ScenePartition/Runtime/SceneGrid.cs

using System;
using System.Collections.Generic;
using UnityEngine;

namespace VertexColor.ScenePartition.Editor
{
    [Serializable]
    public class SceneGrid
    {
        [SerializeField]
        private int cellSize = 10;

        [SerializeField]
        private SceneGridDictionary grid = new SceneGridDictionary();

        public void Insert(uint id, Vector2 point)
        {
            Vector2 gridPos = CalculateGridPosition(point);
            if (grid.TryGetValue(gridPos, out List<uint> ids))
            {
                ids.Add(id);
            }
            else
            {
                grid.Add(gridPos, new List<uint> { id });
            }
        }

        public Vector2 CalculateGridPosition(Vector2 point)
        {
            int x = Mathf.FloorToInt(point.x / cellSize);
            int y = Mathf.FloorToInt(point.y / cellSize);

            return new Vector2(x, y);
        }
    }
}