Scene.buildIndex

Description

Return the index of the Scene in the Build Settings.

Scene.buildIndex varies from zero to the number of Scenes in the Build Settings minus one. This is because indexes start at zero, so the first Scene is at position zero in the buildIndex. For example, five Scenes in the Build Settings have an index from zero to four.

Unity ignores any numbers in a Scene name. For example, if you add a Scene called scene15 to a list of five Scenes in the Build Settings, Unity gives it a buildIndex of 5.

A Scene that is not added to the Scenes in Build window returns a buildIndex one more than the highest in the list. For example, if you don’t add a Scene to a Scenes in Build window that already has 6 Scenes in it, then Scene.buildIndex returns 6 as its index .

If the Scene is loaded through an AssetBundle, Scene.buildIndex returns -1.

using UnityEngine;
using UnityEngine.SceneManagement;

// Show the buildIndex for the current script.
//
// The Build Settings window shows 5 added Scenes.  These have buildIndex values from
// 0 to 4. Each Scene has a version of this script applied.
//
// In the Project, create 5 Scenes called scene1, scene2, scene3, scene4 and scene5.
// In each Scene add an empty GameObject and attach this script to it.
//
// Each Scene randomly switches to a different Scene when the button is clicked.

public class ExampleScript : MonoBehaviour
{
    Scene scene;

    void Start()
    {
        scene = SceneManager.GetActiveScene();
        Debug.Log("Active Scene name is: " + scene.name + "\nActive Scene index: " + scene.buildIndex);
    }

    void OnGUI()
    {
        GUI.skin.button.fontSize = 20;

        if (GUI.Button(new Rect(10, 80, 180, 60), "Change from scene " + scene.buildIndex))
        {
            int nextSceneIndex = Random.Range(0, 4);
            SceneManager.LoadScene(nextSceneIndex, LoadSceneMode.Single);
        }
    }
}