ExtendTransform仿NGUI在Transfrom左边添加重置按钮

using UnityEngine;
using UnityEditor;

[CanEditMultipleObjects]
[CustomEditor(typeof(Transform), true)]
public class TransformInspector : Editor
{
	static public TransformInspector instance;

	SerializedProperty mPos;
	SerializedProperty mRot;
	SerializedProperty mScale;

	void OnEnable ()
	{
		instance = this;

		if (this)
		{
			try
			{
				var so = serializedObject;
				mPos = so.FindProperty("m_LocalPosition");
				mRot = so.FindProperty("m_LocalRotation");
				mScale = so.FindProperty("m_LocalScale");
			}
			catch { }
		}
	}

	void OnDestroy () { instance = null; }

	/// 

	/// Draw the inspector widget.
	/// 

	public override void OnInspectorGUI ()
	{
		EditorGUIUtility.labelWidth = 15f;

		serializedObject.Update();

		DrawPosition();
		DrawRotation();
		DrawScale();

		serializedObject.ApplyModifiedProperties();
	}

	void DrawPosition ()
	{
		GUILayout.BeginHorizontal();
		bool reset = GUILayout.Button("P", GUILayout.Width(20f));
		EditorGUILayout.PropertyField(mPos.FindPropertyRelative("x"));
		EditorGUILayout.PropertyField(mPos.FindPropertyRelative("y"));
		EditorGUILayout.PropertyField(mPos.FindPropertyRelative("z"));
		GUILayout.EndHorizontal();

		if (reset) mPos.vector3Value = Vector3.zero;
	}

	void DrawScale ()
	{
		GUILayout.BeginHorizontal();
		{
			bool reset = GUILayout.Button("S", GUILayout.Width(20f));

			EditorGUILayout.PropertyField(mScale.FindPropertyRelative("x"));
			EditorGUILayout.PropertyField(mScale.FindPropertyRelative("y"));
			EditorGUILayout.PropertyField(mScale.FindPropertyRelative("z"));

			if (reset) mScale.vector3Value = Vector3.one;
		}
		GUILayout.EndHorizontal();
	}

#region Rotation is ugly as hell... since there is no native support for quaternion property drawing
	enum Axes : int
	{
		None = 0,
		X = 1,
		Y = 2,
		Z = 4,
		All = 7,
	}

	Axes CheckDifference (Transform t, Vector3 original)
	{
		Vector3 next = t.localEulerAngles;

		Axes axes = Axes.None;

		if (Differs(next.x, original.x)) axes |= Axes.X;
		if (Differs(next.y, original.y)) axes |= Axes.Y;
		if (Differs(next.z, original.z)) axes |= Axes.Z;

		return axes;
	}

	Axes CheckDifference (SerializedProperty property)
	{
		Axes axes = Axes.None;

		if (property.hasMultipleDifferentValues)
		{
			Vector3 original = property.quaternionValue.eulerAngles;

			foreach (Object obj in serializedObject.targetObjects)
			{
				axes |= CheckDifference(obj as Transform, original);
				if (axes == Axes.All) break;
			}
		}
		return axes;
	}

	/// 

	/// Draw an editable float field.
	/// 
	/// Whether to replace the value with a dash
	/// Whether the value should be greyed out or not

	static bool FloatField (string name, ref float value, bool hidden, GUILayoutOption opt)
	{
		float newValue = value;
		GUI.changed = false;

		if (!hidden)
		{
			newValue = EditorGUILayout.FloatField(name, newValue, opt);
		}
		else
		{
			float.TryParse(EditorGUILayout.TextField(name, "--", opt), out newValue);
		}

		if (GUI.changed && Differs(newValue, value))
		{
			value = newValue;
			return true;
		}
		return false;
	}

	/// 

	/// Because Mathf.Approximately is too sensitive.
	/// 

	static bool Differs (float a, float b) { return Mathf.Abs(a - b) > 0.0001f; }

	static public void RegisterUndo (string name, params Object[] objects)
	{
		if (objects != null && objects.Length > 0)
		{
			UnityEditor.Undo.RecordObjects(objects, name);

			foreach (Object obj in objects)
			{
				if (obj == null) continue;
				EditorUtility.SetDirty(obj);
			}
		}
	}

	static public float WrapAngle (float angle)
	{
		while (angle > 180f) angle -= 360f;
		while (angle < -180f) angle += 360f;
		return angle;
	}

	void DrawRotation ()
	{
		GUILayout.BeginHorizontal();
		{
			bool reset = GUILayout.Button("R", GUILayout.Width(20f));

			Vector3 visible = (serializedObject.targetObject as Transform).localEulerAngles;

			visible.x = WrapAngle(visible.x);
			visible.y = WrapAngle(visible.y);
			visible.z = WrapAngle(visible.z);

			Axes changed = CheckDifference(mRot);
			Axes altered = Axes.None;

			GUILayoutOption opt = GUILayout.MinWidth(30f);

			if (FloatField("X", ref visible.x, (changed & Axes.X) != 0, opt)) altered |= Axes.X;
			if (FloatField("Y", ref visible.y, (changed & Axes.Y) != 0, opt)) altered |= Axes.Y;
			if (FloatField("Z", ref visible.z, (changed & Axes.Z) != 0, opt)) altered |= Axes.Z;

			if (reset)
			{
				mRot.quaternionValue = Quaternion.identity;
			}
			else if (altered != Axes.None)
			{
				RegisterUndo("Change Rotation", serializedObject.targetObjects);

				foreach (Object obj in serializedObject.targetObjects)
				{
					Transform t = obj as Transform;
					Vector3 v = t.localEulerAngles;

					if ((altered & Axes.X) != 0) v.x = visible.x;
					if ((altered & Axes.Y) != 0) v.y = visible.y;
					if ((altered & Axes.Z) != 0) v.z = visible.z;

					t.localEulerAngles = v;
				}
			}
		}
		GUILayout.EndHorizontal();
	}
#endregion
}