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