Problem Set 8 Extra Credit

CS111, Wellesley College, Spring 2000

Problem Set 8

Extra Credit

Due: Monday, May 1 at 11:59pm

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Associated with Problem Set 8 are three extra credit problems, which are described below. All are optional, but we encourage you to do at least one. You may do all three if you like.

The extra credit problems are due on the night of Monday, May 1, to give you a little more time to work on them.

The three extra credit problems are described below. Here's a quick overview

Extra Credit Problem 1 asks you to change the Blackjack game to count aces as either 1 or 11.
Extra Credit Problem 2 is an optional problem involving Animation World. This was originally intended to be an assigned problem for Problem Set 8, but we decided to make it optional to give you a chance to work on the open-ended design problem instead (Extra Credit Problem 3) if you would prefer to do that.
Extra Credit Problem 3 is an open-ended design problem for doing something neat in Animation World.

To submit an extra credit problem, follow these steps:

For your hardcopy submission, turn in copies of any files that you have written or modified.
For your softcopy submission, create a folder named extra-credit-N, where N ranges over 1, 2, 3, and put all code necessary to run your program (including the project files, .java files, .class files, and .html files) in this folder. Upload the folder to your ps8 drop folder.

Extra Credit Problem 1 (3 points): Acing Blackjack

Implement a version of the handPoints() method from PS8 Problem 3 which calculates the maximum value of the hand without going over 21 taking into account that aces could be high (11 points) or lo (1 point). If this is not possible, handPoints() should return the minimum value of the hand, which will be greater than 21.

For your convenience, the IntList methods are available in the BlackjackGame if you wish to use them (i.e. you may say empty() instead of IntList.empty()).

Extra Credit Problem 2 (5 points): Screensaver

In this problem we will create a classic screensaver animation. A working demonstration of the screensavers is available from the link above and in the Test folder of ps8_programs. This particular screensaver is a design made of a polygon. We will represent a polygon as an array of Points. A Point is a Java object (part of the graphics library) and its contract is as follows:

Point Contract

// Public instance variables
int x; // x-coordinate of Point
int y; // y-coordinate of Point

// Public Constructor method
public Point (int x, int y);

Since we know what all the instance variables of a Point object are, we draw its representation in ObjectLand as a concrete representation (with straight-edges).

Task 1: MorphingPolygon1

Your task is to flesh out the implementation of MorphingPolygon1. The skeleton for this class is in the file MorphingPolygon1.java. Abstractly, MorphingPolygon1 has the following state variables:

current color of the polygon
collection of Points in the polygon
collection of dx for each Point in the polygon
collection of dy for each Point in the polygon
indication of whether or not the polygon should change colors randomly

dx and dy stand for how much each Point's x and y coordinates should change with each frame (the points in the polygon move independently at different speeds and in different directions). The following are some notes on the methods that you are to flesh out:

You must declare instance variables for this class. You pick the names of the variables. Use arrays for storing the Points, dxs, and dys.
Implement the constructors in the following order:
- public MorphingPolygon1 (int n)
  This constructor should initialize all the state variables and call the resetState method to fill in values for the state variables. A MorphingPolygon created by this constructor should change colors randomly and have n points in the polygon.
- public MorphingPolygon1 ()
  This constructor should call the first constructor with a parameter value of 4.
- public MorphingPolygon1 (int n, Color c)
  This constructor should call the first constructor with the number of points specified. It should also set the color to the color specified. A MorphingPolygon created by this constructor should not change colors randomly. It should always be in the color specified.
- public MorphingPolygon1 (Color c)
  This constructor should call the third constructor with 4 points and the color specified.
resetState
This method should randomly fill in the arrays of Points, dxs, and dys. It should also pick a random color for the polygon if needed. The getRandomColor method from lab is available here. Unlike other Sprites, we are not concerned with saving the initial state of this Sprite. Instead, every time we ask to reset this Sprite, it will generate a new random starting configuration. To fill out this method, you should also fill out the following three private instance methods:
- private int getRandomX ()
  Returns a random number between 0 and the width of the animation, inclusive.
- private int getRandomY ()
  Returns a random number between 0 and the height of the animation, inclusive.
- private int getRandomShift ()
  Returns a random number between 5 and 20 or -5 and -20, inclusive. Should return a positve number about half the time and a negative number about half the time. This method is used to randomly set the value for dx and dy.
Remember that Math.random() will return a random decimal number between 0 and 1 (not including 1).
drawState
To draw the Polygon, a Polygon object must be created. We want to render a closed Polygon with the points in the order they are stored in the array. So, the first Point will be in the Polygon object at its beginning and end. The Polygon should be drawn in the current color.
updateState
Using the same algorithm as that for the bouncing ball (used in lab), update the x and y coordinates of each Point using its corresponding dx and dy. Also be sure to check if the points go out-of-bounds and to compensate accordingly. If the Polygon is supposed to be generated in random colors, give it a new random color every 5 frames.

Task 2: Object Diagram for MorphingPolygon1

Draw an Object Diagram for the result from the following call:
MorphingPolygon1 mp1 = new MorphingPolygon();
Where random numbers or colors are involved, insert your choice of random numbers and colors. We should treat the Sprite class as a black box in our representation of MorphingPolygon1 (i.e. we only want to see the instance variables for this class and not its superclass Sprite). Your drawing should match your implementation of MorphingPolygon1 from Task1.

Task 3: MorphingPolygon2

MorphingPolygon2 extends MorphingPolygon1 to allow for drawing Polygons of different "widths". A width of 1 means that the polygon is drawn once. A width of 2 means that the polygon is drawn twice and the second instance of the polygon is offset a little bit from the first one. The skeleton for this class is in the file MorphingPolygon2.java. The guidelines for fleshing out this class are as follows:

We will need two additional instance variables:
- we need to keep track of the width of the polygon
- we need to know if the different versions of the polygon (in the same frame) should be drawn in the same color or in different colors
We will define two constructor methods:
- public MorphingPolygon2 (int points, int width, Color c)
  This constructor method should call the superclass constructor method with the number of points and the color. The width is the width specified. Since a color is specified, the polygon should be rendered in the same color for all of its instances.
- public MorphingPolygon2 (int points, int width, boolean sameColor)
  This constructor method should call the superclass constructor method with the number of points specified. The width is the width specified. The sameColor boolean indicates whether or not the instances of the Polygon should be rendered in the same color. If true, we will have a polygon that randomly changes color, but in each frame all instances are the same color. If false, we will have a polygon that randomly changes color and all of its instances also randomly change color.
drawState
This is the only method we will override. To draw this polygon, we draw the initial polygon with the current Points. Each additional Polygon is drawn shifted two pixels to the right and two pixels down. Do not worry about rendering the Polygon off the animation screen. If the Polygon is to be rendered in the same color, it will be rendered in the current color. Otherwise, additional instances of the polygon (beyond the first one) should each be rendered in a random color.

To test your Sprites, try out the animations in the ScreenSavers.html file. Each constructor is showcased in a separate animation so you can see if it behaves correctly on its own.

Extra Credit Problem 3 (up to 5 points): Open Ended Animation World Design

This is an open-ended problem to design and implement an interesting animation in AnimationWorld. The possibilities are endless! Do something that you find creative and fun. The number of points awarded will depend on the creativity, artistry, and technical skill involved in producing your animation.