Enables the Editor to handle an event in the Scene view.
In the OnSceneGUI you can, for example, edit meshes, paint terrain, or have advanced gizmos. Refer to the Handles class for methods related to drawing interactable visuals in the SceneView.
In the following two scripts, OnSceneGUI is used to draw lines between GameObjects. The first script shows how OnSceneGUI is used. In this script, a GameObject is used as a parent. The script obtains the position of the parent and then draws lines from that position to GameObjects stored in an array. The script uses Handles.DrawLine to draw lines. The documentation for Handles.DrawLine has a very similar example.
using UnityEngine; using UnityEditor;
[CustomEditor( typeof( DrawLine ) )] public class DrawLineEditor : Editor { // draw lines between a chosen game object // and a selection of added game objects
void OnSceneGUI() { // get the chosen game object DrawLine t = target as DrawLine;
if( t == null || t.GameObjects == null ) return;
// grab the center of the parent Vector3 center = t.transform.position;
// iterate over game objects added to the array... for( int i = 0; i < t.GameObjects.Length; i++ ) { // ... and draw a line between them if( t.GameObjects[i] != null ) Handles.DrawLine( center, t.GameObjects[i].transform.position ); } } }
This script stores the array of GameObjects which have a line drawn to them. This regular script is attached to a GameObject which is considered to be the starting point for all lines.
using UnityEngine;
[ExecuteInEditMode] public class DrawLine : MonoBehaviour { // an array of game objects which will have a // line drawn to in the Scene editor public GameObject[] GameObjects; }