Computer Science 252
Problem Solving with Java

Fall 2014, The College of Saint Rose

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This week, you will be developing what I hope you will find to be the most interesting program so far: you will develop a "furious fowl" game (legally distinct from Angry Birds, I'm sure).

You may work alone or with a partner on this lab. Only one submission per group is needed.

Getting Set Up

Download the a starter project with partial implementations of some of the programs from here.

Create a document where you will record your answers to the lab questions. If you use plain text, call it "lab5.txt". If it's a Word document, you can call it whatever you'd like, but when you submit, be sure you convert it to a PDF document "lab5.pdf" before you submit it.

Working solutions to all programs can be downloaded here.

Practice Program

Since your main programming task this week involves an ActiveObject a bit different from the ones you've seen, we'll start with a practice program to create an ActiveObject that behaves similarly.

In the BallTossAround folder in the starter you downloaded, you will find a window controller class called BallTossAround that creates a FilledOval every time you press the mouse and passes that FilledOval to the constructor of an active object (which you will implement) that is responsible for moving that ball across the screen as if you "tossed" it upward to the right.

Most (all?) of the active objects we have seen so far are responsible for creating the graphical objects they animate. Here, though, the active object takes the object it animates as a parameter to the constructor.

In addition to the reference to the FilledOval as described in the question above, your run method will also need to know about the canvas (or perhaps just its dimensions) so when the run method animates the ball, it can stop when the ball goes off the bottom or right of the canvas. Its run method should start the ball moving up and to the right, but the ball should be subject to "gravity" - its y speed should increase each time around the animation loop. So you should see the ball trace out a parabolic path. When the ball goes off the bounds of the canvas, the loop should stop and the ball should be removed from the canvas.

Demo

A working solution for the program will appear below. Click inside the applet to interact with it.

Furious Fowl

Your programming assignment is to implement a very simplified version of the popular Angry Birds game, where millions of people spend billions of combined hours launching birds at pigs. (Note that I am not judging or criticizing here, I am a recovering Angry Birds addict.) Since your program will have just one bird and one pig, maybe we could call it "Angry Bird". Better yet, we'll just call it "Furious Fowl". No sense drawing the attention of Rovio's lawyers.

The program stars with a bird sitting on a perch near the bottom left and a pig sitting somewhere near the bottom right of the canvas. To play, you press the mouse and drag around near the bird, resulting in a "sling" that follows your mouse around on one end but which remains anchored to the bird on the other. When you release the mouse, the angle of the sling determines a "launch vector" for the bird. The bird starts moving in the direction you launched him, and flies across the canvas, subject to acceleration due to gravity. The game ends in success if your bird bumps into the pig, or failure if your bird leaves the visible bounds of the canvas before bumping into the pig.

A few more details, hints, and other notes:

• Since your bird is already on the canvas before it starts to be animated, you will use the same idea as in the practice program, where you pass the graphical object to be animated as a parameter to the constructor of the active object.
• The pig should be placed somewhere in the lower right 75 ×75 corner of the canvas.
• There should be a message displayed near the top of the canvas that gives game instructions that change as appropriate depending on whether the mouse has not yet been pressed, the player is dragging to select a launch vector, the bird is in transit, or the game has been won or lost. Note that since the win/lose decision can only be made when the bird hits the pig or leaves the canvas, your active object that controls the bird's flight will need to know about the Text object that contains the message.
• There are a number of image files provided that you can use to create VisibleImage objects of the bird and pig. Note that this is only a small part of this assignment and you can earn nearly full credit if you use a couple of FilledOvals to represent the bird and pig.
• You will probably want a larger canvas than the default 400 ×400 for this program. Note that your program should work for any (reasonable) size canvas. Remember you can either change the default size in your BlueJ preferences or use setSize in your begin method to force it when you run.

Demo

A working solution for the program will appear below. Click inside the applet to interact with it.

Bonus Opportunity

You can earn up to 5 points of bonus for enhancements to the programming assignment. Check with your instructor for point values for any enhancements you wish to attempt.

Submitting

Before 11:59 PM, Friday, October 17, 2014, submit your lab for grading. There are three things you need to do to complete the submission: (i) Copy your file with the answers to the lab questions into your project directory. Be sure to use the correct file name. If you prepared your answers in Word, export to a PDF file and submit that. (ii) Upload a copy of your lab (a .7z or .zip file containing your project directory) using Submission Box under assignment "Lab5". (iii) Demonstrate the execution of your programs for your instructor. (2 business day grace period for demos).

Grading

This assignment is worth 70 points, which are distributed as follows: