Best Practices for Using Unity's Update and FixedUpdate Functions

Unity's Update and FixedUpdate functions are an important part of the game development process, as they allow developers to specify when certain actions should be performed in the game loop. It is generally recommended to perform all physics updates in the FixedUpdate function and all non-physics updates in the Update function.

One reason for this is that FixedUpdate is called at a fixed interval, while Update is called as frequently as possible. This can help ensure that physics calculations are consistent and deterministic.

In addition to separating physics and non-physics updates, it can also be a good practice to separate input reading and actions based on input. For example, if you have a complex input system that requires multiple checks or calculations, separating the input reading and action can make your code easier to understand and maintain. However, if your input system is simple and you only need to perform a single action based on the input, it may be more efficient to combine the input reading and action in a single function.

This is an example of how you can use Unity's Update and FixedUpdate functions to separate physics and non-physics updates, as well as input reading and actions based on input:

public class CharacterController : MonoBehaviour {

  private Rigidbody rigidbody;

  private float horizontalInput;

  private float verticalInput;

  void Start() {

    rigidbody = GetComponent<Rigidbody>();

  }

  void Update() {

    // Read input

    horizontalInput = Input.GetAxis("Horizontal");

    verticalInput = Input.GetAxis("Vertical");

  }

  void FixedUpdate() {

    // Perform physics update based on input

    MoveCharacter(horizontalInput, verticalInput);

  }

  void MoveCharacter(float horizontalInput, float verticalInput) {

    // Update character velocity based on input

    Vector3 velocity = new Vector3(horizontalInput, 0, verticalInput);

    rigidbody.velocity = velocity;

  }

}

This code uses the Update function to read input from the player, and the FixedUpdate function to perform a physics update based on that input. The input reading and action are separated into different functions, making the code easier to understand and maintain.

By following these best practices, developers can create smooth, efficient, and well-organized code for their Unity projects.