Monday, April 15th

Class hours: 10:05 – 2:45
Mr. Bohmann | wbohmann@ewsd.org

10:05 Today’s Notes & Attendance

Welcome to Week 31

After this week, you are on vacation – April 20th – 28th

WorkKeys Testing: Richard & Ariel – Wednesday, April 17th – MWing (below Library m-118)

10:10 Mail Check

10:15 Unity

Understanding variables – class vs. local scope variable

Last Friday we created a simple prototype. Later we an add our own look to customize our game.

We created:

A Movement Script for your player so that when you use the A or D key, your paddle moves around
A Ball Script for detecting game over (We coded together with a debug statement)
Add RigidBody 2D to your pinball
Use physics materials (that you create) to manage your bumpers
PlayTest your game
A Respawn your ball if you lose.

All of our Game Objects have data attached to them. The Transform of a gameObject has 9 pieces of primitive data – like location of x, rotation of z and scale, etc….

We can store information about game object values to calculate health, score points, among other game play options. Each value can be stored in a uniquely named storage area called a variable.

A variable is defined with a specific data type (such as int or float) and a name such as myScore or player1Health. You can change the variable’s contents while the program is running – that’s why it’s called a “variable”. We used lots of variables to store data.

public variables are accessible from game play and from other scripts. Private variables, which is the default for variables are available only for that script.

[SerializeField] is a private variable type but is available from game play to adjust while testing

public class MyScript : MonoBehaviour {

   int score;               // declare an int called Score
   float currentDirection;  // declare the float currentDirection
   char myInitial;          // declare a char called myInitial
   string userName;         // declare a string called userName
   bool isMoving;           // declare a bool called isMoving

   void Start () {

      //  numeric data types do not require quotes
      score = 8;

      // use the "F" suffix to specify a float value    
      currentDirection = 90.2F;    

      // use single quotes around individual characters
      myInitial = 'A'; 

      // use double quotes around groups of characters
      userName = "Will Bohmann";  

      // boolean values are either true or false 
      isMoving = true;        
   } 
}

Variable Scope refers to where you place your variables. If you placed your variable in the Start method, it will run when the game begins and then not be accessible again.

We already know that we use variables to provide more code flexibility. In many cases we may want to store mathematical operations in a variable. Let’s look at some common math operations.

int added = 3 + 4;          // added is 7
int subtracted = 3 - 4;     // subtracted is -1
int multiplied = 3 * 4;     // multiplied is 12
int divided = 12 / 4;       // divided is 3
int remainder = 12 % 5;     // remainder is 2

Here is some for our paddle. This script can placed on the player paddle. We declared public Class Level variables and one local scope variable. Do you remember which is which?

The following code will limit our paddle crashing into the wall. We can declare and min and max movement value with a float (because it has decimals!)

    public float paddleSpeed = 3;
    private float hMove;
    private float minXPos; //limit to the left
    public float maxXPos;  // limit to the right

    
    void Start()
    {
        
    }

    void Update()
    {
        hMove = Input.GetAxis("Horizontal") * Time.deltaTime * paddleSpeed;

      //the following code will create the limits left and right for you paddle //using both the global variables and the local scope variable moveX above
       
 if (transform.position.x + hMove > minXPos && transform.position.x + hMove < maxXPos)
 {
     transform.Translate(hMove, 0f, 0f);
 }

10:50 Break

11:00 English with Mx. Yopp

11:50. Pinball – Let’s level up using variables

You can use variables to do important things within your game. For example, many games will need to keep a score. Let’s add a score keeping variable to the pinball game and have the results printed in a Debug.Log statement.

To begin, you will need to declare a variable for score (what type of variable will you use? and where should you put it?). We want the Score to be displayed when the game begins (so we’ll place a Debug.Log statement in the Start() method.

One last decision – which game object should we create the script for?

We’ll also need to make the variable Public so we’ll put it at the top of the script too

void Start () 
{
   // display the current score on start
   Debug.Log ("Score = " + score);
}
//score is a great variable name because it is...semantic!

Inside the OnCollisionEnter2D() function, set the score variable value to 1. Then, again use Debug.Log() to display the current score to the screen.

void OnCollisionEnter2D (Collision2D otherObject) 
{
   // set the score to 1
   score = 1;

    // display the new score
   Debug.Log ("Score = " + score);
}

In the example above, the score just stays at 1. Not entirely what we would want.  So, let's look at using some operational shortcuts in our code to how we can calculate the score each time the ball collides with a gameObject that has a collider.

score = score +1 //adds 1 to the variable
score +=1 //same as above, but add what's on the right to the left
score ++  //means add 1 to the score

Instead of using just the Debug.Log function, we could initialize our score variable at the top of our script as a public variable and then as the game plays we can watch the score increase in the inspector.

Let’s Level Up some more: Setting up Score with the UI Canvas – Instruction
Project Details/Deliverables:

The player’s score should start at 0 when the game begins
The player’s score should be displayed in the top center of the screen
Each time the ball collides with (bumpers paddles, walls, the score should increase by 1
When the game ends, the phrase “Game Over” should be displayed under the score

The big picture – Here is a basic outline of the steps you need to complete the tasks above:

Add a Canvas and two Text objects (one for the score, one for the game over message)
Edit the existing BallScript (or whatever you named your script on the ball) and add a score variable and two public Text variables
Modify the BallScript functions to update the Score and Text variables as needed
Link the two Text objects to the two Text variables in the BallScript