The Bird Script

Checked with version: 5.5


Difficulty: Beginner

In this beginner friendly live training we will look at creating a simple 2D Flappy Bird style game. We'll cover best practices for infinite or endless games, basic object pooling and creating cartoon physics effects.

The Bird Script

Beginner 2D Game Creation


Code snippet

using UnityEngine;
using System.Collections;

public class Bird : MonoBehaviour 
    public float upForce;                   //Upward force of the "flap".
    private bool isDead = false;            //Has the player collided with a wall?

    private Animator anim;                  //Reference to the Animator component.
    private Rigidbody2D rb2d;               //Holds a reference to the Rigidbody2D component of the bird.

    void Start()
        //Get reference to the Animator component attached to this GameObject.
        anim = GetComponent<Animator> ();
        //Get and store a reference to the Rigidbody2D attached to this GameObject.
        rb2d = GetComponent<Rigidbody2D>();

    void Update()
        //Don't allow control if the bird has died.
        if (isDead == false) 
            //Look for input to trigger a "flap".
            if (Input.GetMouseButtonDown(0)) 
                //...tell the animator about it and then...
                // out the birds current y velocity before...
                rb2d.velocity =;
                //  new Vector2(rb2d.velocity.x, 0);
                // the bird some upward force.
                rb2d.AddForce(new Vector2(0, upForce));

    void OnCollisionEnter2D(Collision2D other)
        // Zero out the bird's velocity
        rb2d.velocity =;
        // If the bird collides with something set it to dead...
        isDead = true;
        //...tell the Animator about it...
        anim.SetTrigger ("Die");
        //...and tell the game control about it.
        GameControl.instance.BirdDied ();