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

public class MeshCombineTool : MonoBehaviour
{
    [MenuItem("Tools/Mesh/Combine Selected Meshes")]
    static void CombineMeshes()
    {
        GameObject[] selectedObjects = Selection.gameObjects;

        if (selectedObjects.Length == 0)
        {
            Debug.LogWarning("请选择至少一个带 MeshRenderer 的物体！");
            return;
        }

        // 用于合批的 MeshCombineInstance 列表
        List<CombineInstance> combineInstances = new List<CombineInstance>();
        Material sharedMaterial = null;

        foreach (GameObject obj in selectedObjects)
        {
            MeshFilter mf = obj.GetComponent<MeshFilter>();
            MeshRenderer mr = obj.GetComponent<MeshRenderer>();

            if (mf == null || mr == null)
                continue;

            if (sharedMaterial == null)
                sharedMaterial = mr.sharedMaterial;

            if (mr.sharedMaterial != sharedMaterial)
            {
                Debug.LogWarning("存在不同材质的物体，合并后只保留第一种材质！");
            }

            CombineInstance ci = new CombineInstance();
            ci.mesh = mf.sharedMesh;
            ci.transform = obj.transform.localToWorldMatrix;
            combineInstances.Add(ci);
        }

        if (combineInstances.Count == 0)
        {
            Debug.LogWarning("未找到可合并的 Mesh！");
            return;
        }

        // 创建新 Mesh
        Mesh combinedMesh = new Mesh();
        combinedMesh.CombineMeshes(combineInstances.ToArray());

        // 创建新 GameObject
        GameObject combinedObj = new GameObject("CombinedMesh");
        MeshFilter newMF = combinedObj.AddComponent<MeshFilter>();
        MeshRenderer newMR = combinedObj.AddComponent<MeshRenderer>();

        newMF.sharedMesh = combinedMesh;
        newMR.sharedMaterial = sharedMaterial;

        Debug.Log("合并完成，共合并 " + combineInstances.Count + " 个物体！");
    }
}