DT228/DT282 Object Oriented Programming 2020-2021

Teams Links for online classes:

Resources

Install the software you will need for this module

Contact the lecturer

Email: bryan.duggan@tudublin.ie
Twitter: @skooter500

Assessments

Assignments
Week 11 Lab Test 20%
Week 13 Assignment Submission - 30% - Submit Here
End of Year exam - 50%

Previous Years Lab Tests

Week 12

Tutorial

Video of the tutorial

Solution to this coding bat exercise:

public int countYZ(String str) {
  int count = 0;
  for(int i = 0 ; i < str.length(); i ++)
  {
    char c = Character.toLowerCase(str.charAt(i));
    if (c == 'z' || c == 'y')
    {
      if (i == str.length() - 1 || ! Character.isLetter(str.charAt(i + 1)))
      {
        count ++;
      }
    }
  }
  return count;
}

Solution to this coding bat exercise:

public String withoutString(String base, String remove) {
  String lcBase = base.toLowerCase();
  String lcRemove = remove.toLowerCase();

 

  String ret = "";
  int start = 0;
  int i = lcBase.indexOf(lcRemove);
  while (i != -1)
  {
    ret += base.substring(start, i);
    start = i + remove.length();
    i = lcBase.indexOf(lcRemove, start);
  }
  ret += base.substring(start);
  return ret;
}

Lab

Lab Test
Solution is in the solution branch

Lecture

Week 11 - Polymorphism, interfaces & strings

Tutorial

Video of the tutorial
Solution to the lab test is in the "solution" branch of this repo

Lab

Link to the test

Lecture

Video of the class

Solution to this coding bat problem:

public int countCode(String str) {
  int loc = str.indexOf("co");
  int count = 0;
  while(loc != -1)
  {
    if (str.length() > loc + 3 && str.charAt(loc + 3) == 'e')
    {
      count ++;
    }
    loc = str.indexOf("co", loc + 2);
  }
  return count;
}

Lab

Lab Test

Week 10 - Inheritance & Abstract Classes, Bullets in the YASC game

Lecture

Tutorial

Video of the tutorial

Week 9 - YASC

Tutorial

Video of the tutorial

Lecture

Lab

Part 1

Fork this repo which has the starter code and examples for your assignment. Clone your fork and make sure it compiles and runs ok.

Part 2

Today you can make two more classes to encapsulate the behaviour of health and ammo powerups as per this video:

To complete this lab!

Update your forks of the master branch to get the code for the moveable Player we made in Monday's class. Create a branch for your work today.
Make a class called Health. Initially it should spawn off screen and move in a random direction onscreen. It could spawn from the top, bottom, left or right side of the screen. You can use yasc.random to generate random numbers. I wrote a respawn method on the class and call it from the constructor to set the initial x, y, dx and dy values. Notice how the health is drawn and notice in the video that the health is rotating as well as moving. If the health goes off the side of the screen it should respawn. Don't forget to create an instance of the Health in YASC.java and call update and render.
Do the same for Ammo
Add health and ammo fields to the Player class and print the health and ammo beside the player
Add code in YASC.java to check collisions between the player and either of the powerups and add to the player's health and ammo stats. To check collisions, you can check id the distance between the player and the powerup < the sum of the two radii. You can use the dist function to calculate the distance.

Week 8 - Frequency Domain Analysis, transcription, frequency bands

Lecture

Video of the class
- FFT visualisation, transcription, audio bands

Tutorial

Video of the tutorial
- We did some coding bat exercises and also made a 3D cube that responds to sound:

No lab due to the bank holiday

Week 7 - Audio

Tutorial

Video of the Tutorial

Lab

Learning Outcomes

Practice for loops
Demonstrate an understanding of how digital audio works
Practice computational thinking and problem solving
Have fun making beautiful things

Update your forks and have a look at Audio1.java this is the code we wrote on Monday with some modifications. Checkout the keyPressed function. This starts and restarts the audio file when you press space. Also it sets the value of the which variable to be the numbers 0-5 when you press the appropriate key on the keyboard. If your computer wont play the audio file for some reason,you can uncomment the code to read audio from the microphone instead or use a .wav file instead.

Ok now check out this video of 5 visuals you can make today. Pressing the keys 0-4 on the keyboard should change the visual in your sketch.

