mitsuba/include/mitsuba/core/octree.h

206 lines
6.5 KiB
C++

/*
This file is part of Mitsuba, a physically based rendering system.
Copyright (c) 2007-2010 by Wenzel Jakob and others.
Mitsuba is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License Version 3
as published by the Free Software Foundation.
Mitsuba is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#if !defined(__OCTREE_H)
#define __OCTREE_H
#include <mitsuba/mitsuba.h>
#include <mitsuba/core/aabb.h>
MTS_NAMESPACE_BEGIN
/**
* \brief Generic multiple-reference octree.
*
* Based on the excellent implementation in PBRT. Modifications are
* the addition of a bounding sphere query and support for multithreading.
*/
template <typename T> class Octree {
public:
inline Octree(const AABB &aabb, int maxDepth = 16)
: m_aabb(aabb), m_maxDepth(maxDepth) {
}
inline void insert(const T &value, const AABB &coverage) {
insert(&m_root, m_aabb, value, coverage,
coverage.getExtents().lengthSquared(), 0);
}
/// Execute operator() of <tt>functor</tt> on all records, which potentially overlap <tt>p</tt>
template <typename Functor> inline void lookup(const Point &p, Functor &functor) const {
if (!m_aabb.contains(p))
return;
lookup(&m_root, m_aabb, p, functor);
}
/// Execute operator() of <tt>functor</tt> on all records, which potentially overlap <tt>bsphere</tt>
template <typename Functor> inline void searchSphere(const BSphere &sphere, Functor &functor) {
if (!m_aabb.overlaps(sphere))
return;
searchSphere(&m_root, m_aabb, sphere, functor);
}
inline const AABB &getAABB() const { return m_aabb; }
private:
struct OctreeNode {
public:
OctreeNode() {
pthread_rwlock_init(&lock, NULL);
for (int i=0; i<8; ++i)
children[i] = NULL;
}
~OctreeNode() {
pthread_rwlock_destroy(&lock);
for (int i=0; i<8; ++i) {
if (children[i])
delete children[i];
}
}
inline void readLock() const { pthread_rwlock_rdlock(&lock); }
inline void readUnlock() const { pthread_rwlock_unlock(&lock); }
inline void writeLock() { pthread_rwlock_wrlock(&lock); }
inline void writeUnlock() { pthread_rwlock_unlock(&lock); }
OctreeNode *children[8];
mutable pthread_rwlock_t lock;
std::vector<T> data;
};
void insert(OctreeNode *node, const AABB &nodeAABB, const T &value,
const AABB &coverage, Float diag2, int depth) {
/* Add the data item to the current octree node if the max. tree
depth is reached or the data item's coverage area is smaller
than the current node size */
if (depth == m_maxDepth ||
(nodeAABB.getExtents().lengthSquared() < diag2)) {
node->writeLock();
node->data.push_back(value);
node->writeUnlock();
return;
}
/* Otherwise: test for overlap */
const Point center = nodeAABB.getCenter();
bool over[8];
AABB childAABB;
over[0] = over[1] = over[2] = over[3] = (coverage.min.x <= center.x);
over[4] = over[5] = over[6] = over[7] = (coverage.max.x > center.x);
over[0] &= (coverage.min.y <= center.y);
over[1] &= (coverage.min.y <= center.y);
over[4] &= (coverage.min.y <= center.y);
over[5] &= (coverage.min.y <= center.y);
over[2] &= (coverage.max.y > center.y);
over[3] &= (coverage.max.y > center.y);
over[6] &= (coverage.max.y > center.y);
over[7] &= (coverage.max.y > center.y);
over[0] &= (coverage.min.z <= center.z);
over[2] &= (coverage.min.z <= center.z);
over[4] &= (coverage.min.z <= center.z);
over[6] &= (coverage.min.z <= center.z);
over[1] &= (coverage.max.z > center.z);
over[3] &= (coverage.max.z > center.z);
over[5] &= (coverage.max.z > center.z);
over[7] &= (coverage.max.z > center.z);
/* Recurse */
for (int child=0; child<8; ++child) {
if (!over[child])
continue;
if (!node->children[child]) {
node->writeLock();
node->children[child] = new OctreeNode();
node->writeUnlock();
}
childAABB.min.x = (child & 4) ? center.x : nodeAABB.min.x;
childAABB.max.x = (child & 4) ? nodeAABB.max.x : center.x;
childAABB.min.y = (child & 2) ? center.y : nodeAABB.min.y;
childAABB.max.y = (child & 2) ? nodeAABB.max.y : center.y;
childAABB.min.z = (child & 1) ? center.z : nodeAABB.min.z;
childAABB.max.z = (child & 1) ? nodeAABB.max.z : center.z;
insert(node->children[child], childAABB,
value, coverage, diag2, depth+1);
}
}
/// Internal lookup procedure - const version
template <typename Functor> inline void lookup(const OctreeNode *node,
const AABB &nodeAABB, const Point &p, Functor &functor) const {
const Point center = nodeAABB.getCenter();
node->readLock();
for (size_t i=0; i<node->data.size(); ++i)
functor(node->data[i]);
int child = (p.x > center.x ? 4 : 0)
+ (p.y > center.y ? 2 : 0)
+ (p.z > center.z ? 1 : 0);
OctreeNode *childNode = node->children[child];
node->readUnlock();
if (childNode) {
AABB childAABB;
childAABB.min.x = (child & 4) ? center.x : nodeAABB.min.x;
childAABB.max.x = (child & 4) ? nodeAABB.max.x : center.x;
childAABB.min.y = (child & 2) ? center.y : nodeAABB.min.y;
childAABB.max.y = (child & 2) ? nodeAABB.max.y : center.y;
childAABB.min.z = (child & 1) ? center.z : nodeAABB.min.z;
childAABB.max.z = (child & 1) ? nodeAABB.max.z : center.z;
lookup(node->children[child], childAABB, p, functor);
}
}
template <typename Functor> inline void searchSphere(OctreeNode *node,
const AABB &nodeAABB, const BSphere &sphere,
Functor &functor) {
const Point center = nodeAABB.getCenter();
node->readLock();
for (size_t i=0; i<node->data.size(); ++i)
functor(node->data[i]);
node->readUnlock();
// Potential for much optimization..
for (int child=0; child<8; ++child) {
if (node->children[child]) {
AABB childAABB;
childAABB.min.x = (child & 4) ? center.x : nodeAABB.min.x;
childAABB.max.x = (child & 4) ? nodeAABB.max.x : center.x;
childAABB.min.y = (child & 2) ? center.y : nodeAABB.min.y;
childAABB.max.y = (child & 2) ? nodeAABB.max.y : center.y;
childAABB.min.z = (child & 1) ? center.z : nodeAABB.min.z;
childAABB.max.z = (child & 1) ? nodeAABB.max.z : center.z;
if (childAABB.overlaps(sphere))
searchSphere(node->children[child], childAABB, sphere, functor);
}
}
}
private:
OctreeNode m_root;
AABB m_aabb;
int m_maxDepth;
};
MTS_NAMESPACE_END
#endif /* __OCTREE_H */