Tutorial:Wackadot

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package YourName.wackadot;

import wiki.Wiki;
import fang.*;
import java.awt.*;
import java.awt.geom.*;

/**
* All about my game here.
* @author YourName
*/
public class Wackadot extends GameLoop
{
   private Sprite dot;
    
   public void startGame()
   {
       makeSprites();
       addSprites();
   }
    
   private void makeSprites()
   {
       dot=new OvalSprite(1, 1);
       dot.setScale(0.1);
       dot.setLocation(0.5, 0.5);
       dot.setColor(Color.RED);
   }
    
   private void addSprites()
   {
       canvas.addSprite(dot);
   }
}

Line 1: declares the package this class resides in

Line 14: declares a Sprite instance variable that will be used in the game logic eventually.

Lines 16-20: the startGame method is called when the Start button is pressed the first time. In this method, you need to make and add all the sprites. Note: for multiplayer games, the number of players is only available once the startGame method is called.

Lines 22-28: helper method for constructing and placing sprites. The positions and sizes are relative to a screen which spans (0, 0) to (1, 1).

Lines 30-33: helper method for adding sprites to the canvas. Simply making a sprite does not make it visible. Sprites are only visible once they are added to the canvas within the bounds of the canvas and sized properly.

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   public void advanceFrame(double timePassed)
   {
      Point2D.Double mouse=
          getPlayer().getMouse().getLocation();
      dot.setLocation(mouse);
   }

Line 34: this line is intentionally left blank. In general, it is good practice to leave a blank line between methods

Line 35: this method is called automatically between each frame calculated/displayed.

Lines 37-38: gets the mouse of the current player.

Line 39: places the sprite at the same position as the mouse.

Line 40: close brace ending the advanceFrame method. Every method body begins and ends with braces.

Last Line of your Code: don't forget the close brace for your entire program. The very last character in every single program is a close brace. Leaving off the close brace will cause many errors to appear. Every class body begins and ends with braces.

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private Sprite redDot;
private Sprite blueDot;

Line 15: declares the red dot

Line 16: declares the blue dot

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private void makeSprites()
{
   dot=new OvalSprite(1, 1);
   dot.setScale(0.1);
   dot.setLocation(0.5, 0.5);
   dot.setColor(Color.RED);

   redDot=new OvalSprite(1, 1);
   redDot.setScale(0.1);
   redDot.setLocation(
          random.nextDouble(),
          random.nextDouble());
   redDot.setColor(Color.RED);

   blueDot=new OvalSprite(1, 1);
   blueDot.setScale(0.1);
   blueDot.setLocation(
          random.nextDouble(),
          random.nextDouble());
   blueDot.setColor(Color.BLUE);
}

private void addSprites()
{
   canvas.addSprite(dot);
   canvas.addSprite(redDot);
   canvas.addSprite(blueDot);
}

Lines 34-35, 41-42: uses the provided random number generator to get a random number between 0 and 1.

Lines 49-50: adds the sprites to the canvas to make them visible

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private void repositionRandomly(Sprite sprite)
{    
   sprite.setLocation(
       random.nextDouble(), 
       random.nextDouble());
}

private void handleCollisions()
{    
   if(dot.intersects(blueDot))
   {
       repositionRandomly(blueDot);    
   }    
   if(dot.intersects(redDot))    
   {
       repositionRandomly(redDot);    
   }
}

public void advanceFrame(double timePassed)
{
   Point2D.Double mouse=
       getPlayer().getMouse().getLocation();
   dot.setLocation(mouse);
   handleCollisions();
}

Lines 53-58: helper method for randomly positioning the dot.

Lines 60-70: helper method for handling dot collisions

Lines 62-65: if the dot moving with the mouse collides with the blue dot, then the blue dot is positioned in a random location.

Lines 66-69: if the dot moving with the mouse collides with the red dot, then the red dot is positioned in a random location.

Lines 72-78: don't duplicate the advanceFrame method, just add line 77.

Line 77: calls the helper method for handling collisions

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private void handleCollisions()
{
   if(dot.intersects(blueDot))
   {
       repositionRandomly(blueDot);
       if(dot.getColor().equals(Color.BLUE))
       {
           dot.setColor(Color.RED);
       }
   }
   if(dot.intersects(redDot))
   {
       repositionRandomly(redDot);
       if(dot.getColor().equals(Color.RED))
       {
           dot.setColor(Color.BLUE);
       }
   }
}

Lines 65-68, 73-76: checks to see if the dot intersected matches the color of the dot. If it does, the color of the dot is changed to the other color.

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private StringSprite scoreSprite;

Line 17: a sprite which will consist of text

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private void makeSprites()
{
   dot=new OvalSprite(1, 1);
   dot.setScale(0.1);
   dot.setLocation(0.5, 0.5);
   dot.setColor(Color.RED);

   redDot=new OvalSprite(1, 1);
   redDot.setScale(0.1);
   redDot.setLocation(
          random.nextDouble(),
          random.nextDouble());
   redDot.setColor(Color.RED);

   blueDot=new OvalSprite(1, 1);
   blueDot.setScale(0.1);
   blueDot.setLocation(
          random.nextDouble(),
          random.nextDouble());
   blueDot.setColor(Color.BLUE);

   scoreSprite=new StringSprite("Score: 0");
   scoreSprite.setHeight(0.1);
   scoreSprite.rightJustify();
   scoreSprite.topJustify();
   scoreSprite.setLocation(1, 0);
}

private void addSprites()
{
   canvas.addSprite(dot);
   canvas.addSprite(redDot);
   canvas.addSprite(blueDot);
   canvas.addSprite(scoreSprite);
}

Lines 46-50: makes the score sprite. Right justifying means the location will represent the rightmost location. Similarly top justifying means the location represents the topmost location. (1, 0) is the top right which is where the score will be. The text will be 1/10 of the screen high.