0 - The wavy lines visual
1 - The waveform
2 - The waveform drawn down the 4 sides of the screen
3 - The circle - Use the lerped amplitude to control the size of the circle
4 - The square - Again use the lerped amplitude to control the size of the square. You can also use rectMode(CENTER) to make the x and y parameters of the rect function determine the center of the rect rather than the coordinates of the top left corner
5 - There is no visual associated with 5 in the video, so come up with your own!

Lecture

Some audio responsive stuff I have been working on recently:

Week 6 - Star Map ArrayList, classes, CSV files

Lab

Learning Outcomes

Make a class
Make constructors & accessor methods
Use an ArrayList
Develop problem solving & algorithm design skills

Try this lab test from last year. You can use the StarMap example we made in the class on Monday for help.

Tutorial

Video of the tutorial (Solution to the lab)

Lecture

Video of the class

Week 5 - Conway's Game of Life

Tutorial

Lab

Video of the lab

Learning Outcomes

Learn how to iterate over a 2D array
Explore the magic of cellular automata
Learn how to use map

Update your fork of the repo from the master branch to get the bug fixed code from Monday's class and create a branch for your work today. I discovered another bug in the code we wrote on Monday. In countNeighbours, the line:

if (r != row && c != col)

Should have been:

if (! (r == row && c == col))

In Life.java:

Write the method updateBoard. This method should iterate over the board cell by cell using a nested for loop and apply the Game of Life rules:

If the cell is alive (true) then if the cell has exactly 2 or 3 neighbours it survives (gets set to true), otherwise it dies (gets set to false)
If the cell is dead (false) then it comes to life if it has exactly 3 neighbours, otherwise it stays dead in the next generation.

This is important so please read carefully!!

You have to read values from board, but you set values in next, which is a 2D array the same size as board. At the end of the method you swap board and next. I have left the swapping code in the method, so you don't have to write it. This is so that when you for example, kill a cell or bring a cell to life, you don't screw up the count for other cells in that generation.

Again - in updateBoard

Write a nested for loop that gets the row and col for every cell
Count the neighbours (use the method we wrote on Monday for this)
Check if the cell is alive, apply the rules for alive cells to next
If the cell is dead, apply the rules for dead cells to next
Swap board and next

Your game of life should look like this if you implement the rules correctly (click the image for a video):

Some extra things you can implement you can see in the video:

Increase size and change the size of the screen and see what effect this has on the simulation
Press space to pause and resume the simulation
Press 1 to randomise the board again
Press 2 to clear the board
Press 3 to draw a cross shape and see how it evolves
Drag the mouse across the window to set cells at the mouse position to be alive.

Some extra things you can implement that are not in the video

Draw a glider at the mouse position. This is starting pattern that will evolve a pattern that walks across the screen
Draw a Gosper Gun at the mouse position. This is a starting pattern that will spawn creatures indefinitely

You can read more about these starting patterns and others in this wikipedia article and see examples in this video:

If you want to learn more about cellular automata check out:

Lecture

There is a bug in the code we wrote in the class:

The bounds checking on the arrays we wrote in the class is:

if (row > 0 && row < size -1 && col > 0 && col < size -1)

And it should be

if (row >= 0 && row < size -1 && col >= 0 && col < size -1)

Thanks to Luke O Shea Scanlan for pointing this out!

I pushed the corrected code to the repository

Week 4 - Arrays

Lab

Learning Outcomes

Practice iterating over arrays
Practice computational thinking

Check out this video of the assignment I wrote in GWBasic for the statistics module in first year WMT in Kevin St in 1990 (click the image for video):

And here is the source code in case you are interested!

Inspired by the video, see if you can write code to generate the following graphs of the rainfall data. Start with the file Arrays.java. You will find these much easier if you use the map function we learned in Monday's class.

When you are doing these, make sure your code works even if you change the size of the drawing window or change the values in the array.

A bar chart:

Start by drawing the axis, then draw the ticks and print the text, then draw the bars. You can use textAlign(CENTER, CENTER) to align the text Use the HSB color space to assign different colors to each bar
A trend line:

This one is a bit trickier because you have to calculate the start xy and end xy for each line. Your for loop for drawing the trend lines can start at 1 instead of 0 and then you can get the previous value for the start of each line by taking rainfall[i - 1].
A pie chart

You can use the the arc function to draw arcs and sin & cos to calculate the x and y coordinates to print the text. This one is the most challenging. Remember that a pie chart shows the proportion of each data point in the sum of all the data, so you will have to calculate the sum of all the rain fall and figure out how much each month is relative to the sum. It's best to draw the segments first and then draw the labels. Your map function might look something like this:
```
 float angle = map(rainfall[i], 0, sum, 0, TWO_PI);
```

Don't forget to update your forks of the repository from my master branch and create a new branch for your work today!!

