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Src/Core/Quadtree/QuadtreeNode.cs

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+using System;
+using System.Buffers;
+using System.Collections.Concurrent;
+using Unity.Mathematics;
+using System.Collections.Generic;
+
+namespace Net.BITKit.Quadtree
+{
+    public struct QuadtreeNode
+    {
+        public readonly Quadtree Root;
+
+        public int Depth;
+        
+        public float2 Center; // 节点中心
+        public float2 Size;   // 节点大小
+
+        public readonly QuadtreeNode[] Children; // 子节点
+        public readonly HashSet<int> Objects;       // 存储的对象ID
+
+        public QuadtreeNode(Quadtree root,float2 center, float2 size)
+        {
+            Root = root;
+            Center = center;
+            Size = size;
+            
+            Children = new QuadtreeNode[4];
+            
+            Objects = new HashSet<int>();
+
+            Depth = 0;
+        }
+
+        public bool Contains(float2 point)
+        {
+            var min = Center - Size * 0.5f;
+            var max = Center + Size * 0.5f;
+    
+            return math.all(point >= min & point <= max);
+        }
+
+        public void Split()
+        {
+            var childSize = Size / 2;
+            var offset = childSize / 2;
+
+            foreach (var node in Children)
+            {
+                foreach (var id in Objects)
+                {
+                    var pos = Root.Positions[id];
+                    if (node.Contains(pos))
+                    {
+                        node.Objects.Add(id);
+                    }
+                }
+            }
+
+            Objects.Clear();
+
+            Children[0] = new QuadtreeNode(Root, Center + new float2(-offset.x, offset.y), childSize)
+            {
+                Depth = Depth + 1,
+            };
+            Children[1] = new QuadtreeNode(Root, Center + new float2(offset.x, offset.y), childSize)
+            {
+                Depth = Depth + 1,
+            };
+            Children[2] = new QuadtreeNode(Root, Center + new float2(-offset.x, -offset.y), childSize)
+            {
+                Depth = Depth + 1,
+            };
+            Children[3] = new QuadtreeNode(Root, Center + new float2(offset.x, -offset.y), childSize)
+            {
+                Depth = Depth + 1,
+            };
+        }
+
+        public bool IsLeaf()
+        {
+            return Children[0].Size.x == 0; // 如果子节点未初始化，说明是叶子节点
+        }
+    }
+}