Driftology/Assets/Waypoint System/Editor/WaypointCircuitEditor.cs

using UnityEditor;
using UnityEngine;

[CustomEditor(typeof(WaypointCircuit))]
public class WaypointCircuitEditor : Editor
{
    private WaypointCircuit _script;

    public override void OnInspectorGUI()
    {
        EditorGUILayout.HelpBox("Create Waypoint By Press Shift + Left Mouse Click On Your Road", MessageType.Info);
        DrawDefaultInspector();
        _script = (WaypointCircuit)target;
    }

    public void OnSceneGUI()
    {
        Event e = Event.current;

        if (e != null && e.isMouse && e.shift && e.type == EventType.MouseDown)
        {
            Ray worldRay = HandleUtility.GUIPointToWorldRay(e.mousePosition);
            if (Physics.Raycast(worldRay, out RaycastHit hitInfo))
            {
                _script.PlaceWaypoint(hitInfo.point);
            }
            else
            {
                Debug.LogWarning("Waypoint Manager: Trying to place a waypoint but couldn't find a valid target. Have you clicked on a collider?");
            }

            if (_script != null)
                Selection.activeGameObject = _script.gameObject;
        }
    }
}