Unity have 3 Update functions. Update , FixedUpdate and LateUpdate.
There are differences between these 3. Today we will talk about the differences between these Update functions and why we should care about these. Let’s explore the three main update functions in Unity: Update , LateUpdate , and FixedUpdate. Each of these functions serves a specific purpose in the game loop, and understanding their differences is crucial for effective game development.
1. Update:
Purpose:
The Update method is called once per frame and is commonly used for regular game updates, user input handling, and general game logic. This function is well-suited for actions that are frame-rate independent.
Example:
void Update()
{
// Handle user input
float horizontalInput = Input.GetAxis("Horizontal");
float verticalInput = Input.GetAxis("Vertical");
// Move the player based on input
transform.Translate(new Vector3(horizontalInput, verticalInput, 0) * Time.deltaTime * moveSpeed);
// Other frame-rate independent logic
}
Why Care:
Use Update for most of your game logic and input handling. Since it is frame-rate dependent, the code within it will run differently on different devices based on their frame rates.
2. FixedUpdate:
Purpose:
The FixedUpdate method is called at fixed time intervals and is used for physics-related calculations. It ensures that physics calculations are consistent regardless of the frame rate, making it suitable for rigid body manipulation and other physics interactions.
Example:
void FixedUpdate()
{
// Apply force to a rigid body
rigidbody.AddForce(Vector3.forward * thrustForce);
// Other physics-related calculations
}
Why Care:
Use FixedUpdate for physics-related operations to maintain consistency across various frame rates. It’s crucial when dealing with Rigidbody components and Unity’s physics engine.
3. LateUpdate:
Purpose:
The LateUpdate method is called once per frame, but it’s executed after all Update functions. This makes it suitable for operations that require data from other objects that have already been processed in Update.
Example:
void LateUpdate()
{
// Ensure the camera follows the player after their position is updated in Update
transform.position = playerTransform.position + offset;
// Other operations that depend on positions set in Update
}
Why Care:
Use LateUpdate for actions that require data from other objects processed in Update. This is often used for camera movements that need to follow a target that has already been updated in the current frame.
Conclusion:
Understanding when to use each update function is crucial for developing robust and efficient Unity games. Use Update for general game logic and input handling, FixedUpdate for physics-related calculations, and LateUpdate for actions that depend on the results of Update from other objects.
Remember that these functions provide hooks into the Unity game loop, and utilizing them effectively can help create smooth and predictable gameplay across various devices and frame rates.