Unity Scene窗口编辑工具常用鼠标、键盘例子

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

[CustomEditor(typeof(ArtAnnotate))]
public class ArtAnnotateEditor : Editor {

    public const int MOUSE_BUTTON_LEFT = 0;

    public const int MOUSE_BUTTON_RIGHT = 1;


    void OnSceneGUI()
    {

        if (Event.current.type == EventType.MouseDrag) {

        }

        if (Event.current.type == EventType.MouseDown) {
            if (Event.current.button == MOUSE_BUTTON_LEFT) {
                //用发射射线来确定点击目标
                 // Event.current.mousePosition屏幕坐标，左上角是（0，0）右下角（camera.pixelWidth，camera.pixelHeight）

                 // 需要转换成摄像机可接受的屏幕坐标，左下角是（0，0，0）右上角是（camera.pixelWidth，camera.pixelHeight，0）

                // 当前屏幕坐标，左上角是（0，0）右下角（camera.pixelWidth，camera.pixelHeight）
                Vector2 mousePosition = Event.current.mousePosition;

                // Retina 屏幕需要拉伸值
                  float mult = 1;
                  #if UNITY_5_4_OR_NEWER
                    mult = EditorGUIUtility.pixelsPerPoint;
                  #endif

                // 转换成摄像机可接受的屏幕坐标，左下角是（0，0，0）右上角是（camera.pixelWidth，camera.pixelHeight，0）
                mousePosition.y = SceneView.currentDrawingSceneView.camera.pixelHeight - mousePosition.y * mult;
                mousePosition.x *= mult;
                //获取世界坐标
                SceneView.currentDrawingSceneView.camera.ScreenToWorldPoint(mousePosition);
            }
        }

        if (Event.current.type == EventType.MouseUp ){
            if (Event.current.button == MOUSE_BUTTON_LEFT) {
                //用发射射线来确定点击目标
            } else if (Event.current.button == MOUSE_BUTTON_RIGHT) {
                if ((Event.current.modifiers & EventModifiers.Control) != 0) {
                    //按下Ctrl键盘
                } else {
                    GenericMenu menu = new GenericMenu ();
                    menu.AddDisabledItem (new GUIContent ("Not Recommend"));
                    menu.AddItem (new GUIContent ("UnSelect"), aTarget.brushType == BrushType.UnSelect, callMethodUnSelect, null);
                    menu.AddSeparator ("");
                    menu.AddItem (new GUIContent ("Cancel"), aTarget.brushType == BrushType.None, callmethodCancel, null);
                    menu.ShowAsContext ();
                }
                //设置该事件被使用
                Event.current.Use ();

            } else {
                //Debug.Log ("Event.current.button");
            }
                
        }
    }

}


    //UnSelect
    void callMethodUnSelect(object obj){

    }

    //取消
    void callmethodCancel(object obj){

    }