5.3 Building a 2D Character Controller

A responsive character controller is essential for fun gameplay.

Step 1: Adding Movement

Create a Rigidbody2D component for physics-based movement.

Use a script to capture player input and move the character:

public class PlayerController : MonoBehaviour {
    public float speed = 5f;
    private Rigidbody2D rb;

    void Start() {
        rb = GetComponent<Rigidbody2D>();
    }

    void Update() {
        float moveX = Input.GetAxis("Horizontal");
        rb.velocity = new Vector2(moveX * speed, rb.velocity.y);
    }
}

Step 2: Adding Actions (Jumping)

Add a Collider2D to detect ground contact.

Modify the script to allow jumping when the player is grounded:

public float jumpForce = 10f;
private bool isGrounded;

void OnCollisionEnter2D(Collision2D collision) {
    if (collision.contacts[0].normal.y > 0.5f) {
        isGrounded = true;
    }
}

void OnCollisionExit2D(Collision2D collision) {
    isGrounded = false;
}

void Update() {
    if (Input.GetButtonDown("Jump") && isGrounded) {
        rb.velocity = new Vector2(rb.velocity.x, jumpForce);
    }
}

Step 3: Adding Animation

Use the Animator Controller to create Idle, Walk, and Jump animations.

Write a script to trigger animations based on movement:

animator.SetFloat("Speed", Mathf.Abs(rb.velocity.x));
animator.SetBool("IsGrounded", isGrounded);

Activity: Create a 2D character that can run, jump, and idle, with animations for each state.