Advanced Unity Sushi

Add to Your Platformer

Now you have the basics of your platformer game working you can add some new features!

A moving platform would be fun. You already know how to move an GameObject with transform.position, but its not easy to create a function that will move a platform back and forth! Luckily, Unity’s developers created a function that lets you easily move a platform: Mathf.PingPong().

  • To make a moving platform open the “level2” scene from the scenes folder. Also create a C# script and attach it to the top platform in the “level2” scene.

  • Now add this line into the Update() function of your new script:

transform.position = new Vector3((Mathf.PingPong(Time.time, 5f) - 2.5f), transform.position.y, transform.position.z);

How does the code work?

Mathf.PingPong will return a value between 0 and the second parameter (so it will return between 0-5 in this code).

You then need to subtract half the value so the number returned is between -2.5 and 2.5 (that will make it so the platform is centered).

This number is going to be the x position of the platform for the transform.position function!

  • Open the “level3” scene. You should see an evil red cat!

When the evil cat sees either of the players they should lose a life! How do you make the cat see? The answer is by adding Colliders. Colliders are the objects in Unity that trigger a collision. You’ve used collisions to do different things in the past. This time you will make an invisible Collider so it looks like the evil cat can “see”.

  • Open the “evilCat”’s Inspector and click Add Component > Physics 2D > Edge Collider 2D.

Since it is night in this scene, evil cat can’t see that far.

  • So, in evil cat’s Inspector click the box left to Edit Collider. Now move the two ends of the line so they are above the platform evil cat is on. It should look like this:

  • The last step is to add some more code to the “Collisions” script. Change the if statement in OnCollisionEnter2D(collision col) from

if (col.gameObject.tag == "fallzone" && lives > 0)

to

if ((col.gameObject.tag == "fallzone" || col.gameObject.tag == "evilCat") && lives > 0)

Now if the evil cat “sees” one of the players they will lose a life. (The Collider cant be seen in the game view so the player will think evil cat saw them, but you know how evil cat actually “saw” them now!).

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