Unity 2D草预制体空白区域实例化性能优化问题咨询

我有一个草预制体，生长一段时间后会在自身周围8个位置中随机选一个实例化自身，最终形成预制体格网。最初我为每个预制体配置了8个触发碰撞体来检测对应位置是否存在其他草预制体，配置截图如下：

该方案运行后仅实例化少量预制体，Unity就会出现明显卡顿。

原有实现代码 #

using UnityEngine;
public class GrassController : MonoBehaviour
{
    [SerializeField] private float growthRate = 1.1f;
    [SerializeField] private float maxSize = 1f;
    [SerializeField] private float reproduceEffort = 0.1f;
    [SerializeField] private GameObject prefab;
    [SerializeField] private GameObject sprite;
    [SerializeField] private ReproduceHitBoxController[] reproduceHitBoxes;
    [SerializeField] private float size = 0f;
    private float initialSize = 0.1f;
    private void Awake()
    {
        size = initialSize;
        ApplyGrowth();
    }
    private void FixedUpdate()
    {
        if (size < maxSize) Grow();
        else Reproduce();
    }
    private void Grow()
    {
        size *= growthRate;
        if (size >= maxSize) size = maxSize;
        ApplyGrowth();
    }
    private void ApplyGrowth()
    {
        sprite.transform.localScale = new Vector3(size, size, sprite.transform.position.z);
    }
    private void Reproduce()
    {
        var reproduceHitBox = reproduceHitBoxes[Random.Range(0, reproduceHitBoxes.Length)];
        if (reproduceHitBox.tagInCollider == true) return;
        Instantiate(prefab, reproduceHitBox.transform.position, Quaternion.identity);
        size -= reproduceEffort;
    }
}

问题排查 #

经性能分析，卡顿主要来自大量物理碰撞检测带来的开销，需要找到性能更优的方案来检测指定区域内是否存在其他草对象，性能分析截图如下：

优化方案 #

最终采用Dictionary<Vector3,GrassController>按位置存储所有已生成的草对象，每次繁殖时仅需检测相邻位置是否存在于字典中即可，完全规避了物理检测开销。
注意：有开发者指出该方案存在潜在的浮点数精度问题，实际使用时建议将坐标转换为整数对作为字典键，避免因精度误差导致位置匹配错误。

优化后代码 #

using UnityEngine;
public class GrassController : MonoBehaviour
{
    [SerializeField] private float growthRate = 1.1f;
    [SerializeField] private float maxSize = 1f;
    [SerializeField] private float reproduceEffort = 0.1f;
    [SerializeField] private GameObject prefab;
    [SerializeField] private GameObject sprite;
    [SerializeField] private GameController gameController;
    [SerializeField] private float size = 0f;
    private Vector3[] growPoints;
    private float initialSize = 0.1f;
    private void Awake()
    {
        growPoints = new Vector3[] {
            new Vector3(transform.position.x + 1, transform.position.y + 1, transform.position.z),
            new Vector3(transform.position.x + 1, transform.position.y, transform.position.z),
            new Vector3(transform.position.x + 1, transform.position.y - 1, transform.position.z),
            new Vector3(transform.position.x, transform.position.y - 1, transform.position.z),
            new Vector3(transform.position.x - 1, transform.position.y - 1, transform.position.z),
            new Vector3(transform.position.x - 1, transform.position.y, transform.position.z),
            new Vector3(transform.position.x - 1, transform.position.y + 1, transform.position.z),
            new Vector3(transform.position.x, transform.position.y + 1, transform.position.z),
        };
        size = initialSize;
        gameController.grassControllers.Add(transform.position, this);
        ApplyGrowth();
    }
    private void FixedUpdate()
    {
        if (size < maxSize) Grow();
        else Reproduce();
    }
    private void Grow()
    {
        size *= growthRate;
        if (size >= maxSize) size = maxSize;
        ApplyGrowth();
    }
    private void ApplyGrowth()
    {
        sprite.transform.localScale = new Vector3(size, size, sprite.transform.position.z);
    }
    private void Reproduce()
    {
        var growPoint = growPoints[Random.Range(0, growPoints.Length)];
        if (gameController.grassControllers.ContainsKey(growPoint) == true) return;
        Instantiate(prefab, growPoint, Quaternion.identity);
        size -= reproduceEffort;
    }
}

最终效果 #

优化后运行流畅，符合预期效果，截图如下：

内容的提问来源于stack exchange，提问作者Lucas Venturini