Scrolling Background

Questions & Answers
1

Now, I’ve watched several videos and tried making their scripts work, but alas I seem to be doing something wrong so I went to the website to see if I could just use the base code and here is what I have.

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class GeneratorScript : MonoBehaviour {

	public GameObject[] availableRooms;
	
	public List<GameObject> currentRooms;
	
	private float screenWidthInPoints;


	// Use this for initialization
	void Start () {
		float height = 2.0f * Camera.main.orthographicSize;
		screenWidthInPoints = height * Camera.main.aspect;
	}
	
	// Update is called once per frame
	void Update () {
	
	}

	void FixedUpdate () {
		
		GenerateRoomIfRequred();
	}


	void AddRoom(float farhtestRoomEndX)
	{
		//1
		int randomRoomIndex = Random.Range(0, availableRooms.Length);
		
		//2
		GameObject room = (GameObject)Instantiate(availableRooms[randomRoomIndex]);
		
		//3
		float roomWidth = room.transform.FindChild("floor").localScale.x;
		
		//4
		float roomCenter = farhtestRoomEndX + roomWidth * 0.5f;
		
		//5
		room.transform.position = new Vector3(roomCenter, 0, 0);
		
		//6
		currentRooms.Add(room);			
	} 

	void GenerateRoomIfRequred()
	{
		//1
		List<GameObject> roomsToRemove = new List<GameObject>();
		
		//2
		bool addRooms = true;        
		
		//3
		float playerX = transform.position.x;
		
		//4
		float removeRoomX = playerX - screenWidthInPoints;        
		
		//5
		float addRoomX = playerX + screenWidthInPoints;
		
		//6
		float farhtestRoomEndX = 0;
		
		foreach(var room in currentRooms)
		{
			//7
			float roomWidth = room.transform.FindChild("Floor").localScale.x;
			float roomStartX = room.transform.position.x - (roomWidth * 0.5f);    
			float roomEndX = roomStartX + roomWidth;                            
			
			//8
			if (roomStartX > addRoomX)
				addRooms = false;
			
			//9
			if (roomEndX < removeRoomX)
				roomsToRemove.Add(room);
			
			//10
			farhtestRoomEndX = Mathf.Max(farhtestRoomEndX, roomEndX);
		}
		
		//11
		foreach(var room in roomsToRemove)
		{
			currentRooms.Remove(room);
			Destroy(room);            
		}
		
		//12
		if (addRooms)
			AddRoom(farhtestRoomEndX);
	}
}

With no luck, I continually get an error!

NullReferenceException: Object reference not set to an instant of an object
GeneratorScript.AddRoom (Single farhtestRoomEndX) (at Assests/Scripts/GeneratorScript.cs:40

This means it can’t find the object I think, but I have it under the room as a child like it says in line 40.

	//3
	float roomWidth = room.transform.FindChild("floor").localScale.x;

48187-screenshot-2015-06-13-184214.png

Any help would be appreciated.

2

Use Debug.log(room.transform.FindChild("floor")), and if it returns null in the console, it was never found, so you’ll have to find the problem there.

Hope it helped.

3

using UnityEngine;

//This script controls the scrolling of the background
public class Background : MonoBehaviour
{
	public float speed = 0.1f;			//Speed of the scrolling
	
	void Update ()
	{
		//Keep looping between 0 and 1
		float x = Mathf.Repeat (Time.time * speed, 1);
		//Create the offset
		Vector3 offset = new Vector3 (0, x);
		//Apply the offset to the material
		GetComponent<Renderer>().sharedMaterial.SetTextureOffset ("_MainTex", offset);
	}
}

I decided to separate some of my code and tried this. I now have it scrolling vertically, but I can’t change it horizontally. What am I missing that I know is right in front of me?