Tag Archives: detector

Adding checkpoints to a 2D Unity game

This tutorial explains how to add checkpoints to a 2D game so that we can respawn the player back to a checkpoint when the player falls off a platform or off the map. This continues on from the previous tutorial on setting up the fall detector and will be completed when we add the ability to respawn in the next tutorial.

Watch the video below and then scroll down for the sample code.

Sample code

Here is the sample C# code for the CheckpointController script.

using UnityEngine;
using System.Collections;

public class CheckpointController : MonoBehaviour {

  public Sprite redFlag;
  public Sprite greenFlag;
  private SpriteRenderer checkpointSpriteRenderer;
  public bool checkpointReached;

  // Use this for initialization
  void Start () {
    checkpointSpriteRenderer = GetComponent<SpriteRenderer> ();
  }
  
  // Update is called once per frame
  void Update () {
  
  }

  void OnTriggerEnter2D(Collider2D other){
    if (other.tag == "Player") {
      checkpointSpriteRenderer.sprite = greenFlag;
      checkpointReached = true;
    }
  }
}

Next tutorial: Respawn the player

Setting up a fall detector in a Unity 2D game

This tutorial explains how to set up a fall detector in a Unity 2D game that detects when the player has fallen off a platform or off the map and respawns the player back to a checkpoint. This will be covered across three tutorials. We will look at how to add checkpoints in the next tutorial.

Sample code

Here is the sample C# code for the PlayerController script up to the point shown in the above video. This script will be completed in the next two tutorials.

using UnityEngine;
using System.Collections;

public class PlayerController : MonoBehaviour {

  public float speed = 5f;
  public float jumpSpeed = 8f;
  private float movement = 0f;
  private Rigidbody2D rigidBody;
  public Transform groundCheckPoint;
  public float groundCheckRadius;
  public LayerMask groundLayer;
  private bool isTouchingGround;
  private Animator playerAnimation;

  // Use this for initialization
  void Start () {
    rigidBody = GetComponent<Rigidbody2D> ();
    playerAnimation = GetComponent<Animator> ();
  }
  
  // Update is called once per frame
  void Update () {
    isTouchingGround = Physics2D.OverlapCircle (groundCheckPoint.position, groundCheckRadius, groundLayer);
    movement = Input.GetAxis ("Horizontal");
    if (movement > 0f) {
      rigidBody.velocity = new Vector2 (movement * speed, rigidBody.velocity.y);
      transform.localScale = new Vector2(0.1483552f,0.1483552f);
    }
    else if (movement < 0f) {
      rigidBody.velocity = new Vector2 (movement * speed, rigidBody.velocity.y);
      transform.localScale = new Vector2(-0.1483552f,0.1483552f);
    } 
    else {
      rigidBody.velocity = new Vector2 (0,rigidBody.velocity.y);
    }

    if(Input.GetButtonDown ("Jump") && isTouchingGround){
      rigidBody.velocity = new Vector2(rigidBody.velocity.x,jumpSpeed);
    }

    playerAnimation.SetFloat ("Speed", Mathf.Abs (rigidBody.velocity.x));
    playerAnimation.SetBool ("OnGround", isTouchingGround);
  }

  void OnTriggerEnter2D(Collider2D other){
    if (other.tag == "FallDetector") {
      // what will happen when the player enters the fall detector code (this will be added later)
    }
    if (other.tag == "Checkpoint") {
      respawnPoint = other.transform.position;
    }
  }

}

Next tutorial: Adding checkpoints in the game