Unity3D之Editor扩展学习——四大名捕闹京东

        Unity3D提供了强大的编辑器扩展机制，在项目开发中，如果可以将一些繁琐的工作放在编辑器扩展中进行，则会大大提高效率。本文对编辑器扩展进行了一些总结，希望对有兴趣编写编辑器扩展的开发人员有所帮助。当我们编写一个编辑器扩展时，一般可以从以下四个类继承：

ScriptableObject

最常见的小功能扩展，一般不用窗口的编辑扩展，可以从这个类中继承，如以下代码所示：

using UnityEngine;
using UnityEditor;
using System.Collections;

public class AddChild : ScriptableObject
{
[MenuItem ("GameObject/Add Child ^n")]
static void MenuAddChild()
{
Transform[] transforms = Selection.GetTransforms(SelectionMode.TopLevel | SelectionMode.OnlyUserModifiable);

foreach(Transform transform in transforms)
{
GameObject newChild = new GameObject("_Child");
newChild.transform.parent = transform;
}
}
}
这个扩展脚本从菜单的“GameObject->Add Child”启动，功能是给Hierarchy窗口中选中的对GameObject添加一个名字为“_Child”的子GameObject，这样可以免去从Hierarchy窗口的根节点拖拽新创建的GameObject到当前选中节点的麻烦，因为在Unity3D编辑器中，创建一个EmptyObject会在Hierarchy窗口的根节点出现，无论当前选中的节点对象是哪个。

ScriptableWizard

需要对扩展的参数进行设置，然后再进行功能触发的，可以从这个类进行派生。它已经定制好了四个消息响应函数，开发者对其进行填充即可。

(1) OnWizardUpdate  

当扩展窗口打开时或用户对窗口的内容进行改动时，会调用此函数。一般会在这里面显示帮助文字和进行内容有效性验证；

(2)OnWizardCreate
 

这是用户点击窗口的Create按钮时进行的操作，从ScriptableWizard的名字可以看出，这是一种类似向导的窗口，只不过Unity3D中的ScriptableWizard窗口只能进行小于或等于两个按钮的定制，一个就是所谓的Create按钮，另外一个则笼统称之为Other按钮。ScriptableWizard.DisplayWizard这个静态函数用于对ScriptableWizard窗口标题和按钮名字的定制；

(3) OnDrawGizmos
在窗口可见时，每一帧都会调用这个函数。在其中进行Gizmos的绘制，也就是辅助编辑的线框体。Unity的Gizmos类提供了DrawRayDrawLine ,DrawWireSphere ,DrawSphere ,DrawWireCube
,DrawCubeDrawIcon ,DrawGUITexture 功能。这个功能在Unity3D 的3.4版本中测试了一下，发现没有任何Gizmos绘制出来


(4) OnWizardOtherButton
本文在(2) 中已经提及，ScriptableWizard窗口最多可以定制两个按钮，一个是Create，另外一个称之为Other，这个函数会在other按钮被点击时调用。下面是一个使用ScriptableWizard进行编辑扩展的例子：

using UnityEditor;
using UnityEngine;
using System.Collections;

/// <summary>
/// 对于选定GameObject，进行指定component的批量添加
/// </summary>
public class AddRemoveComponentsRecursively : ScriptableWizard
{
public string componentType = null;

/// <summary>
/// 当没有任何GameObject被选中的时候，将菜单disable（注意，这个函数名可以随意取）
/// </summary>
/// <returns></returns>
[MenuItem("GameObject/Add or remove components recursively...", true)]
static bool CreateWindowDisabled()
{
return Selection.activeTransform;
}

/// <summary>
/// 创建编辑窗口（注意，这个函数名可以随意取）
/// </summary>
[MenuItem("GameObject/Add or remove components recursively...")]
static void CreateWindow()
{
// 定制窗口标题和按钮，其中第二个参数是Create按钮，第三个则属于other按钮
// 如果不想使用other按钮，则可调用DisplayWizard的两参数版本
ScriptableWizard.DisplayWizard<AddRemoveComponentsRecursively>(
"Add or remove components recursivly",
"Add", "Remove");
}

/// <summary>
/// 窗口创建或窗口内容更改时调用
/// </summary>
void OnWizardUpdate()
{
helpString = "Note: Duplicates are not created";

if (string.IsNullOrEmpty(componentType))
{
errorString = "Please enter component class name";
isValid = false;
}
else
{
errorString = "";
isValid = true;
}
}

