content: package emu.grasscutter.scripts;
  
  import com.github.davidmoten.rtreemulti.Entry;
  import com.github.davidmoten.rtreemulti.RTree;
  import com.github.davidmoten.rtreemulti.geometry.Geometry;
  import com.github.davidmoten.rtreemulti.geometry.Rectangle;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  import java.util.function.Function;
  
  public class SceneIndexManager {
  
      public static <T> RTree<T, Geometry> buildIndex(int dimensions, Collection<T> elements, Function<T, Geometry> extractor){
          RTree<T, Geometry> rtree = RTree.dimensions(dimensions).create();
          return rtree.add(elements.stream().map(e -> Entry.entry(e, extractor.apply(e))).toList());
      }
      public static <T> List<T> queryNeighbors(RTree<T, Geometry> tree, double[] position, int range){
          var result = new ArrayList<T>();
          Rectangle rectangle = Rectangle.create(calRange(position, -range), calRange(position, range));
          var queryResult = tree.search(rectangle);
          queryResult.forEach(q -> result.add(q.value()));
          return result;
      }
      private static double[] calRange(double[] position, int range){
          var newPos = position.clone();
          for(int i=0;i<newPos.length;i++){
              newPos[i] += range;
          }
          return newPos;
      }
  }
  