Lecture

Week 3 - Git, the if statement and loops in Java

Tutorial

Video of the tutorial going through the lab solution

Lecture

Read the git manual
The if statement
While loops
For loops
Video of the class
Markdown tutorial

Lab

Learning outcomes

Practice procedural drawing with loops
Develop computational thinking skills, by making variables and constructing algorithms

Update your forks of the repo to get the code we wrote on Monday and create a branch for your work today. Don't commit onto the master branch!

Complete the procedural drawing exercises below by editing the file Loops.java. You can check the value of the "which" variable which will be in the range 0-9 and use this to determine which exercise gets drawn. There are > 12 exercises so some of the numbers will have to draw more than one exercise.

Procedural drawing exercises:

if statement

3 exercises. Click the image for video:

for loops:

Use a loop, rect and the HSB colour space:

Use a loop, ellipse, and the HSB colour space:

Use a loop, ellipse and the HSB color space to draw this:

Use a nested loop to draw this:

Try and draw this using ONE for loop. You will need the text and textAlign functions:

Use a nested loop to draw this:

Use sin and cos to draw this:

Use line, sin and cos to draw regular polygons like squares, pentagons, octogons etc:

Draw a procedural star like these:

Week 2 - Hello Processing

Tutorial

Solution to the lab video

Lab

Learning Outcomes

Practice drawing stuff and working out co-ordinates
Practice using variables and if statements in Java

This is a video of a silly game called Bugzap made in Java using the Processing libraries. Today we can make a part of this game in order to get some practice using variables in Java.

How you should do it:

Ok let's get the main game working first and not worry about the splash screen and the game over screen

Update your fork of the repository from the master branch. To do this, cd to the folder where you have cloned your repository, (or clone it somewhere if you need to) and type:

git checkout master
git pull upstream master

Create a branch for your work today by typing:

git checkout -b lab2

Create a new class called BugZap.java in the ie.tudublin folder. Make it extend PApplet and add the settings, setup and draw methods. Check out HelloProcessing2.java if you need examples for these. This class also has examples of the drawing methods with comments. You can also check out the Processing reference if you are unsure about any of the methods.
Call size in settings to set the size of the drawing window.
Edit the file Main.java so that it starts the BugZap class instead of the HelloProcessing2 class. I'll let you figure out how to do this :-)
Make sure everything works by compiling and running your program before continuing!

Now we can draw the bug.

Make fields of type float in the BugZap class for playerX, playerY and playerWidth and give these default values. You can decide what these should be. There are built in variables called width and height that give the width and height of the drawing window. These only get assigned after size has been called, so if you want to use these to give values to playerX, playerY etc. put the code into the setup method.
Write a method called void void drawPlayer(float x, float y, float w) that draws the player character, centered around the parameters x, y. You can use the line method to do this. You can pass variables as parameters to this method and also things like x + 20, w * 0.5f etc. I made an extra variable in this method called h for the height and set it to be half the w parameter. Don't forget to set the stroke color!
Call this method from draw, passing in the parameters playerX, playerY and playerWidth.
Compile and run everything to make sure it's working before continuing.
If everything is working ok, you should see the bug on the screen

Now lets get the player moving in response to the keys

Add this method to BugZap.java:

public void keyPressed()
	{
		if (keyCode == LEFT)
		{
			System.out.println("Left arrow pressed");
		}
		if (keyCode == RIGHT)
		{
			System.out.println("Right arrow pressed");
		}
		if (key == ' ')
		{
			System.out.println("SPACE key pressed");
		}
	}

If you compile and run the program again you will see that some messages get printed out when you press various keys. If you are running in Visual Studio Code, you will see these messages appear in the Debug Console
Modify this method to increment and decrement the playerX variable instead and you should be able to get the player to move left and right
You might want to add if statements to this method to stop the player moving off the left and right side of the screens. If statements in Java are almost the same as in C!
When the player presses SPACE you will want to draw a line for the player's laser.

