unity, editable mesh
一，需求
从fbx载入的模型是不可以在unity里编辑的。
我有一人特殊的需求就是想在unity里为mesh的各顶点K动画。
于是需要自己实现一个可编辑（其实只是顶点可以拖动）的mesh。
二，思路
首先由导入的mesh复制一个新mesh，并将原mesh替换掉，这样是为了以后编辑过程不会破坏原mesh，然后就没有原mesh的事儿了。
假设mesh是一个立方体，则其mesh.vertices会有36个元素，mesh.triangles有12个元素。
我们要创建8个gameObject表示立方体的8个顶点gameObject，并根据mesh.vertices的坐标值设定顶点gameObject的localPosition（注意是localPosition而不是position），并且还要找出各顶点gameObject对象mesh.vertcies中的哪些元素。因为一共有8个顶点gameObject，但mesh.vertices有36个元素，所以一个gameObject对应多个元素。
三，unity里实现
1，创建一个gameObject，命句为editableMesh，并添加Mesh Filter和Mesh Renderer，Mesh Filter中添加模型mesh（例如从3dmax或blender中导出的模型）。
2，为editableMesh节点添加子节点vertexObjTemplate并将勾去掉使其变成Active==false状态，其上挂脚本vertexobjControl.cs:
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
public class vertexObjControl : MonoBehaviour {
public List<int> m_vIDList=new List<int>();
}
3，为editableMesh节点添加脚本convertmeshToEditableMesh.cs
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using UnityEngine.Assertions.Must;
[ExecuteInEditMode]
public class convertMeshToEditableMesh : MonoBehaviour {
private GameObject m_vertexObjs;
private GameObject m_vertexObjTemplate;
void Awake(){
m_vertexObjTemplate=transform.FindChild("vertexObjTemplate").gameObject;
CreateReplaceMeshFromOriginMesh ();
}
void Update(){
updateMeshVertex ();
}
void updateMeshVertex(){
int vertexCount = gameObject.GetComponent<MeshFilter> ().sharedMesh.vertexCount;
Vector3[] vertices = new Vector3[vertexCount] ;
int vertexObjCount = m_vertexObjs.transform.childCount;
for (int i=0; i<vertexObjCount; i++) {
GameObject vobj=m_vertexObjs.transform.GetChild(i).gameObject;
Vector3 vobjPos=vobj.transform.localPosition;
int nVID=vobj.GetComponent<vertexObjControl>().m_vIDList.Count;
for(int j=0;j<nVID;j++){
int vID=vobj.GetComponent<vertexObjControl>().m_vIDList[j];
vertices[vID]=vobjPos;
}
}
gameObject.GetComponent<MeshFilter> ().sharedMesh.vertices = vertices;
gameObject.GetComponent<MeshFilter> ().sharedMesh.RecalculateNormals();
gameObject.GetComponent<MeshFilter> ().sharedMesh.RecalculateBounds();
}
void CreateReplaceMeshFromOriginMesh()
{
//if vertexObjs is not created, create it
Transform vertexObjsTransform=transform.FindChild("vertexObjs");
if (vertexObjsTransform == null) {
m_vertexObjs = new GameObject ();
m_vertexObjs.name = "vertexObjs";
m_vertexObjs.transform.SetParent (gameObject.transform);
} else {
m_vertexObjs=vertexObjsTransform.gameObject;
}
//if mesh not replaced, replace it
if (gameObject.GetComponent<MeshFilter> ().sharedMesh.name != "replaceMesh") {
Mesh replaceMesh = Instantiate (gameObject.GetComponent<MeshFilter> ().sharedMesh) as Mesh;
replaceMesh.name = "replaceMesh";
gameObject.GetComponent<MeshFilter> ().sharedMesh = replaceMesh;
}
//if vobjs not generated, generate vobjs from replaved mesh
if (m_vertexObjs.transform.childCount == 0) {
int vertexCount = gameObject.GetComponent<MeshFilter> ().sharedMesh.vertexCount;
List<bool> list_isVIDHasAddedToVObj = new List<bool> ();
for (int i=0; i<vertexCount; i++) {
list_isVIDHasAddedToVObj.Add (false);
}
for (int vID=0; vID<vertexCount; vID++) {
if (list_isVIDHasAddedToVObj [vID]) {
