Computer Science 120
Introduction to Programming

Spring 2011, Siena College

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For the second programming project, you are to develop a Java program to play a game where you click on bouncing balls. There are some basic requirements, but many of the game's details are up to you.

You must work alone on the program. You may ask your instructor questions, but help will be limited. You may not discuss the program with anyone else including your classmates and the computer science tutors until after everyone has submitted their programs. You may consult your own graded or ungraded lab submissions, your own class notes, and any class examples or notes available from the course web page. Think of this as an open-book lab exam. Any collaboration or consultation of unauthorized sources will be considered a breach of academic integrity and will be dealt with according to the course policies outlined on the syllabus.

While no design will be graded for this program, coming up with a written design is likely to be a beneficial first step.

Note that a significant portion of the credit for the project is for style, design, documentation, and efficiency. While everyone should strive to earn all of the correctness points, you may find that a well-designed, thoroughly-commented program that makes appropriate use of variables and constants but does not quite implement all functionality will earn a higher grade than a perfectly-functioning program that uses poor variable names, does not use named constants, is uncommented, or is poorly formatted.

Have fun and good luck!

Click-a-Ball Game

For this program, you are to develop a class BallGame (an extension of WindowController) that draws a playing field and creates Ball objects that move around the canvas until they are clicked. The requirements are as follows.

• Each time the mouse is pressed on an empty area of the playing field, a randomly sized and colored ball is drawn at the top of the playing area at an x-coordinate which is either dependent on the press point or generated randomly.
• Implementation of the game must include an ArrayList containing the balls on the screen.
• The balls should move around the playing field with random velocity. They can bounce off walls and will stay in play until selected. If a ball is selected (clicked on), it should disappear.
• Basic functionality: you may earn 75% of the functionality points for a game that performs the minimal specifications.
• Enhanced functionality: the remaining 25% of the functionality points will be awarded for features of your choice. You may add a scoring scheme and ways to "win" or "lose", other rules for the creation, movement, and selection of the balls, that will make the game more fun to play. Be creative! To ensure that your submission is eligible for full credit, please have each enhancement you intend to implement approved and given a point value by your instructor.
• You must submit a typed description of the rules of your game along with your source code printout. Please indicate any added functionality and the points agreed upon with your instructor for each feature.

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

Submitting Your Work

Before the start of your next lab session, submit your Java programs for grading. There are three things you need to do to complete the submission: (i) place a copy of your Javas program into your csis120/hw folder under hw9, (ii) print a copy of each of your programs and hand it to your lab instructor, and (iii) demonstrate the execution of your programs for your instructor.

Grading Sheet

This project is worth 100 points, which are distributed as follows: