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Greenfoot Video Tutorials
How to make things move in Greenfoot
Part I Keyboard Input Tutorial and Lesson
This is a work in progress
Some Useful Methods that Wombats can use
| Method |
Meaning |
public void act(){
if( Greenfoot.isKeyDown("left") )
System.out.println("left");
|
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| setRotation( 5) |
sets Wombat’s rotation to 5 |
| setRotation(getRotation() + 5) |
gets the Wombat’s current rotation + 5 setDirection(WEST); |
| canMove() |
returns a boolean that lets you know whether or not there is anything blocking the path of a Wombat, like the edge of the world etc.. |
| move() |
this a long method that does many things. Mainly though, if(canMove() == true) the wombat moves forward, otherwise it turns left |
| turnLeft() |
pretty self descriptive! |
Part III Assignments for my students
- Task #1) Modify the Wombat class so that it takes 30 steps and stops.
- Task #2) Modify the Wombat class so that every 4 steps that it makes it will turn left. Note: The wombat will still have to turn left if it hits a wall before taking 5 steps. Whenever the Wombat hits a wall, reset the number of steps to zero. Hint: Most of your modifications to this class should go in the act() method.
- Task #3) Modify the WOmbat class so that it only eats every other leaf that it finds.
- Task #4) Look at the TurnLeft() method, the code is reproduced below.. Make a similar method but that is called TurnRight()
public void turnLeft()
{
switch(direction) {
case SOUTH :
setDirection(EAST);
break;
case EAST :
setDirection(NORTH);
break;
case NORTH :
setDirection(WEST);
break;
case WEST :
setDirection(SOUTH);
break;
}
}
- Task#5) Create a wombat that makes 2 steps and tries to turn in a random direction
(up,down,left or right).
- Her's how to create random numbers in java
How to Change a double to an int
double myDouble = 1.4;
int myInt = (int) myDouble; // (int) 'casts' the data to an int
How to Create a Random int
double randD = Math.random(); //between 0 and .99999999
//flipACoin is always either 1 or 2
//because .999 * 2 = 1.99800 which becomes 1 if we're dealing with an int
int flipACoin = (int)(randD *2); //multiply by 2, truncate
int oneThroughThree= (int) (randD *2 + 1);
Move on to the next lesson and Labs
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Graphing Calc