continue;
}
//add vID of current vertex to existing vertexObj
Vector3 vPos = gameObject.GetComponent<MeshFilter> ().sharedMesh.vertices [vID];
int vertexObjCount = m_vertexObjs.transform.childCount;
for (int vobjID=0; vobjID<vertexObjCount; vobjID++) {
GameObject vobj = m_vertexObjs.transform.GetChild (vobjID).gameObject;
Vector3 vobjPos = vobj.transform.localPosition;
if (vPos == vobjPos) {
//add vID to vobj
vobj.GetComponent<vertexObjControl> ().m_vIDList.Add (vID);
list_isVIDHasAddedToVObj [vID] = true;
}
}
if (list_isVIDHasAddedToVObj [vID]) {//vID has added to existing vobj
//do nothing
} else {//no existing vobj for vID to add to
//create new vobj, and add vID to it
GameObject vobj = Instantiate (m_vertexObjTemplate);
vobj.SetActive (true);
vobj.name = "vobj_" + m_vertexObjs.transform.childCount;
vobj.transform.SetParent (m_vertexObjs.transform);
vobj.transform.localPosition = vPos;
vobj.GetComponent<vertexObjControl> ().m_vIDList.Add (vID);
list_isVIDHasAddedToVObj [vID] = true;
}
}
}
gameObject.GetComponent<MeshFilter> ().sharedMesh.RecalculateNormals();
gameObject.GetComponent<MeshFilter> ().sharedMesh.RecalculateBounds();
}
}
然后就可以在编辑器里移动mesh的顶点或给顶点K动画了。
----补充：
以上是通用的代码，可将任何mesh转成可编辑（只是移动顶点）的。
如果只想做一个可编辑的四边形面片，可以像下面这样简单实现：
1，创建一个gameObject命名为editableQuad。为editableQuad创建子节点vertexObjs。再为vertexObjs依次创建子节点vertexObj_0,vertexObj_1,vertexObj_2,vertexObj_3（按顺序排列）。
2，再为editableQuad添加脚本editableQuadControl.cs:
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using UnityEngine.Assertions.Must;
[ExecuteInEditMode]
public class editableQuadControl : MonoBehaviour {
private GameObject vertexObjs;
void Awake(){
vertexObjs=transform.FindChild("vertexObjs").gameObject;
int childCount = vertexObjs.transform.childCount;
int n = 4;
for (int i=0; i<n; i++) {
if(i>=childCount){
GameObject vertexObj=new GameObject ();
vertexObj.name="vertexObj_"+i;
vertexObj.transform.SetParent(vertexObjs.transform);
vertexObj.transform.localPosition=Random.insideUnitSphere;
}
}
gameObject.GetComponent<MeshFilter> ().mesh = CreateMesh ();
}
void Update(){
updateMeshVertex ();
}
void updateMeshVertex(){
Vector3 vLU = vertexObjs.transform.GetChild(0).localPosition;
Vector3 vLD = vertexObjs.transform.GetChild(1).localPosition;
Vector3 vRU = vertexObjs.transform.GetChild(2).localPosition;
Vector3 vRD = vertexObjs.transform.GetChild(3).localPosition;
gameObject.GetComponent<MeshFilter> ().sharedMesh.vertices = new Vector3[]{vLD,vLU,vRU,vRD};
}
Mesh CreateMesh()
{
Mesh m = new Mesh();
m.name = "ScriptedMesh";
//note: unity is left-hand system
Vector3 vLU = vertexObjs.transform.GetChild(0).localPosition;
Vector3 vLD = vertexObjs.transform.GetChild(1).localPosition;
Vector3 vRU = vertexObjs.transform.GetChild(2).localPosition;
Vector3 vRD = vertexObjs.transform.GetChild(3).localPosition;
m.vertices = new Vector3[] {
vLD,//LD
vLU,//LU
vRU,//RU
vRD//RD
};
m.uv = new Vector2[] {
new Vector2 (0, 0),
new Vector2 (0, 1),
new Vector2 (1, 1),
new Vector2 (1, 0)
};
m.triangles = new int[] { 0, 1, 2, 0, 2, 3};
m.RecalculateNormals();
m.RecalculateBounds();
return m;
}
}
