Space shooter tutorial scrolling background: which is the better way of implementing it?

Questions & Answers
1

I'm currently working on the "Extending Space Shooter" video tutorial, in the section where it is explained how to create a scrolling background.

Instead of using the technique detailed in the video, I've written my code (see below) such that it changes the offset of the background texture/material on the quad, and I'm wondering which of the two approaches is the more efficient in terms of resource use.

// BGScroller.cs
using UnityEngine;
using System.Collections;

public class BGScroller : MonoBehaviour
{
	public float scrollSpeed;

	private Material bgMaterial;
	private float offsetSpeed;

	void Start ()
	{
		Renderer bgRenderer = GetComponent< Renderer > ();

		bgMaterial = bgRenderer.material;
		offsetSpeed = scrollSpeed / transform.localScale.y;
	}

	void Update ()
	{
		float newOffset = Mathf.Repeat (Time.time * offsetSpeed, 1);

		bgMaterial.SetTextureOffset ("_MainTex", new Vector2 (0, newOffset));
	}
}
2

Why not try it each way and use Unity’s built-in profiler to find out? That way you can even drill in to the details and find out why one way is faster than the other. Learning for yourself tends to be much more rewarding than having someone else analyze it and tell you anyway.

3

From what I can see for myself, it seems that changing the texture offset offers a very slight advantage in terms of CPU time.

My guess is that it’s because the texture offset involves just one arithmetic operation between two floats, while the tutorial’s method also involves some Vector3 math.