1 #include <Eigen/StdVector> 2 #include <unsupported/Eigen/BVH> 3 #include <iostream> 4 5 using namespace Eigen; 6 typedef AlignedBox<double, 2> Box2d; 7 8 namespace Eigen { 9 namespace internal { 10 Box2d bounding_box(const Vector2d &v) { return Box2d(v, v); } //compute the bounding box of a single point 11 } 12 } 13 14 struct PointPointMinimizer //how to compute squared distances between points and rectangles 15 { 16 PointPointMinimizer() : calls(0) {} 17 typedef double Scalar; 18 19 double minimumOnVolumeVolume(const Box2d &r1, const Box2d &r2) { ++calls; return r1.squaredExteriorDistance(r2); } 20 double minimumOnVolumeObject(const Box2d &r, const Vector2d &v) { ++calls; return r.squaredExteriorDistance(v); } 21 double minimumOnObjectVolume(const Vector2d &v, const Box2d &r) { ++calls; return r.squaredExteriorDistance(v); } 22 double minimumOnObjectObject(const Vector2d &v1, const Vector2d &v2) { ++calls; return (v1 - v2).squaredNorm(); } 23 24 int calls; 25 }; 26 27 int main() 28 { 29 typedef std::vector<Vector2d, aligned_allocator<Vector2d> > StdVectorOfVector2d; 30 StdVectorOfVector2d redPoints, bluePoints; 31 for(int i = 0; i < 100; ++i) { //initialize random set of red points and blue points 32 redPoints.push_back(Vector2d::Random()); 33 bluePoints.push_back(Vector2d::Random()); 34 } 35 36 PointPointMinimizer minimizer; 37 double minDistSq = std::numeric_limits<double>::max(); 38 39 //brute force to find closest red-blue pair 40 for(int i = 0; i < (int)redPoints.size(); ++i) 41 for(int j = 0; j < (int)bluePoints.size(); ++j) 42 minDistSq = std::min(minDistSq, minimizer.minimumOnObjectObject(redPoints[i], bluePoints[j])); 43 std::cout << "Brute force distance = " << sqrt(minDistSq) << ", calls = " << minimizer.calls << std::endl; 44 45 //using BVH to find closest red-blue pair 46 minimizer.calls = 0; 47 KdBVH<double, 2, Vector2d> redTree(redPoints.begin(), redPoints.end()), blueTree(bluePoints.begin(), bluePoints.end()); //construct the trees 48 minDistSq = BVMinimize(redTree, blueTree, minimizer); //actual BVH minimization call 49 std::cout << "BVH distance = " << sqrt(minDistSq) << ", calls = " << minimizer.calls << std::endl; 50 51 return 0; 52 } 53
