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How to Utilize Update in Unity

0 Comments ยท May 7, 2023

The Update function in Unity is a built-in function that is called once per frame and is commonly used to update the state of game objects and perform other game logic. Here are some tips on how to properly utilize the Update function in your code.

1. Time.deltaTime

Since the Update function is called once per frame, it's important to use Time.deltaTime to ensure that your updates are frame-rate independent. This means that your updates will execute at the same rate regardless of the frame rate, ensuring that your game behaves consistently across different hardware.

For example, if you wanted to move an object at a constant speed, you would multiply the movement vector by Time.deltaTime to ensure that the object moves at the same speed regardless of the frame rate:

void Update() {
    transform.position += Vector3.forward * speed * Time.deltaTime;

2. Avoid Expensive Calculations

As mentioned previously, since the Update is called once per frame, it's important to avoid performing expensive calculations that could impact performance. For example, if you have a complex algorithm that takes a long time to execute, you might consider moving it to a separate thread or breaking it up into smaller chunks that can be executed over multiple frames.

3. Use FixedUpdate for Physics

If you're working with physics in your game, it's recommended to use the FixedUpdate function instead of Update. FixedUpdate is called at a fixed rate, which is determined by the physics time step, and is designed to handle physics calculations like collision detection and rigid body movement. Using FixedUpdate for physics calculations can help ensure that your game physics behaves consistently and accurately across different frame rates.

4. Consider Using Coroutines

If you need to perform an update that isn't tied to the frame rate, you might consider using a Coroutine instead of an Update. Coroutines allow you to pause the execution of a function for a specified amount of time, allowing you to perform time-based updates like spawning enemies or delaying an animation.

IEnumerator SpawnEnemy() {
    while (true) {
        Instantiate(enemyPrefab, spawnPoint.position, Quaternion.identity);
        yield return new WaitForSeconds(spawnDelay);

To start a Coroutine simply call StartCoroutine once, like this:


To stop a Coroutine, you can use the StopCoroutine method which takes a reference to a Coroutine, IEnumerator, or a method name (Storing a reference from a StartCoroutine and using that to stop is a preferable approach since it knows exactly which instance of a Coroutine to stop):

Coroutine a = StartCoroutine(SpawnEnemy());



By following these best practices, you can properly utilize the Update function in your Unity scripts and write efficient, high-performance code.

Learn the differences between Update functions in Unity

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