Line 58: adds the score sprite to the canvas to make it visible

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private int score;

Line 18: the integer which will keep the score

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public void startGame()
{
   score=0;
   makeSprites();
   addSprites();
}

private void makeSprites()
{
   dot=new OvalSprite(1, 1);
   dot.setScale(0.1);
   dot.setLocation(0.5, 0.5);
   dot.setColor(Color.RED);

   redDot=new OvalSprite(1, 1);
   redDot.setScale(0.1);
   redDot.setLocation(
          random.nextDouble(),
          random.nextDouble());
   redDot.setColor(Color.RED);

   blueDot=new OvalSprite(1, 1);
   blueDot.setScale(0.1);
   blueDot.setLocation(
          random.nextDouble(),
          random.nextDouble());
   blueDot.setColor(Color.BLUE);

   scoreSprite=new StringSprite("Score: "+score);
   scoreSprite.setHeight(0.1);
   scoreSprite.rightJustify();
   scoreSprite.topJustify();
   scoreSprite.setLocation(1, 0);
}
... code not shown
private void updateScore()
{
   scoreSprite.setText("Score: "+score);
}

private void handleCollisions()
{
   if(dot.intersects(blueDot))
   {
      repositionRandomly(blueDot);
      if(dot.getColor().equals(Color.BLUE))
      {
         dot.setColor(Color.RED);
         score++;
      }
      else
      {
         score--;
      }
      updateScore();
   }
   if(dot.intersects(redDot))
   {
      repositionRandomly(redDot);
      if(dot.getColor().equals(Color.RED))
      {
         dot.setColor(Color.BLUE);
         score++;
      }
      else
      {
         score--;
      }
      updateScore();
   }
}

Line 22: starts the score out at 0

Line ... : Don't type this line into your code.

Lines 48: initializes the score sprite using the score instance variable. You need to change this line to what it looks like here since originally it just made the score zero.

Lines 70-73: updates the score sprite to make sure it represents the current score

Lines 83, 87, 97, 101: changes the score when the dot intersects one of the colored dots. If the dot is the same color as the one intersected, then 1 is added to the score. If the dot is the opposite color of the one intersected, then 1 is subtracted from the score.

Lines 89, 103: when the int score changes, the StringSprite scoreSprite should change. These lines call the helper method to change the scoreSprite to represent the current score.

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private int timeLeft;
private StringSprite timerSprite;

Line 19: an integer representing the number of second left

Line 20: the StringSprite which will show the time left

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public void startGame()
{
   score=0;
   timeLeft=10;
   makeSprites();
   addSprites();
}

private void makeSprites()
{
   ... code not shown for brevity

   scoreSprite.setLocation(1, 0);

   timerSprite=new StringSprite("Timer: "+timeLeft);
   timerSprite.leftJustify();
   timerSprite.topJustify();
   timerSprite.setHeight(0.1);
   timerSprite.setLocation(0, 0);
}

private void addSprites()
{
   canvas.addSprite(dot);
   canvas.addSprite(redDot);
   canvas.addSprite(blueDot);
   canvas.addSprite(scoreSprite);
   canvas.addSprite(timerSprite);
}

private void updateTimer()
{
   timerSprite.setText("Timer: "+timeLeft);
}

Line 25: starts the timer out at 10

Line ... : Do not copy this line, just read it.

Lines 57-61: makes the timer sprite

Line 70: adds the timer sprite to the canvas to make it visible

Lines 73-76: updates the timer sprite to make sure it represents the current time

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public void startGame()
{
   score=0;
   timeLeft=10;
   makeSprites();
   addSprites();
   scheduleRelative(new TimeUpdater(), 1);
}

class TimeUpdater implements Alarm
{
   public void alarm()
   {
      timeLeft--;
      updateTimer();
      if(timeLeft>0)
      {
         scheduleRelative(this, 1);
      }
   }
}
... Code not shown
public void advanceFrame(double timePassed)
{
   if(timeLeft>0)
   {
       Point2D.Double mouse=
           getPlayer().getMouse().getLocation();
       dot.setLocation(mouse);
       handleCollisions();
   }
}

Line 28: schedules the alarm method of TimeUpdater to be called 1 second from the start of the game. Adding this line will cause an error until the class below in line 10-21 is copied into the class.

Lines 31-42: an inner class in Wackadot used to update the timeLeft.

Lines 33-41: the method called when the alarm goes off

Lines 37-40: if there is still time remaining, this schedules the alarm to go off again in 1 second

Line ... : Don't type this line into your code.

Lines 137-143: allows game control and scoring only while there is time left

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public void startGame()
{
   score=0;
   timeLeft=10;
   makeSprites();
   addSprites();
   scheduleRelative(new TimeUpdater(), 1);
   setHelpText("Lots of help text here later");
}

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import java.awt.geom;

/**This is a fun, simple game I made using
 * the FANG Engine.
 * @author Your Name Here
 */
public class Wackadot extends GameLoop
{

Lines 8-11: javadoc style comments. When you learn about how to use these, you can make web page documentation using the comments in your program.