#include <Eigen/StdVector> #include <unsupported/Eigen/BVH> #include <iostream> using namespace Eigen; typedef AlignedBox<double, 2> Box2d; namespace Eigen { Box2d bounding_box(const Vector2d &v) { return Box2d(v, v); } //compute the bounding box of a single point } struct PointPointMinimizer //how to compute squared distances between points and rectangles { PointPointMinimizer() : calls(0) {} typedef double Scalar; double minimumOnVolumeVolume(const Box2d &r1, const Box2d &r2) { ++calls; return r1.squaredExteriorDistance(r2); } double minimumOnVolumeObject(const Box2d &r, const Vector2d &v) { ++calls; return r.squaredExteriorDistance(v); } double minimumOnObjectVolume(const Vector2d &v, const Box2d &r) { ++calls; return r.squaredExteriorDistance(v); } double minimumOnObjectObject(const Vector2d &v1, const Vector2d &v2) { ++calls; return (v1 - v2).squaredNorm(); } int calls; }; int main() { typedef std::vector<Vector2d, aligned_allocator<Vector2d> > StdVectorOfVector2d; StdVectorOfVector2d redPoints, bluePoints; for(int i = 0; i < 100; ++i) { //initialize random set of red points and blue points redPoints.push_back(Vector2d::Random()); bluePoints.push_back(Vector2d::Random()); } PointPointMinimizer minimizer; double minDistSq = std::numeric_limits<double>::max(); //brute force to find closest red-blue pair for(int i = 0; i < (int)redPoints.size(); ++i) for(int j = 0; j < (int)bluePoints.size(); ++j) minDistSq = std::min(minDistSq, minimizer.minimumOnObjectObject(redPoints[i], bluePoints[j])); std::cout << "Brute force distance = " << sqrt(minDistSq) << ", calls = " << minimizer.calls << std::endl; //using BVH to find closest red-blue pair minimizer.calls = 0; KdBVH<double, 2, Vector2d> redTree(redPoints.begin(), redPoints.end()), blueTree(bluePoints.begin(), bluePoints.end()); //construct the trees minDistSq = BVMinimize(redTree, blueTree, minimizer); //actual BVH minimization call std::cout << "BVH distance = " << sqrt(minDistSq) << ", calls = " << minimizer.calls << std::endl; return 0; }