MeshCombiner.cs

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

#if UNITY_EDITOR
using UnityEditor;
#endif

[ExecuteInEditMode]
public class MeshCombiner : MonoBehaviour {
	
	#if UNITY_EDITOR
	
	
	public GameObject generatedObject = null;
	
	[ContextMenu("Export")]
	void Init ()
	{
		Component[] meshFilters = GetComponentsInChildren<MeshFilter>(true);
		Dictionary<Material, List<CombineInstance>> combineMeshInstanceDictionary = new Dictionary<Material, List<CombineInstance>> ();

		foreach (var mesh in meshFilters) {
			
			var mat = mesh.renderer.sharedMaterial ;
			
			if( mat == null )
				continue;
			
			if(!combineMeshInstanceDictionary.ContainsKey(mat) )
			{
				combineMeshInstanceDictionary.Add( mat, new List<CombineInstance>());
			}
			var instance = combineMeshInstanceDictionary[ mat ];
			var cmesh = new CombineInstance();
			cmesh.transform = mesh.transform.localToWorldMatrix;
			cmesh.mesh = ((MeshFilter) mesh).sharedMesh;
			instance.Add(cmesh);
		}
		
		gameObject.SetActive (false);
		gameObject.tag = "EditorOnly";
		
		
		if( generatedObject == null)
			generatedObject = new GameObject (name);

		foreach (var item in generatedObject.GetComponentsInChildren<Transform>()) {
			if( item == generatedObject.transform )
				continue;
			
			DestroyImmediate (item.gameObject);
		}
		
		generatedObject.isStatic = true;
		
		foreach (var dic in combineMeshInstanceDictionary) {
			
			var newObject = new GameObject(dic.Key.name);
			newObject.isStatic = true;
			
			var meshrenderer = newObject.AddComponent<MeshRenderer>();
			var meshfilter = newObject.AddComponent<MeshFilter>();
			
			meshrenderer.material = dic.Key;
			var mesh = new Mesh();
			mesh.CombineMeshes(dic.Value.ToArray());
			Unwrapping.GenerateSecondaryUVSet( mesh);
			meshfilter.sharedMesh = mesh;
			newObject.transform.parent = generatedObject.transform;

			Debug.Log(Application.loadedLevelName);
			System.IO.Directory.CreateDirectory( "Assets/" + Application.loadedLevelName + "/" + name );
			AssetDatabase.CreateAsset(mesh, "Assets/" + Application.loadedLevelName+ "/" + name + "/" + dic.Key.name + ".asset");
		}
	}
	
	void OnEnable()
	{
		if (generatedObject != null) {
			generatedObject.SetActive(false);
		}
	}
	
	void OnDisable()
	{
		if (generatedObject != null) {
			generatedObject.SetActive(true);
		}
	}
	#endif
}