95 lines
5.4 KiB
Text
95 lines
5.4 KiB
Text
// This file is part of Eigen, a lightweight C++ template library
|
|
// for linear algebra.
|
|
//
|
|
// Copyright (C) 2009 Ilya Baran <ibaran@mit.edu>
|
|
//
|
|
// This Source Code Form is subject to the terms of the Mozilla
|
|
// Public License v. 2.0. If a copy of the MPL was not distributed
|
|
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
|
|
|
#ifndef EIGEN_BVH_MODULE_H
|
|
#define EIGEN_BVH_MODULE_H
|
|
|
|
#include "../../Eigen/Core"
|
|
#include "../../Eigen/Geometry"
|
|
#include "../../Eigen/StdVector"
|
|
#include <algorithm>
|
|
#include <queue>
|
|
|
|
namespace Eigen {
|
|
|
|
/**
|
|
* \defgroup BVH_Module BVH module
|
|
* \brief This module provides generic bounding volume hierarchy algorithms
|
|
* and reference tree implementations.
|
|
*
|
|
*
|
|
* \code
|
|
* #include <unsupported/Eigen/BVH>
|
|
* \endcode
|
|
*
|
|
* A bounding volume hierarchy (BVH) can accelerate many geometric queries. This module provides a generic implementation
|
|
* of the two basic algorithms over a BVH: intersection of a query object against all objects in the hierarchy and minimization
|
|
* of a function over the objects in the hierarchy. It also provides intersection and minimization over a cartesian product of
|
|
* two BVH's. A BVH accelerates intersection by using the fact that if a query object does not intersect a volume, then it cannot
|
|
* intersect any object contained in that volume. Similarly, a BVH accelerates minimization because the minimum of a function
|
|
* over a volume is no greater than the minimum of a function over any object contained in it.
|
|
*
|
|
* Some sample queries that can be written in terms of intersection are:
|
|
* - Determine all points where a ray intersects a triangle mesh
|
|
* - Given a set of points, determine which are contained in a query sphere
|
|
* - Given a set of spheres, determine which contain the query point
|
|
* - Given a set of disks, determine if any is completely contained in a query rectangle (represent each 2D disk as a point \f$(x,y,r)\f$
|
|
* in 3D and represent the rectangle as a pyramid based on the original rectangle and shrinking in the \f$r\f$ direction)
|
|
* - Given a set of points, count how many pairs are \f$d\pm\epsilon\f$ apart (done by looking at the cartesian product of the set
|
|
* of points with itself)
|
|
*
|
|
* Some sample queries that can be written in terms of function minimization over a set of objects are:
|
|
* - Find the intersection between a ray and a triangle mesh closest to the ray origin (function is infinite off the ray)
|
|
* - Given a polyline and a query point, determine the closest point on the polyline to the query
|
|
* - Find the diameter of a point cloud (done by looking at the cartesian product and using negative distance as the function)
|
|
* - Determine how far two meshes are from colliding (this is also a cartesian product query)
|
|
*
|
|
* This implementation decouples the basic algorithms both from the type of hierarchy (and the types of the bounding volumes) and
|
|
* from the particulars of the query. To enable abstraction from the BVH, the BVH is required to implement a generic mechanism
|
|
* for traversal. To abstract from the query, the query is responsible for keeping track of results.
|
|
*
|
|
* To be used in the algorithms, a hierarchy must implement the following traversal mechanism (see KdBVH for a sample implementation): \code
|
|
typedef Volume //the type of bounding volume
|
|
typedef Object //the type of object in the hierarchy
|
|
typedef Index //a reference to a node in the hierarchy--typically an int or a pointer
|
|
typedef VolumeIterator //an iterator type over node children--returns Index
|
|
typedef ObjectIterator //an iterator over object (leaf) children--returns const Object &
|
|
Index getRootIndex() const //returns the index of the hierarchy root
|
|
const Volume &getVolume(Index index) const //returns the bounding volume of the node at given index
|
|
void getChildren(Index index, VolumeIterator &outVBegin, VolumeIterator &outVEnd,
|
|
ObjectIterator &outOBegin, ObjectIterator &outOEnd) const
|
|
//getChildren takes a node index and makes [outVBegin, outVEnd) range over its node children
|
|
//and [outOBegin, outOEnd) range over its object children
|
|
\endcode
|
|
*
|
|
* To use the hierarchy, call BVIntersect or BVMinimize, passing it a BVH (or two, for cartesian product) and a minimizer or intersector.
|
|
* For an intersection query on a single BVH, the intersector encapsulates the query and must provide two functions:
|
|
* \code
|
|
bool intersectVolume(const Volume &volume) //returns true if the query intersects the volume
|
|
bool intersectObject(const Object &object) //returns true if the intersection search should terminate immediately
|
|
\endcode
|
|
* The guarantee that BVIntersect provides is that intersectObject will be called on every object whose bounding volume
|
|
* intersects the query (but possibly on other objects too) unless the search is terminated prematurely. It is the
|
|
* responsibility of the intersectObject function to keep track of the results in whatever manner is appropriate.
|
|
* The cartesian product intersection and the BVMinimize queries are similar--see their individual documentation.
|
|
*
|
|
* The following is a simple but complete example for how to use the BVH to accelerate the search for a closest red-blue point pair:
|
|
* \include BVH_Example.cpp
|
|
* Output: \verbinclude BVH_Example.out
|
|
*/
|
|
}
|
|
|
|
//@{
|
|
|
|
#include "src/BVH/BVAlgorithms.h"
|
|
#include "src/BVH/KdBVH.h"
|
|
|
|
//@}
|
|
|
|
#endif // EIGEN_BVH_MODULE_H
|