编辑器Scene视图扩展 - Handles.Slider2D

效果

#if UNITY_EDITOR

using UnityEditor;
using UnityEngine;

public class TestSceneGUIWindow : EditorWindow
{
    [MenuItem("MyTools/TestSceneGUIWindow")]
    public static void ShowWindow()
    {
        EditorWindow.GetWindow<TestSceneGUIWindow>(false, "TestSceneGUIWindow", true).Show();
    }

    private Vector3 m_Position = new Vector3();

    private void OnEnable()
    {
        SceneView.onSceneGUIDelegate -= OnMySceneGUI;
        SceneView.onSceneGUIDelegate += OnMySceneGUI;
    }

    private void OnDisable()
    {
        SceneView.onSceneGUIDelegate -= OnMySceneGUI;
    }

    private void OnMySceneGUI(SceneView sceneView)
    {
        //在这边扩展Scene视图

        float handleSize = HandleUtility.GetHandleSize(m_Position);

        Handles.color = Color.yellow;
        var handleDir = new Vector3(1, 1, 1);
        //以handleDir为法线的平面, 在slider滑动平面上的投影区域, 为滑动块的可滑动区域
        ShowHelpPlane(handleDir);
        m_Position = Handles.Slider2D(m_Position, handleDir, Vector3.right, Vector3.up, handleSize, Handles.ArrowHandleCap, 0);

        ShowHelpLines();
    }

    private void ShowHelpPlane(Vector3 handleDir)
    {
        var planeGo = GameObject.Find("Plane");
        if (null != planeGo)
        {
            planeGo.transform.up = handleDir;
            planeGo.transform.position = m_Position;
        }
    }

    private void ShowHelpLines()
    {
        Handles.color = Color.cyan;
        Handles.DrawAAPolyLine(Vector3.zero, m_Position); //原点到Slider2D滑动块的连线

        Handles.color = Color.red;
        Handles.DrawAAPolyLine(Vector3.zero, new Vector3(20, 0, 0)); //x轴

        Handles.color = Color.green;
        Handles.DrawAAPolyLine(Vector3.zero, new Vector3(0, 20, 0)); //y轴

        Handles.color = Color.blue;
        Handles.DrawAAPolyLine(Vector3.zero, new Vector3(0, 0, 20)); //z轴
    }

}

#endif

把handleDir换成new Vector(0, 1, 0), 以handDir为法线的平面, 在slider滑动平面上的投影区域就是一条直线, 此时只能在这条直线范围上操作 

var handleDir = new Vector3(1, 0, 0);也是如此

这几个的投影区域都是x-y平面上的一块区域，都可以在x-y平面内无限制滑动
var handleDir = new Vector3(0, 0, 1);
var handleDir = new Vector3(1, 0, 1);
var handleDir = new Vector3(0, 1, 1);
var handleDir = new Vector3(1, 1, 1);