/// <summary>
/// 点击Add按钮（即Create按钮）调用
/// </summary>
void OnWizardCreate()
{
int c = 0;
Transform[] ts = Selection.GetTransforms(SelectionMode.Deep);
foreach (Transform t in ts)
{
if (t.gameObject.GetComponent(componen
11e86
tType) == null)
{
if (t.gameObject.AddComponent(componentType) == null)
{
Debug.LogWarning("Component of type " + componentType + " does not exist");
return;
}
c++;
}
}
Debug.Log("Added " + c + " components of type " + componentType);
}

/// <summary>
/// 点击Remove（即other按钮）调用
/// </summary>
void OnWizardOtherButton()
{
int c = 0;
Transform[] ts = Selection.GetTransforms(SelectionMode.Deep);
foreach (Transform t in ts)
{
if (t.GetComponent(componentType) != null)
{
DestroyImmediate(t.GetComponent(componentType));
c++;
}
}
Debug.Log("Removed " + c + " components of type " + componentType);
Close();
}
}

EditorWindow

较复杂的功能，需要多个灵活的控件，实现自由浮动和加入其他窗口的tab，可以从这个类派生，这种窗口的窗体功能和Scene，Hierarchy等窗口完全一致。下面这个例子实现了GameObject的空间对齐和拷贝（也就是将GameObject
A作为基准，选中其他的GameObject进行对准或空间位置拷贝），对齐和拷贝提高了了开发者摆放物件的效率；另外还有随机和噪声，后两者用于摆放大量同类物件的时候可以使用，比如一大堆散落的瓶子。

// /////////////////////////////////////////////////////////////////////////////////////////////////////////
//
// Transform Utilities.
//
// This window contains four useful tools for asset placing and manipulation: Align, Copy, Randomize and Add noise.
//
// Put this into Assets/Editor and once compiled by Unity you find
// the new functionality in Window -> TransformUtilities, or simply press Ctrl+t (Cmd+t for Mac users)
//
// Developed by Daniel
// http://www.silentkraken.com // e-mail: seth@silentkraken.com
//
// /////////////////////////////////////////////////////////////////////////////////////////////////////////

using UnityEngine;
using UnityEditor;

public class TransformUtilitiesWindow : EditorWindow
{
//Window control values
public int toolbarOption = 0;
public string[] toolbarTexts = {"Align", "Copy", "Randomize", "Add noise"};

private bool xCheckbox = true;
private bool yCheckbox = true;
private bool zCheckbox = true;

private Transform source;
private float randomRangeMin = 0f;
private float randomRangeMax = 1f;
private int alignSelectionOption = 0;
private int alignSourceOption = 0;

/// <summary>
/// Retrives the TransformUtilities window or creates a new one
/// </summary>
[MenuItem("Window/TransformUtilities %t")]
static void Init()
{
TransformUtilitiesWindow window = (TransformUtilitiesWindow)EditorWindow.GetWindow(typeof(TransformUtilitiesWindow));
window.Show();
}

/// <summary>
/// Window drawing operations
/// </summary>
void OnGUI ()
{
toolbarOption = GUILayout.Toolbar(toolbarOption, toolbarTexts);
switch (toolbarOption)
{
case 0:
CreateAxisCheckboxes("Align");
CreateAlignTransformWindow();
break;
case 1:
CreateAxisCheckboxes("Copy");
CreateCopyTransformWindow();
break;
case 2:
CreateAxisCheckboxes("Randomize");
CreateRandomizeTransformWindow();
break;
case 3:
CreateAxisCheckboxes("Add noise");
CreateAddNoiseToTransformWindow();
break;
}
}

/// <summary>
/// Draws the 3 axis checkboxes (x y z)
/// </summary>
/// <param name="operationName"></param>
private void CreateAxisCheckboxes(string operationName)
{
GUILayout.Label(operationName + " on axis", EditorStyles.boldLabel);

GUILayout.BeginHorizontal();
xCheckbox = GUILayout.Toggle(xCheckbox, "X");
yCheckbox = GUILayout.Toggle(yCheckbox, "Y");
zCheckbox = GUILayout.Toggle(zCheckbox, "Z");
GUILayout.EndHorizontal();

EditorGUILayout.Space();
}

/// <summary>
/// Draws the range min and max fields
/// </summary>
private void CreateRangeFields()
{
GUILayout.Label("Range", EditorStyles.boldLabel);
GUILayout.BeginHorizontal();
randomRangeMin = EditorGUILayout.FloatField("Min:", randomRangeMin);
randomRangeMax = EditorGUILayout.FloatField("Max:", randomRangeMax);
GUILayout.EndHorizontal();
EditorGUILayout.Space();
}

