scg/ch04/NewtonsApple

001 packagepackage is used to name the directory or folder a class is in scg.ch04;
002 
003 importimport means to make the classes and/or packages available in this program fang2.attributes.Location2D;
004 importimport means to make the classes and/or packages available in this program fang2.core.Game;
005 importimport means to make the classes and/or packages available in this program fang2.sprites.OvalSprite;
006 importimport means to make the classes and/or packages available in this program fang2.sprites.RectangleSprite;
007 importimport means to make the classes and/or packages available in this program fang2.sprites.StringSprite;
008 
009 /**
010  * NewtonsApple - Randomly placed apples fall and mouse-controlled
011  * Newton must be under them when they fall. Score c/d where c is caught
012  * apples, d dropped apples
013  */
014 publicpublic is used to indicate unrestricted access (any other class can have access) classclass is a group of fields and methods used for making objects NewtonsApple
015   extendsextends means to customize or extend the functionality of a class Game {open braces start code blocks and must be matched with a close brace
016   // ----- visual representations of the apple and physicist -----
017   /** on screen representation of the apple; a small red circle */
018   privateprivate is used to restrict access to the current class only OvalSprite apple;
019 
020   /** on screen representation of Newton; a small green square */
021   privateprivate is used to restrict access to the current class only RectangleSprite newton;
022 
023   // ----- keeping and displaying the score -----
024   /** number of apples caught */
025   privateprivate is used to restrict access to the current class only intint is the type for whole numbers and it is short for integer applesCaught;
026 
027   /** number of apples dropped */
028   privateprivate is used to restrict access to the current class only intint is the type for whole numbers and it is short for integer applesDropped;
029 
030   /** on-screen current score; update contents when score changes */
031   privateprivate is used to restrict access to the current class only StringSprite displayScore;
032 
033   /**
034    * Called by FANG forfor is a looping structure for repeatedly executing a block of code each frame. This is where the game checks forfor is a looping structure for repeatedly executing a block of code
035    * and reacts to user input. 
036    */
037   @Override
038   publicpublic is used to indicate unrestricted access (any other class can have access) voidvoid means the method does not return a value advance(doubledouble is the type for numbers that can contain decimal fractions secondsSinceLastCall) {open braces start code blocks and must be matched with a close brace
039     // (1) Move newton so his x-coordinate matches x-coordinate of mouse
040     Location2D position =this assignment operator makes the left side equal to the right side getMouse2D();
041     ifif executes the next statement only if the condition in parenthesis evaluates to true (position !=this is the not equals operator which evaluates to true if both sides are different nullnull is the value used to refer to a non-existant object) {open braces start code blocks and must be matched with a close brace
042       newton.setX(position.getX());
043     }close braces end code blocks and must match an earlier open brace
044 
045     // (2) Translate apple down screen; velocity * time = distance
046     apple.translateY(0.33 * secondsSinceLastCall);
047 
048     // (3) Check if newton has "caught" the apple
049     ifif executes the next statement only if the condition in parenthesis evaluates to true (apple.intersects(newton)) {open braces start code blocks and must be matched with a close brace
050       applesCaught =this assignment operator makes the left side equal to the right side applesCaught +adds two numbers together or concatenates Strings together 1;// another apple caught
051       displayScore.setText("Score: " +adds two numbers together or concatenates Strings together applesCaught +adds two numbers together or concatenates Strings together "/" +adds two numbers together or concatenates Strings together
052         applesDropped);
053       dropApple();
054     }close braces end code blocks and must match an earlier open brace
055 
056     // (4) Check if the apple has hit the ground (y-coordinate >= 1.0)
057     ifif executes the next statement only if the condition in parenthesis evaluates to true (apple.getY() >=this evaluates to true if the left side is not less than the right side 1.0) {open braces start code blocks and must be matched with a close brace
058       displayScore.setText("Score: " +adds two numbers together or concatenates Strings together applesCaught +adds two numbers together or concatenates Strings together "/" +adds two numbers together or concatenates Strings together
059         applesDropped);
060       dropApple();
061     }close braces end code blocks and must match an earlier open brace
062   }close braces end code blocks and must match an earlier open brace
063 
064   /**
065    * place the apple at the initial height and a random horizontal
066    * location
067    */
068   publicpublic is used to indicate unrestricted access (any other class can have access) voidvoid means the method does not return a value dropApple() {open braces start code blocks and must be matched with a close brace
069     apple.setLocation(randomDouble(), 0.00);
070     applesDropped =this assignment operator makes the left side equal to the right side applesDropped +adds two numbers together or concatenates Strings together 1;// another apple dropped
071   }close braces end code blocks and must match an earlier open brace
072 
073   /**
074    * The method called by FANG before the game starts. Include all
075    * "one-time" instructions. Our simple computer games will create and
076    * add Sprites here the game begins. Create and add Sprites; Sprites
077    * are visible things in the game. Once they are added to the game
078    * they are automatically redrawn by the game engine.
079    */
080   @Override
081   publicpublic is used to indicate unrestricted access (any other class can have access) voidvoid means the method does not return a value setup() {open braces start code blocks and must be matched with a close brace
082     // initialize the score
083     applesCaught =this assignment operator makes the left side equal to the right side 0;
084     applesDropped =this assignment operator makes the left side equal to the right side 0;
085 
086     // The apple is small and red; its initial position is set randomly
087     // in the dropApple routine (called here and when apple bottoms out)
088     // our apple is a circle (x and y dimensions are the same)
089     apple =this assignment operator makes the left side equal to the right side newnew is used to create objects by calling the constructor OvalSprite(0.10, 0.10);
090     apple.setColor(getColor("red"));
091     dropApple();
092 
093     // newton is small, green, and begins at the middle bottom of the
094     // screen.
095     newton =this assignment operator makes the left side equal to the right side newnew is used to create objects by calling the constructor RectangleSprite(0.10, 0.10);
096     newton.setColor(getColor("green"));
097     newton.setLocation(0.50, 0.90);
098 
099     displayScore =this assignment operator makes the left side equal to the right side newnew is used to create objects by calling the constructor StringSprite();
100     displayScore.setLineHeight(0.10);
101     displayScore.setColor(getColor("white"));
102     displayScore.topJustify();// move location to upper-left corner
103     displayScore.leftJustify();
104     displayScore.setLocation(0.00, 0.00);
105     displayScore.setText("Score: " +adds two numbers together or concatenates Strings together applesCaught +adds two numbers together or concatenates Strings together "/" +adds two numbers together or concatenates Strings together
106       applesDropped);
107 
108     // for the sprites to be part of the game, they must be added to the
109     // game itself.
110     addSprite(apple);
111     addSprite(newton);
112     addSprite(displayScore);
113   }close braces end code blocks and must match an earlier open brace
114 }close braces end code blocks and must match an earlier open brace
115 
116 //Uploaded on Mon Mar 29 21:39:55 EDT 2010