UnityEditorでNodeベースのエディターを作る。

CustomEditorWindow.cs

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


public class CustomEditorWindow : EditorWindow
{
    class NodeData
    {
        public Rect window;
        public string title;
        public string name;
        public float test;
        public string style;
        public List<NodeData> children = new List<NodeData>();
    }

    List<NodeData> list = new List<NodeData>();

    [MenuItem("Window/UnityPlayer")]
    static void Open()
    {
        var editor = EditorWindow.GetWindow<CustomEditorWindow>();
        editor.Init();
    }

    void Init()
    {
        var w1 = new NodeData();
        w1.window = new Rect(10, 10, 300, 100);
        w1.title = "Title";
        w1.name = "name1";
        var w2 = new NodeData();
        w2.title = "Title2";
        w2.name = "name2";
        w2.style = "flow node 1";
        w2.window = new Rect(210, 210, 300, 100);
        w1.children.Add(w2);
        list.Add(w1);
        list.Add(w2);
    }

    public void OnGUI()
    {
        // Nodeをつなげる
        list.Where(e => e.children.Count > 0).ToList().ForEach(_ =>
            {
                _.children.ForEach(v => DrawNodeCurve(_.window, v.window));
            });
        OnRightClick();
        BeginWindows();
        for (var i = 0; i < list.Count; i++)
        {
            var n = list[i];
            if (string.IsNullOrEmpty(n.style))
            {
                n.window = GUI.Window(i, n.window, DrawNodeWindow, n.title);//, "flow node 5");
            }
            else
            {
                n.window = GUI.Window(i, n.window, DrawNodeWindow, n.title, n.style);//, "flow node 5");
            }
        }
        EndWindows();
    }

    void OnRightClick()
    {
        var evt = Event.current;
        if (evt.type == EventType.ContextClick)
        {
            var pos = evt.mousePosition;
            GenericMenu menu = new GenericMenu();
            menu.AddItem(new GUIContent("Create Node"), false, (obj) =>
                {
                    CreateNode((Vector2)obj, "Title", "test");
                }, pos);
            menu.ShowAsContext();
            evt.Use();
        }
        if (evt.type == EventType.MouseDown && evt.button == 1)
        {
            var pos = evt.mousePosition;
            GenericMenu menu = new GenericMenu();
            var index = list.FindIndex(_ => _.window.Contains(pos));
            if (index >= 0)
            {
                menu.AddItem(new GUIContent("Delete Node"), false, (obj) =>
                    {
                        list.RemoveAt(index);
                    }, pos);
            }
            menu.ShowAsContext();
            evt.Use();
        }
    }

    void DrawNodeWindow(int id)
    {
        EditorGUILayout.LabelField(list[id].name);
        list[id].test = EditorGUILayout.Slider("test", list[id].test, 0, 100);
        GUI.DragWindow();
    }

    void DrawNodeCurve(Rect start, Rect end)
    {
        Vector3 startPos = new Vector3(start.x + start.width, start.y + start.height / 2, 0);
        Vector3 endPos = new Vector3(end.x, end.y + end.height / 2, 0);
        Vector3 startTan = startPos + Vector3.right * 50;
        Vector3 endTan = endPos + Vector3.left * 50;
        Color shadowCol = new Color(0, 0, 0, 0.06f);
        for (int i = 0; i < 3; i++) // Draw a shadow
            Handles.DrawBezier(startPos, endPos, startTan, endTan, shadowCol, null, (i + 1) * 5);
        Handles.DrawBezier(startPos, endPos, startTan, endTan, Color.black, null, 1);
    }

    void CreateNode(Vector2 pos, string title, string name)
    {
        var w = new NodeData();
        w.title = title;
        w.name = name;
        w.window = new Rect(pos.x, pos.y, 300, 100);
        list.Add(w);
    }
}