core: shapes: Union: provide override for is_inside.

src/core/shapes/Union.hpp

@@ -20,6 +20,7 @@
 #ifndef SHAPES_UNION
 #define SHAPES_UNION
 
+#include <boost/range/numeric.hpp>
 #include <memory>
 
 #include "Shape.hpp"
@@ -66,6 +67,14 @@ class Union : public Shape {
                         dist_compare);
   }
 
+  bool is_inside(Utils::Vector3d const &pos) const override {
+    return boost::accumulate(
+        m_shapes, false,
+        [&pos](bool inside, std::shared_ptr<Shapes::Shape> const &s) {
+          return inside && s->is_inside(pos);
+        });
+  }
+
 private:
   std::vector<std::shared_ptr<Shapes::Shape>> m_shapes;
 };