Shared Data

Gail Carmichael

gail_c@scs.carleton.ca

Please Download:

www.scs.carleton.ca/~gail_c/comp1005/Robots1.zip

www.scs.carleton.ca/~gail_c/comp1005/Birds1.zip

About Me

Sharing Resources

http://www.flickr.com/photos/marcosbessa/6260425373/

familyCar = new Car(“black”);

mom.car = familyCar;dad.car = familyCar;teen.car = familyCar;

teen.car.crash();

// Now the family car is not drivable!if (!mom.car.drivable()) mom.isStranded();if (!dad.car.drivable()) dad.isStranded();

Robots Example

Examine code in

Robots1.pde

www.scs.carleton.ca/~gail_c/comp1005/Robots1.zip

Robot

Robot

Robot

Beacon

Beacon

Beacon

Pros and cons?

Let’s add movement

(demo first)

Step 1:

Trigonometry to move forward in current direction

x = x + speed * cos(direction)

y = y + speed * sin(direction)

Step 2:

Change direction to head for beacon

crossProduct = (r'x - rx)(gy - ry) - (r'y - ry)(gx - rx)

Step 3:

Add random error for realism

amountToTurn = θ + random(θ/4) - (θ/4)/2

Try implementing the move() method…

x = x + speed * cos(direction)

y = y + speed * sin(direction)

crossProduct = (r'x - rx)(gy - ry) - (r'y - ry)(gx - rx)

positive → left hand turn

negative → right hand turn

amountToTurn = θ + random(θ/4) - (θ/4)/2

Let’s add drag-and-drop for the beacons

(demo first)

www.scs.carleton.ca/~gail_c/comp1005/Robots2.zip

What if we want multiple robots per beacon?

www.scs.carleton.ca/~gail_c/comp1005/Robots3.zip

Robot

Robot

Robot

Beacon

Beacon

Implement multiple robots per beacon.

Bird Animation Example

Please Download:

www.scs.carleton.ca/~gail_c/comp1005/Birds1.zip

Study the code, run the program.

How is the data in the program set up?

Pros and cons?

Where can data be shared?

Implement sharing so each bird points to the same set of animation frames.

Separating Shared Data

Person molly = new Person(“Molly”);Person henry = new Person(“Henry”);

Person[] personList = new Person[2];

personList[0] = molly;personList[1] = henry;

Person[] personListCopy = new Person[2];

for (int i=0; i < personList.length; i++){ personListCopy[i] = personList[i];}

personListCopy[0].name = “Mallory”;

// Prints MallorySystem.out.println(personList[0].name);

Person[] personListCopy = new Person[2];

for (int i=0; i < personList.length; i++){ personListCopy[i] = new Person(personList[i].name);}

personListCopy[1].name = “Harry”;

// Still prints Henry since it’s unchangedSystem.out.println(personList[1].name);

Shallow Copies

vs

Deep Copies

Thanks!

Gail Carmichael

gail_c@scs.carleton.ca