The Bug

In a similar way to how you made the player, make the Bug. Make variables and drawBug method. Don't forget to call the method from draw()
To move the bug you can add a random amount to it's x coordinate on intervals. To generate a random number you can use the random function.
One way to make stuff happen on an interval rather than every frame is to use the frameCount variable. This variable is a field in PApplet and it gets incremented automatically every time draw is called. Because draw gets called 60 times a second, you can do something every second with this code:

if ((frameCount % 60) == 0)
{
    // Do something
}

You can print text to the screen using the text function.

Ok you should now have the basics working. See if you can figure out how to check to see if the player hits the bug, add scoring, splash screen, game over screen and sound.

Lecture

Check out the HelloProcessing2 class in the repo
We drew the all seeing eye using the Processing drawing methods
if statement exercises

Week 1 - Introduction

Tutorial

Coding Bat

Lab

Learning outcomes

Set up Java, Visual studio code and the Java Extensions
Fork the repo, configure the upstream remotes
Write your first Java code using command line tools
Test out Visual Studio Code

Part 1 - Installing Java

Install the software you will need for this module and set up your path to the Java Development Kit. This document explains how to do it.

Part 2 - Forking the repo

Firstly fork this repository by clicking the fork button above, so that you get your own copy of the course repo to work on this semester. Now create a new empty folder on your computer somewhere right click on the folder and choose git bash here. Alternatively you can start the bash and cd to the new folder. To clone the repository for your fork:

git clone https://github.com/YOURGITUSERNAME/OOP-2020-2021

Replace YOURGITUSERNAME with your github username. You can also copy the URL to the repo from your browser and paste it into the console. To paste into the bash on Windows is right click. You can use Cmd + C, Cmd + V on the Mac.

Now cd into the repo and check the origin and upstream remotes are set up correctly

cd OOP-2020-2021
git remote -v

You should see something like this:

origin  https://github.com/YOURGITUSERNAME/OOP-2020-2021 (fetch)
origin  https://github.com/YOURGITUSERNAME/OOP-2020-2021 (push)
upstream  https://github.com/skooter500/OOP-2020-2021 (fetch)
upstream  https://github.com/skooter500/OOP-2020-2021 (push)

If you don't see the upstream remote, you can set it up by typing

git remote add upstream https://github.com/skooter500/OOP-2020-2021

You can read more about forking a git repository and setting up the upstream remote in this article

Once the upstream is setup, you will be able to push code to your own repo and also keep it up to date with the master branch of the changes I make each class.

If you already forked the repo before the lab, you may need to update your master branch from my master branch to get the changes I made:

git fetch
git checkout master
git pull upstream master
git push

Part 3 - Compiling & running Java

To compile and run the Java code in the src folder, you should type:

cd java
javac src/ie/tudublin/*.java -d bin
java -cp bin ie.tudublin.Main

You should see

Hello world
Misty
TopCat
Garfield
Garfield

On the terminal. If you do, then congratulations! You have successfully compiled and run your first Java program using the command line tools. Now create a branch to store your changes today. Best not to modify the master branch so you can keep it up to date with my changes:

git checkout -b lab1

Use an editor (like Visual Studio code or notepad++) to open up the files in the folder src/ie/tudublin and study them to see if you can figure out what's happening. Modify the code as follows:

Make a private int field on the Cat class called numLives.
Write public accessors for the field (see how I did this for the name field on the Animal class)
Set the value of this field to 9 in the Cat constructor
Write a method (functions are called methods in Java) on the Cat class called kill. It should subtract 1 from numLives if numLives is > 0 and print the message "Ouch!". If numLives is 0, you should just print the message "Dead"
Create a new instance of the Cat class like this
```
Cat ginger = new Cat("Ginger");
```
In the Main class in a loop, call kill on ginger until ginger is dead.
Compile and run your program until you have no bugs and you get the desired output.

Commit and push your changes:

git add .
git commit -m "killing the cat"
git push --set-upstream origin lab1

The "--set-upstream origin lab1" option is only required the first time you commit onto a new branch. After that you can just type "git push"

Part 4 - Hello Processing

Checkout the branch HelloProcessing by typing

git checkout HelloProcessing from the bash

In Visual Studio Code, choose File | Open Folder and open the OOP-2020-2021 folder. Press F5 and if all goes well, you should see something that looks like this:

If you are done check out the references for classes, packages, constructors and accessors below.

Also! Read the first three chapters of the git manual.

Lecture

Some assignments from previous years: