Add BVH module in unsupported (patch from Ilya Baran)

(I thought I committed it a week ago but it seems the command failed)

2 files changed, 62 insertions, 0 deletions

diff --git a/unsupported/doc/examples/BVH_Example.cpp b/unsupported/doc/examples/BVH_Example.cpp
new file mode 100644
index 000000000..890eb535b
--- /dev/null
+++ b/unsupported/doc/examples/BVH_Example.cpp
@@ -0,0 +1,45 @@
+#include <unsupported/Eigen/BVH>
+
+using namespace Eigen;
+typedef AlignedBox<double, 2> Box2d;
+
+Box2d ei_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()
+{
+  std::vector<Vector2d> 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;
+}
diff --git a/unsupported/doc/examples/CMakeLists.txt b/unsupported/doc/examples/CMakeLists.txt
new file mode 100644
index 000000000..af4de4b0d
--- /dev/null
+++ b/unsupported/doc/examples/CMakeLists.txt
@@ -0,0 +1,17 @@
+FILE(GLOB examples_SRCS "*.cpp")
+
+ADD_CUSTOM_TARGET(unsupported_examples)
+
+FOREACH(example_src ${examples_SRCS})
+GET_FILENAME_COMPONENT(example ${example_src} NAME_WE)
+ADD_EXECUTABLE(${example} ${example_src})
+GET_TARGET_PROPERTY(example_executable
+                    ${example} LOCATION)
+ADD_CUSTOM_COMMAND(
+  TARGET ${example}
+  POST_BUILD
+  COMMAND ${example_executable}
+  ARGS >${CMAKE_CURRENT_BINARY_DIR}/${example}.out
+)
+ADD_DEPENDENCIES(unsupported_examples ${example})
+ENDFOREACH(example_src)