/// <summary>
/// Creates the Align transform window
/// </summary>
private void CreateAlignTransformWindow()
{
//Source transform
GUILayout.BeginHorizontal();
GUILayout.Label("Align to: \t");
source = EditorGUILayout.ObjectField(source, typeof(Transform)) as Transform;
GUILayout.EndHorizontal();

string[] texts = new string[4] { "Min", "Max", "Center", "Pivot" };

//Display align options
EditorGUILayout.BeginHorizontal();
EditorGUILayout.BeginVertical();
GUILayout.Label("Selection:", EditorStyles.boldLabel);
alignSelectionOption = GUILayout.SelectionGrid(alignSelectionOption, texts, 1);
EditorGUILayout.EndVertical();
EditorGUILayout.BeginVertical();
GUILayout.Label("Source:", EditorStyles.boldLabel);
alignSourceOption = GUILayout.SelectionGrid(alignSourceOption, texts, 1);
EditorGUILayout.EndVertical();
EditorGUILayout.EndHorizontal();

EditorGUILayout.Space();

//Position
if (GUILayout.Button("Align"))
{
if (source != null)
{
//Add a temporary box collider to the source if it doesn't have one
Collider sourceCollider = source.collider;
bool destroySourceCollider = false;
if (sourceCollider == null)
{
sourceCollider = source.gameObject.AddComponent<BoxCollider>();
destroySourceCollider = true;
}

foreach (Transform t in Selection.transforms)
{
//Add a temporary box collider to the transform if it doesn't have one
Collider transformCollider = t.collider;
bool destroyTransformCollider = false;
if (transformCollider == null)
{
transformCollider = t.gameObject.AddComponent<BoxCollider>();
destroyTransformCollider = true;
}

Vector3 sourceAlignData = new Vector3();
Vector3 transformAlignData = new Vector3();

//Transform
switch (alignSelectionOption)
{
case 0: //Min
transformAlignData = transformCollider.bounds.min;
break;
case 1: //Max
transformAlignData = transformCollider.bounds.max;
break;
case 2: //Center
transformAlignData = transformCollider.bounds.center;
break;
case 3: //Pivot
transformAlignData = transformCollider.transform.position;
break;
}

//Source
switch (alignSourceOption)
{
case 0: //Min
sourceAlignData = sourceCollider.bounds.min;
break;
case 1: //Max
sourceAlignData = sourceCollider.bounds.max;
break;
case 2: //Center
sourceAlignData = sourceCollider.bounds.center;
break;
case 3: //Pivot
sourceAlignData = sourceCollider.transform.position;
break;
}

Vector3 tmp = new Vector3();
tmp.x = xCheckbox ? sourceAlignData.x - (transformAlignData.x - t.position.x) : t.position.x;
tmp.y = yCheckbox ? sourceAlignData.y - (transformAlignData.y - t.position.y) : t.position.y;
tmp.z = zCheckbox ? sourceAlignData.z - (transformAlignData.z - t.position.z) : t.position.z;

//Register the Undo
Undo.RegisterUndo(t, "Align " + t.gameObject.name + " to " + source.gameObject.name);
t.position = tmp;

//Ugly hack!
//Unity needs to update the collider of the selection to it's new position
//(it stores in cache the collider data)
//We can force the update by a change in a public variable (shown in the inspector),
//then a call SetDirty to update the collider (it won't work if all inspector variables are the same).
//But we want to restore the changed property to what it was so we do it twice.
transformCollider.isTrigger = !transformCollider.isTrigger;
EditorUtility.SetDirty(transformCollider);
transformCollider.isTrigger = !transformCollider.isTrigger;
EditorUtility.SetDirty(transformCollider);

//Destroy the collider we added
if (destroyTransformCollider)
{
DestroyImmediate(transformCollider);
}
}

//Destroy the collider we added
if (destroySourceCollider)
{
DestroyImmediate(sourceCollider);
}
}
else
{
EditorUtility.DisplayDialog("Error", "There is no source transform", "Ok");
EditorApplication.Beep();
}
}
}

/// <summary>
/// Creates the copy transform window
/// </summary>
private void CreateCopyTransformWindow()
{
//Source transform
GUILayout.BeginHorizontal();
GUILayout.Label("Copy from: \t");
source = EditorGUILayout.ObjectField(source, typeof(Transform)) as Transform;
GUILayout.EndHorizontal();

EditorGUILayout.Space();

