rj-action-library/Runtime/Structures/Spatial/QuadTree/QuadTreeCell.cs

using System.Collections;
using System.Collections.Generic;
using Godot;
using System;



namespace Rokojori
{
  public class QuadTreeCell<T>:QuadTreeNode<T>
  { 
    QuadTreeCell<T> _parent;
    public QuadTreeCell<T> parent => _parent;

    QuadTree<T> _tree;
    public QuadTree<T> tree => _tree;

    List<QuadTreeCell<T>> _cells;
    public List<QuadTreeCell<T>> cells => _cells;


    public int numCells => _cells == null ? 0 : cells.Count;

    List<T> _values;
    public List<T> values => _values;

    int _depth;
    public int depth => _depth;

    Vector2 _center;
    public Vector2 center => _center;

    Vector2 _size;  
    public Vector2 size => _size;

    bool _isCombined = false;
    public bool isCombined => _isCombined;
    public bool canBeCombined => ! isLeaf && ! isCombined && numCells > 0;
    

    public bool isRoot => _parent == null;
    public bool isEmpty => _cells == null || _cells.Count == 0;
    public bool isLeaf => _depth == tree.maxDepth;

    Box2 _box;
    public Box2 box => _box;

    int _rootCellIndex = -1;
    public int rootCellIndex => _rootCellIndex;
    

    public void GetInsideBox( Box2 box, List<T> list )
    {
      if ( ! _box.Overlaps( box ) )
      {
        return;
      }

      if ( _values != null )
      {
        list.AddRange( _values );
      }

      if ( _cells == null )
      {
        return;
      }

      _cells.ForEach( c => c.GetInsideBox( box, list ) );

    }

    public static QuadTreeCell<T> Create( QuadTree<T> tree, Vector2 min, Vector2 max, int rootIndex )
    {
      var cell = new QuadTreeCell<T>();
      cell._tree = tree;
      cell._center = (max + min ) / 2f;
      cell._size = ( max - min );
      cell._depth = 0;
      cell._box = Box2.Create( min, max );
      cell._rootCellIndex = rootIndex;

      return cell;
    }

    public static QuadTreeCell<T> Create( QuadTreeCell<T> parent, int depth, Vector2 min, Vector2 max )
    {
      var cell = new QuadTreeCell<T>();
      cell._parent = parent;
      cell._tree = parent.tree;
      cell._center = (max + min ) / 2f;
      cell._size = ( max - min );
      cell._depth = depth;
      cell._box = Box2.Create( min, max );
      cell._rootCellIndex = parent.rootCellIndex;

      return cell;
    }

    public Vector2 GetPointWithPolarUV( Vector2 polarUV )
    {
      var halfSize = _size / 2f;

      return _center + halfSize * polarUV;
    }

    public void BoxInsert( T data, Box2 box )
    {
      if ( ! _box.Overlaps( box ) )
      {
        return;
      }

      if ( isLeaf )
      {
        if ( _values == null )
        {
          _values = new List<T>();
        }

        values.Add( data );
        return;
      }

      Nest();

      cells.ForEach( c => c.BoxInsert( data, box ) );

      return;
    }


    public bool Insert( T data )
    {
      if ( isLeaf )
      {
        if ( _values == null )
        {
          _values = new List<T>();
        }

        values.Add( data );
        return true;
      }
     
      Nest();

      var position = tree.GetPosition( data );

      var cell = GetChildCellFor( position );

      if ( cell == null )
      {
        RJLog.Log( "No cell found in:", this.depth, this.center, ">> for: ", position );

        return false;
      }

      return cell.Insert( data );
    }

    public void SmoothDown( float amount )
    {
      if ( isLeaf || cells == null )
      {
        return;
      }

      cells.ForEach(
        ( c )=>
        {
          c._values = tree.SmoothPoints( c.values, values, amount );
        }
      ); 

    }

    public void Combine()
    {
      if ( isLeaf || isCombined )
      {
        return;
      }

      if ( numCells == 0 )
      {
        _isCombined = true;
        return;
      }

      var cellPoints = new List<T>();
      cells.ForEach(
        c => 
        {
          if ( c.values == null )
          {
            return;
          }

          cellPoints.AddRange( c.values );
        }
      );

      _values = tree.CombinePoints( cellPoints );
      _isCombined = true;
    }

    public QuadTreeCell<T> GetChildCellFor( Vector2 position )
    {
      return _cells.Find( c => c.box.ContainsPoint( position ) );
    }


    public void Nest()
    {
      if ( _cells != null && _cells.Count == 8 )
      {
        return;
      }

      _cells = new List<QuadTreeCell<T>>();

      for ( int x = -1; x < 1; x ++ )
      {        
        var x0 = x;
        var x1 = x + 1;

        for ( int y = -1; y < 1; y ++ )
        {
          var y0 = y;
          var y1 = y + 1;

          
          var min = GetPointWithPolarUV( new Vector2( x0, y0 ) );
          var max = GetPointWithPolarUV( new Vector2( x1, y1 ) );

          _cells.Add( Create( this, depth + 1, min, max ) );
          
        }
      }
    }
  }
}