CMSC 110 (Introduction to Computing)

Spring 2011

Assignment#5

Due before start of class on Thursday, November 3, 2011

Task: Design an underwater creature. The creature should be designed so that it can be instantiated as an object. You should be able to create instances of the creature with varying sizes through a single float passed into the constructor. In addition to the constructor, make sure that the class includes methods called display(), move(), getX(), and getY(). 

Step 1:  Cut and paste the following code into a file called Assignment5_<First Initial Last Name>.pde (e.g., my sketch file would be called "Assignment5_EEaton.pde").  Save the sketch immediately.  This is the main file for running assignment 5.  The driver code listed below should be used VERBATIM to run your class, with ONE exception:  in the setup() function, you will need to replace "EEatonObj" with the name of your object, which you will create in step 2.  This is the ONLY change you should make to the code below.

/***************************************
 DO NOT MODIFY FROM HERE ...
****************************************/
 
/** The array of objects */
AnimatedObject[] objs = new AnimatedObject[5];

/** Constant for the sandHeight */
int SAND_HEIGHT = 40;


/** Setup the sketch */
void setup() {
  size(800,600);
  smooth();
  // initialize all the objects
  for (int i=0; i < objs.length; i++) {
    objs[i] = new EEatonObj(random(30,50));   // the one change you'll need to make is changing this line to call your constructor
  }
}


/** The main draw loop */
void draw() {
  
  // draw the tank background
  background(50,50,255);
  
  // draw the sandy bottom of the tank
  fill(168,168,50);
  rect(0,height-SAND_HEIGHT, width, SAND_HEIGHT);
  
  // draw the enhanced tank background, if necessary
  drawTankBackground();
  
  // create the vector of all object's locations
  PVector[] allObjectsLocations = new PVector[objs.length];
  for (int i=0; i<objs.length; i++) {
    allObjectsLocations[i] = new PVector(objs[i].getX(), objs[i].getY());
  }
  
  // draw and animate each of the objects
  for (int i=0; i<objs.length; i++) {
    objs[i].display();
    objs[i].move(allObjectsLocations);
  }
}



/** An abstract class for animated objects */
abstract class AnimatedObject {
  
  /** Constructor
   *  Note that your constructor should accept a single float specifying the size
   */
  
  /** Displays the object */
  abstract void display();
  
  /** Advances the object's animation by one frame 
   *  Note: Implement only one of the move() functions, but NOT both.
   */
  void move() { }
  
  /** Advances the object's animation by one frame.
   *  Note: Implement only one of the move() functions, but NOT both.
   *  @param allObjectsLocations an array of the locations of ALL objects in the environment
   */
  void move(PVector[] allObjectsLocations) { move(); }
  
  /** Getter for the object's x position 
   *  @return the object's x position (as measured from the center of the object)
   */
  abstract int getX();
  
  /** Getter for the object's y position 
   *  @return the object's y position (as measured from the center of the object)
   */
  abstract int getY();
}


/**************************************
 ... TO HERE
***************************************/

Step 2:  Create a file called <First Initial Last Name>Obj.pde (e.g., my file would be called EEatonObj.pde) then cut and paste the following code into the file.  This code must be placed in a different file from the one you created above, and this file should be saved to the same sketch directory as the one you created in step 1.  For ease of running the sketch, keep both files open as tabs in Processing.  It is ESSENTIAL that you name your object and file appropriately, since I will later combine all creatures together into a single aquarium.   

Complete the assignment by implementing your sea creature in this file.

class <First Initial Last Name>Obj extends AnimatedObject { // keep this line as is, except for renaming the class

   /** Constructor */
   <First Initial Last Name>Obj(float size) { ... }

   void display() { ... }

   void move() { ... }

   int getX() { ... }

   int getY() { ... }
}



/** If you want to enhance the tank background
* to showcase your own project, you can put
* drawing code in this function, which is called
* near the start of the draw() function below.
*/
void drawTankBackground() { }

Hints:

• Keep it simple at first.  Start with something basic, get it working, and then build upon it piece by piece, each time ensuring it is working before you move on to the next piece.
• Start with a hand-drawing of what you want, preferrably on graph paper.
• START EARLY!!!  I cannot emphasize this enough.

Extra Credit:

For up to 20 points extra credit, you can make your object react to nearby objects in the aquarium.  Instead of using the move() function defined in step 2, use the following in its place:

/** Advances the object's animation by one frame.
 *  Note: Implement only one of the move() functions, but NOT both.
 *  @param allObjectsLocations an array of the locations of ALL objects in the environment
 */
void move(PVector[] allObjectsLocations) { ... }