Box<T, N>::BVH_VecNt& aMinPoint = theTree->MinPointBuffer()[theNode];
195 typename BVH_Box<T, N>::BVH_VecNt& aMaxPoint = theTree->MaxPointBuffer()[theNode];
196 for (Standard_Integer aPrimIdx = aData.y(); aPrimIdx <= aData.z(); ++aPrimIdx)
197 {
198 const BVH_Box<T, N> aBox = theSet->Box (aPrimIdx);
199 if (aPrimIdx == aData.y())
200 {
201 aMinPoint = aBox.CornerMin();
202 aMaxPoint = aBox.CornerMax();
203 }
204 else
205 {
206 BVH::BoxMinMax<T, N>::CwiseMin (aMinPoint, aBox.CornerMin());
207 BVH::BoxMinMax<T, N>::CwiseMax (aMaxPoint, aBox.CornerMax());
208 }
209 }
210 }
211 return 0;
212 }
213
e28f12b3 214 template<class T, int N>
da555fc2 215 struct BoundData
e28f12b3 216 {
da555fc2 217 BVH_Set <T, N>* mySet; //!< Set of geometric objects
e28f12b3 218 BVH_Tree<T, N>* myBVH; //!< BVH tree built over the set
219 Standard_Integer myNode; //!< BVH node to update bounding box
220 Standard_Integer myLevel; //!< Level of the processed BVH node
221 Standard_Integer* myHeight; //!< Height of the processed BVH node
da555fc2 222 };
e28f12b3 223
da555fc2 224 //! Task for parallel bounds updating.
225 template<class T, int N>
226 class UpdateBoundTask
227 {
e28f12b3 228 public:
229
3c7a61ea 230 UpdateBoundTask (const Standard_Boolean isParallel)
231 : myIsParallel (isParallel)
232 {
233 }
234
e28f12b3 235 //! Executes the task.
da555fc2 236 void operator()(const BoundData<T, N>& theData) const
e28f12b3 237 {
da555fc2 238 if (theData.myBVH->IsOuter (theData.myNode) || theData.myLevel > 2)
e28f12b3 239 {
da555fc2 240 *theData.myHeight = BVH::UpdateBounds (theData.mySet, theData.myBVH, theData.myNode);
e28f12b3 241 }
242 else
243 {
244 Standard_Integer aLftHeight = 0;
245 Standard_Integer aRghHeight = 0;
246
da555fc2 247 const Standard_Integer aLftChild = theData.myBVH->NodeInfoBuffer()[theData.myNode].y();
248 const Standard_Integer aRghChild = theData.myBVH->NodeInfoBuffer()[theData.myNode].z();
e28f12b3 249
da555fc2 250 std::vector<BoundData<T, N> > aList;
251 aList.reserve (2);
252 if (!theData.myBVH->IsOuter (aLftChild))
e28f12b3 253 {
da555fc2 254 BoundData<T, N> aBoundData = {theData.mySet, theData.myBVH, aLftChild, theData.myLevel + 1, &aLftHeight};
255 aList.push_back (aBoundData);
e28f12b3 256 }
257 else
258 {
da555fc2 259 aLftHeight = BVH::UpdateBounds (theData.mySet, theData.myBVH, aLftChild);
e28f12b3 260 }
261
da555fc2 262 if (!theData.myBVH->IsOuter (aRghChild))
e28f12b3 263 {
da555fc2 264 BoundData<T, N> aBoundData = {theData.mySet, theData.myBVH, aRghChild, theData.myLevel + 1, &aRghHeight};
265 aList.push_back (aBoundData);
e28f12b3 266 }
267 else
268 {
da555fc2 269 aRghHeight = BVH::UpdateBounds (theData.mySet, theData.myBVH, aRghChild);
e28f12b3 270 }
271
da555fc2 272 if (!aList.empty())
e28f12b3 273 {
3c7a61ea 274 OSD_Parallel::ForEach (aList.begin (), aList.end (), UpdateBoundTask<T, N> (myIsParallel), !myIsParallel);
e28f12b3 275 }
276
da555fc2 277 typename BVH_Box<T, N>::BVH_VecNt aLftMinPoint = theData.myBVH->MinPointBuffer()[aLftChild];
278 typename BVH_Box<T, N>::BVH_VecNt aLftMaxPoint = theData.myBVH->MaxPointBuffer()[aLftChild];
279 typename BVH_Box<T, N>::BVH_VecNt aRghMinPoint = theData.myBVH->MinPointBuffer()[aRghChild];
280 typename BVH_Box<T, N>::BVH_VecNt aRghMaxPoint = theData.myBVH->MaxPointBuffer()[aRghChild];
e28f12b3 281
282 BVH::BoxMinMax<T, N>::CwiseMin (aLftMinPoint, aRghMinPoint);
283 BVH::BoxMinMax<T, N>::CwiseMax (aLftMaxPoint, aRghMaxPoint);
284
da555fc2 285 theData.myBVH->MinPointBuffer()[theData.myNode] = aLftMinPoint;
286 theData.myBVH->MaxPointBuffer()[theData.myNode] = aLftMaxPoint;
e28f12b3 287
da555fc2 288 *theData.myHeight = Max (aLftHeight, aRghHeight) + 1;
e28f12b3 289 }
e28f12b3 290 }
3c7a61ea 291
292 private:
293
294 Standard_Boolean myIsParallel;
e28f12b3 295 };
e28f12b3 296}
297
298// =======================================================================
299// function : Build
300// purpose :
301// =======================================================================
302template<class T, int N>
303void BVH_LinearBuilder<T, N>::Build (BVH_Set<T, N>* theSet,
304 BVH_Tree<T, N>* theBVH,
305 const BVH_Box<T, N>& theBox) const
306{
d0bcf7aa 307 Standard_STATIC_ASSERT (N == 2 || N == 3 || N == 4);
e28f12b3 308 const Standard_Integer aSetSize = theSet->Size();
309 if (theBVH == NULL || aSetSize == 0)
310 {
311 return;
312 }
313
314 theBVH->Clear();
315
316 // Step 0 -- Initialize parameter of virtual grid
317 BVH_RadixSorter<T, N> aRadixSorter (theBox);
3c7a61ea 318 aRadixSorter.SetParallel (this->IsParallel());
e28f12b3 319
320 // Step 1 - Perform radix sorting of primitive set
321 aRadixSorter.Perform (theSet);
322
323 // Step 2 -- Emitting BVH hierarchy from sorted Morton codes
324 emitHierachy (theBVH, aRadixSorter.EncodedLinks(), 29, 0, 0, theSet->Size());
325
326 // Step 3 -- Compute bounding boxes of BVH nodes
327 theBVH->MinPointBuffer().resize (theBVH->NodeInfoBuffer().size());
328 theBVH->MaxPointBuffer().resize (theBVH->NodeInfoBuffer().size());
329
330 Standard_Integer aHeight = 0;
da555fc2 331 BVH::BoundData<T, N> aBoundData = { theSet, theBVH, 0, 0, &aHeight };
3c7a61ea 332 BVH::UpdateBoundTask<T, N> aBoundTask (this->IsParallel());
da555fc2 333 aBoundTask (aBoundData);
0ef61b50 334
e28f12b3 335 BVH_Builder<T, N>::updateDepth (theBVH, aHeight);
336}
0ef61b50 337
338#endif // _BVH_LinearBuilder_Header