//Position
if (GUILayout.Button("Copy Position"))
{
if (source != null)
{
foreach (Transform t in Selection.transforms)
{
Vector3 tmp = new Vector3();
tmp.x = xCheckbox ? source.position.x : t.position.x;
tmp.y = yCheckbox ? source.position.y : t.position.y;
tmp.z = zCheckbox ? source.position.z : t.position.z;

Undo.RegisterUndo(t, "Copy position");
t.position = tmp;
}
}
else
{
EditorUtility.DisplayDialog("Error", "There is no source transform", "Ok");
EditorApplication.Beep();
}
}

//Rotation
if (GUILayout.Button("Copy Rotation"))
{
if (source != null)
{
foreach (Transform t in Selection.transforms)
{
Vector3 tmp = new Vector3();
tmp.x = xCheckbox ? source.rotation.eulerAngles.x : t.rotation.eulerAngles.x;
tmp.y = yCheckbox ? source.rotation.eulerAngles.y : t.rotation.eulerAngles.y;
tmp.z = zCheckbox ? source.rotation.eulerAngles.z : t.rotation.eulerAngles.z;
Quaternion tmp2 = t.rotation;
tmp2.eulerAngles = tmp;

Undo.RegisterUndo(t, "Copy rotation");
t.rotation = tmp2;
}
}
else
{
EditorUtility.DisplayDialog("Error", "There is no source transform", "Ok");
EditorApplication.Beep();
}
}

//Local Scale
if (GUILayout.Button("Copy Local Scale"))
{
if (source != null)
{
foreach (Transform t in Selection.transforms)
{
Vector3 tmp = new Vector3();
tmp.x = xCheckbox ? source.localScale.x : t.localScale.x;
tmp.y = yCheckbox ? source.localScale.y : t.localScale.y;
tmp.z = zCheckbox ? source.localScale.z : t.localScale.z;

Undo.RegisterUndo(t, "Copy local scale");
t.localScale = tmp;
}
}
else
{
EditorUtility.DisplayDialog("Error", "There is no source transform", "Ok");
EditorApplication.Beep();
}
}
}

/// <summary>
/// Creates the Randomize transform window
/// </summary>
private void CreateRandomizeTransformWindow()
{
CreateRangeFields();

//Position
if (GUILayout.Button("Randomize Position"))
{
foreach (Transform t in Selection.transforms)
{
Vector3 tmp = new Vector3();
tmp.x = xCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : t.position.x;
tmp.y = yCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : t.position.y;
tmp.z = zCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : t.position.z;

Undo.RegisterUndo(t, "Randomize position");
t.position = tmp;
}
}

//Rotation
if (GUILayout.Button("Randomize Rotation"))
{
foreach (Transform t in Selection.transforms)
{
Vector3 tmp = new Vector3();
tmp.x = xCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : t.rotation.eulerAngles.x;
tmp.y = yCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : t.rotation.eulerAngles.y;
tmp.z = zCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : t.rotation.eulerAngles.z;
Quaternion tmp2 = t.rotation;
tmp2.eulerAngles = tmp;

Undo.RegisterUndo(t, "Randomize rotation");
t.rotation = tmp2;
}
}

//Local Scale
if (GUILayout.Button("Randomize Local Scale"))
{
foreach (Transform t in Selection.transforms)
{
Vector3 tmp = new Vector3();
tmp.x = xCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : t.localScale.x;
tmp.y = yCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : t.localScale.y;
tmp.z = zCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : t.localScale.z;

Undo.RegisterUndo(t, "Randomize local scale");
t.localScale = tmp;
}
}
}

/// <summary>
/// Creates the Add Noise To Transform window
/// </summary>
private void CreateAddNoiseToTransformWindow()
{
CreateRangeFields();

//Position
if (GUILayout.Button("Add noise to Position"))
{
foreach (Transform t in Selection.transforms)
{
Vector3 tmp = new Vector3();
tmp.x = xCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : 0;
tmp.y = yCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : 0;
tmp.z = zCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : 0;

Undo.RegisterUndo(t, "Add noise to position");
t.position += tmp;
}
}

//Rotation
if (GUILayout.Button("Add noise to Rotation"))
{
foreach (Transform t in Selection.transforms)
{
Vector3 tmp = new Vector3();
tmp.x = xCheckbox ? t.rotation.eulerAngles.x + Random.Range(randomRangeMin, randomRangeMax) : 0;
tmp.y = yCheckbox ? t.rotation.eulerAngles.y + Random.Range(randomRangeMin, randomRangeMax) : 0;
tmp.z = zCheckbox ? t.rotation.eulerAngles.z + Random.Range(randomRangeMin, randomRangeMax) : 0;

