父Prefab与子prefab问题

PrefabRevolution

原文：http://framebunker.com/blog/poor-mans-nested-prefabs/   （溜还是老外溜啊）

有些时候需要在Prefab里预制一个子prefab，但unity只会默认父prefab，一旦预制了prefab就会与其内部的prefab失去关联；

using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;
using UnityEditor.Callbacks;
#endif
using System.Collections.Generic;
 
[ExecuteInEditMode]
public class PrefabInstance : MonoBehaviour
{
public GameObject prefab;
 
#if UNITY_EDITOR
// Struct of all components. Used for edit-time visualization and gizmo drawing
public struct Thingy {
public Mesh mesh;
public Matrix4x4 matrix;
public List<Material> materials;
}
 
[System.NonSerializedAttribute] public List<Thingy> things = new List<Thingy> ();
 
void OnValidate () {
things.Clear();
if (enabled)
Rebuild (prefab, Matrix4x4.identity);
}
 
void OnEnable () {
things.Clear();
if (enabled)
Rebuild (prefab, Matrix4x4.identity);
}
 
void Rebuild (GameObject source, Matrix4x4 inMatrix) {
if (!source)
return;
 
Matrix4x4 baseMat = inMatrix * Matrix4x4.TRS (-source.transform.position, Quaternion.identity, Vector3.one);

foreach (MeshRenderer mr in source.GetComponentsInChildren(typeof (Renderer), true))
{
things.Add(new Thingy () {
mesh = mr.GetComponent<MeshFilter>().sharedMesh,
matrix = baseMat * mr.transform.localToWorldMatrix,
materials = new List<Material> (mr.sharedMaterials)
});
}
 
foreach (PrefabInstance pi in source.GetComponentsInChildren(typeof (PrefabInstance), true))
{
if (pi.enabled && pi.gameObject.activeSelf)
Rebuild (pi.prefab, baseMat * pi.transform.localToWorldMatrix);
}
}
 
// Editor-time-only update: Draw the meshes so we can see the objects in the scene view
void Update () {
if (EditorApplication.isPlaying)
return;
Matrix4x4 mat = transform.localToWorldMatrix;
foreach (Thingy t in things)
for (int i = 0; i < t.materials.Count; i++)
Graphics.DrawMesh (t.mesh, mat * t.matrix, t.materials[i], gameObject.layer, null, i);
}
 
// Picking logic: Since we don't have gizmos.drawmesh, draw a bounding cube around each thingy
void OnDrawGizmos () { DrawGizmos (new Color (0,0,0,0)); }
void OnDrawGizmosSelected () { DrawGizmos (new Color (0,0,1,.2f)); }
void DrawGizmos (Color col) {
if (EditorApplication.isPlaying)
return;
Gizmos.color = col;
Matrix4x4 mat = transform.localToWorldMatrix;
foreach (Thingy t in things)
{
Gizmos.matrix = mat * t.matrix;
Gizmos.DrawCube(t.mesh.bounds.center, t.mesh.bounds.size);
}
}
 
// Baking stuff: Copy in all the referenced objects into the scene on play or build
[PostProcessScene(-2)]
public static void OnPostprocessScene() { 
foreach (PrefabInstance pi in UnityEngine.Object.FindObjectsOfType (typeof (PrefabInstance)))
    BakeInstance (pi);
}
 
public static void BakeInstance (PrefabInstance pi) {
if(!pi.prefab || !pi.enabled)
return;
pi.enabled = false;
GameObject go = PrefabUtility.InstantiatePrefab(pi.prefab) as GameObject;
Quaternion rot = go.transform.localRotation;
Vector3 scale = go.transform.localScale;
go.transform.parent = pi.transform;
go.transform.localPosition = Vector3.zero;
go.transform.localScale = scale;
go.transform.localRotation = rot;
pi.prefab = null;
foreach (PrefabInstance childPi in go.GetComponentsInChildren<PrefabInstance>())
BakeInstance (childPi);
}
 
#endif
}

PrefabInstance 类能解决这个问题，用法：比如有两个prefab，PrefabFarent和PrefabSon,只需要把PrefabInstance 类挂到PrefabFarent上，把PrefabSon拖到prefab里就行。

这样无论怎么改变PrefabSon，当实例化PrefabFarent时都能得到最新改变了的PrefabSon