Tuesday, April 29th

Class Hours: 10:05 – 2:40
Mr. Bohmann | wbohmann@ewsd.org

10:05 Today’s Notes & Attendance

EHS students will have class meetings during their advisory time 1:20-1:50 on Friday 5/2

10:10 Let’s make a One Button Game together

and do some Flow Control….

Let’s re-create a classic arcade game (LunarLander) and use our decision-making skills to script the game logic.

The object of the game is to keep the rocket from crashing into the landing platform. This game will be a single button game – we’ll use the up arrow key – that will provide thrust to the rocket. This is a basic game, we all start from somewhere.

Each time the rocket collides with the platform, we’ll program a message response that evaluates the condition of the landing/how hard the rocket touches down, like Crash or Smooth.

We are creating the core mechanics of the game. How would you scale this game? What would make it better or more interesting?

Go to the FunSprites folder and copy down the three sprites in the picture above or you can use your shuttle from the Challenge we did the yesterday but do add the moon and lander.

We’ll build this game in the 2D Playground folder we’ve been working in – name the Game Scene – Lunar Lander

Activity Details:

Create a new scene – Lunar Lander
Organize your gameObjects with layers (background / foreground
Add Colliders to the Lander and Platform
Add Physics to your Lunar Lander
Add a canvas
Create a Script Called LunarLander and add a LunerLander script to your rocket
Add the Adding Unity TMPro library to your script
Add a UI Text called MessageText and place at the top of the screen
Create a public Text variable called messageText (remember you are using new libraries(refresher)
Create an OnCollisionEnter2d function

Each GameObject has one or more components such as a Transform, Rigidbody2D, Collider2D, and so on. You will find that scripting logic will often need to access these components to handle game features. The Transform object is always present, and you know that you can get to Transform properties and functions simply by using the “transform.” variable as shown below.

transform.Translate(0, Time.deltaTime, 0);

However, it’s not as easy to reach other components that are optional. Not all sprites have a Rigidbody2D or Collider2D object attached. To reach these optional components, you need to call the GetComponent() function like this:

Rigidbody2D rb = GetComponent<Rigidbody2D> (); 
//What we are doing is creating a variable called "rb" and it is a RigidBody2D variable

For our LunarLander game, we want to apply an upward thrust to the sprite when an up arrow key is pressed. For realistic movement, we don’t simply want to call transform.Translate() to move the ship upwards. Instead, we want a force to gradually counteract gravity and, if held down long enough, begin moving the ship up the screen. These realistic simulations are handled for us by the Unity physics engine. So, we simply need to get the Rigidbody2D component and call AddForce() to apply a directional force on the sprite. Unity’s Documentation is really helpful. AddForce is a method build into Unity.

rb.AddForce (new Vector2 (0.0F, Time.deltaTime * 650.0F));

The AddForce() function takes a single parameter – a new Vector2 object that contains the forces to be applied in the X and Y directions. We simply want an upwards thrust, so we use 0 for the X and we use a value of 650 multiplied by Time.deltaTime for the Y values. Of course, we are multiplying by Time.deltaTime in order to make the force the same no matter how fast your computer calls the Update() method.

Let’s clean up our code (refactoring)… by creating a function

void Thrust()
 {
     Rigidbody2D rb = GetComponent<Rigidbody2D>();
     rb.AddForce (new Vector2 (0.0F, Time.deltaTime * 650.0F));
 }

Let’s look at the OnCollisionEnter2D() Function

This function will be run when the lander touches the platform. The platform has a BoxCollider2D. The first statement declares a local variable called relativeVelocity. This variable gets a number from the Collision2D object. The Collision2D object contains a property called relativeVelocity that gives us the relative X and Y speeds between the two objects involved in the collision.

void OnCollisionEnter2D(Collision2D platform)
{
   // get the speed at which the lander
   // has hit the platform
   float relativeVelocity = platform.relativeVelocity.magnitude;
   Debug.Log ("relativeVelocity = " + relativeVelocity);

    // ??? add an if/else chain here that will display
   // CRASH if relativeVelocity is greater than 5
   // or SAFE otherwise ???
}

Final Code for your Reference

How about Particles – we can do that – how about adding Custom Fonts – yeah, we can do that too

Custom Fonts with Text Mesh Pro:
Windows/Font Asset Creator/Upload a TruType Font/ Generate Font Atlas
You can get fonts from DaFont

public ParticleSystem smoke;

Quick Challenge – You have all of the necessary tools (examples) to complete the following challenge.

Add a Lander Health Field or a Damage field on your UI canvas
Create some variables at the class level:
- Create a Text type variable (we’ve done two of these already) to capture the damage or lander health
- Create an Int type variable for damage and initialize it to -1
Add a nested If() statement inside of your Crash logic expression
- show damage text on your UI
- Show the lander health or damage score, which adds -1 each time you crash
Add a custom font (go to DaFont) and add your TrueType Font to a Fonts folder in your Project

Bonus – Add a Game Over Message when your damage reaches -3

Super Bonus – reduce your damage by landing correctly.

10:50 Morning Break (10 minutes)

11:00 Unity Certified User Certification Training

12:00 Pinball Game Worksession

Continue working with your pinball game. Review Google Classroom for deliverables.

Health – let’s tackle a prototype version you can use with pinball game. We are going to add the health system to the script we made that handles the collisions. There are dozens of other ways to handle this.

These are our variables we’ll need to add.

public int balls = 3;
public TMP_Text ballCount; //this will be our health
public GameObject killBox; // this will get the game object and then we can set inactive to turn off the respawn script

In the Start we’ll need to show some text

ballCount.text = "Ball Count: " + balls; //this will display the ball count at the start of the game

The Killbox has the respawn script – so we’ll need to access that, as well as use the Trigger that is on the Killbox to let us know what the ball count is

private void OnTriggerEnter2D(Collider2D collision)
{
    balls = balls - 1;
    ballCount.text = "Ball Count: " + balls;
    if (balls <= 0)
    {
        gameoverTxt.text = "You Lose";
        killBox.SetActive(false); //this will turn off the killbox game object
    }
    
}