Course Contents — Links to Lessons

A simple way to have popup input and messages is JOptionPane. Please have a look at the document and see how to use them.
In HSA2 we use simpler form gc.showDialog() and gs.showInputDialog()

We are going to be using a graphics library, called HSA2, that removes a lot of the complexity of Swing graphics.
We'll learn Swing graphics in grade 12 programming.
You can find the latest HSA2 package on my GitHub . Download the zip file at home.

Step 1: Learn The Graphics Commands

TODO: Do the Graphics Drawing program
Rubric

Step 2: Basic Animation

a) Read this overview of game loops first.

b) In this step we'll learn how to make a program with something changing on the screen. We'll be using a while loop to do this continually.

Work through the PDF that explains the "Fading.java" program.

This shows

• How to use a while loop to animation drawing
• how to make random locations for drawing circles
• two ways of making random colours

c) Read notes on organizing an animation program

d) Work through the PDF that explains the "Bounce1.java" program.

Step 3: Understanding Movement

a) Read Notes on motion and bouncing
This also shows bouncing off of an immovable object as well as two balls bouncing off each other.

TODO: Take the "Bounce1.java" program that you wrote above, and add the code to actually make the ball bounce.

Step 4: Using Objects for Animation

We use objects to hold all of the variables for a certain thing - e.g. a Ball. All of the variables that control the position, speed, colour, ..., of the shape drawn on the screen can be hidden inside the object.
We can also make multiple balls really easily, like this:
Ball b1 = new Ball(); and Ball b2 = new Ball();

a) Work through the Using objects in graphics program.

TODO: Draw3Circles.java
Note that these balls are not going to bounce yet.

Our objects are almost always
either rectangles e.g. Rectangle paddle = new Rectangle (300,650,100,10); ← this would be for a paddle in Pong or Breakout
or an object the extends Rectangle. e.g. Class Ball extends Rectangle { }

The reason for doing this is that rectangles have a simple intersect() method, though it's not entirely accurate if you have two balls hitting diagonally. They also have another useful method called contains() .

TODO: Work through the TwoBalls.java program. You'll also need Ball.java

When two things collide there are various things we want to do:

• both bounce: balls bouncing off each other
• one disappears: ball hits a brick in brick breaker game. A seagull eats a fish. A player gets a powerup
• both disappear: laser hits enemy. Both the enemy and laser shot disappear.
• only one object bounces: This is tricky. It's covered in a program in Step 3 (above).

How to do various useful things in HSA2

Link Some of this has been covered already

• making a rectangle and drawing it
• determining if a mouse intersects a rectangle
• making a rectangle move (done above in notes on bouncing)
• make a ball object bounce off side of screen (done above in notes on bouncing)
• determining if mouse clicked on a rectangle
• making a second GraphicsConsole to use as an intro screen
• making graphics window start in full screen

TODO: Simple Game. This will use all that you've learned so far. You can also use the techniques from steps 5 and 6 below. Some of you will want to do more complicated things with arrays and arraylists, but we haven't learned those yet (if you can figure them out, great)

Step 5: Keyboard and Mouse Input

• Keyboard input
  Sample program: controlling paddle with keys
• Mouse input
  Sample program: controlling paddle with mouse

Step 6: Timers

How to use Timers
Sample program: Timer showing seconds on screen and pause functionality

Images and Sound

• How to use images
• How to use sound (this needs more work)

ColourRainbow.java is here

Other

Videos about graphics

Go to the Salamander2 youtube channel and watch the videos in order. Make sure that you put cc. on because my voice is often not clear.

The videos discuss pretty much everything we've covered here as well as other things. The basics are: how to make ball objects instead of just a bunch of variables, how to make things collide and bounce, how to make arrays and arraylists of balls, how to add and delete balls.