Undo.RegisterUndo(t, "Add noise to rotation");
t.rotation = Quaternion.Euler(tmp);
}
}

//Local Scale
if (GUILayout.Button("Add noise to Local Scale"))
{
foreach (Transform t in Selection.transforms)
{
Vector3 tmp = new Vector3();
tmp.x = xCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : 0;
tmp.y = yCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : 0;
tmp.z = zCheckbox ? Random.Range(randomRangeMin, randomRangeMax) : 0;

Undo.RegisterUndo(t, "Add noise to local scale");
t.localScale += tmp;
}
}
}
}

Editor

对某自定义组件进行观察的Inspector窗口，可以从它派生。如下代码所示：

代码片段1定义了一个名为Star的组件：

using System;
using UnityEngine;

[RequireComponent(typeof(MeshFilter), typeof(MeshRenderer))]
public class Star : MonoBehaviour {

[Serializable]
public class Point {
public Color color;
public Vector3 offset;
}

public Point[] points;
public int frequency = 1;
public Color centerColor;

private Mesh mesh;
private Vector3[] vertices;
private Color[] colors;
private int[] triangles;

void Start () {
GetComponent<MeshFilter>().mesh = mesh = new Mesh();
mesh.name = "Star Mesh";

if(frequency < 1){
frequency = 1;
}
if(points == null || points.Length == 0){
points = new Point[]{ new Point()};
}

int numberOfPoints = frequency * points.Length;
vertices = new Vector3[numberOfPoints + 1];
colors = new Color[numberOfPoints + 1];
triangles = new int[numberOfPoints * 3];
float angle = -360f / numberOfPoints;
colors[0] = centerColor;
for(int iF = 0, v = 1, t = 1; iF < frequency; iF++){
for(int iP = 0; iP < points.Length; iP += 1, v += 1, t += 3){
vertices[v] = Quaternion.Euler(0f, 0f, angle * (v - 1)) * points[iP].offset;
colors[v] = points[iP].color;
triangles[t] = v;
triangles[t + 1] = v + 1;
}
}
triangles[triangles.Length - 1] = 1;

mesh.vertices = vertices;
mesh.colors = colors;
mesh.triangles = triangles;
}
}

代码片段2定义了对Star组件进行观测的Inspector窗口：
using UnityEditor;
using UnityEngine;

[CustomEditor(typeof(Star))]
public class StarInspector : Editor {

private static GUIContent
insertContent = new GUIContent("+", "duplicate this point"),
deleteContent = new GUIContent("-", "delete this point"),
pointContent = GUIContent.none;

private static GUILayoutOption
buttonWidth = GUILayout.MaxWidth(20f),
colorWidth = GUILayout.MaxWidth(50f);

private SerializedObject star;
private SerializedProperty
points,
frequency,
centerColor;

void OnEnable () { … }

public override void OnInspectorGUI () {
star.Update();

GUILayout.Label("Points");
for(int i = 0; i < points.arraySize; i++){
EditorGUILayout.BeginHorizontal();
SerializedProperty point = points.GetArrayElementAtIndex(i);
EditorGUILayout.PropertyField(point.FindPropertyRelative("offset"), pointContent);
EditorGUILayout.PropertyField(point.FindPropertyRelative("color"), pointContent, colorWidth);

if(GUILayout.Button(insertContent, EditorStyles.miniButtonLeft, buttonWidth)){
points.InsertArrayElementAtIndex(i);
}
if(GUILayout.Button(deleteContent, EditorStyles.miniButtonRight, buttonWidth)){
points.DeleteArrayElementAtIndex(i);
}

EditorGUILayout.EndHorizontal();
}

EditorGUILayout.PropertyField(frequency);
EditorGUILayout.PropertyField(centerColor);

star.ApplyModifiedProperties();
}
}
说到这里，大家对ScriptableObject, ScriptableWizard,
EditorWindow和Editor应该都有应有了一定了解。其中EditorWindow和Editor都继承了ScriptableObject，而ScritableWizard则继承了EditorWindow派。在实际开发应用中，应该根据需求的特点，灵活使用这四个类进行编辑器扩展。
参考资料：

1. http://catlikecoding.com/unity/tutorials/star/

2. http://www.unifycommunity.com/wiki

3. http://www.blog.silentkraken.com/2010/02/06/transformutilities/
4.http://unity3d.com/support/documentation/ScriptReference