Making a simple game using OOP

Programming Questions

nessdan

Making a simple game using OOP

in Programming Questions • 2 years ago

So, I'm starting to try and program games and use Object Oriented Programming while doing it. Processing has been great so far with it's ease of use and me not having to worry about making a game loop, etc. but I hit a wall and I'm not sure how to do this (or how I should properly do this to be more accurate.)

So here is the game and the (little) progress I have made:

http://www.openprocessing.org/visuals/?visualID=41407

Since I'm relatively new to game programming and OOP, I've been a bit confused (as you can tell from my code comments). What I want to be able to implement next is a click event (I know how to do that...) that will cause the player class to call shoot() which will create a new Bullet object (I'm a bit iffy on this and whether that's right) and lastly, have the bullet actually update and draw on screen.

While reviewing my code, I feel like I've messed up my draw method by putting in myPlayer methods. Should I have a broader umbrella method that updates all classes? I'm not even sure how I could do that but that's just what my brainstorming came up with.

So... How do I go about doing this? Am I doing this right or am I way off?

Replies(5)

Evrim Ozt..

Re: Making a simple game using OOP

2 years ago

Use an arraylist;

List<Bullet> bullets;

// in setup()

bullets = new ArrayList<Bullet>();

// in draw() or update(), whichever you use

for (Iterator bulletsit = bullets.iterator(); bulletsit.hasNext(); ) {

Bullet bulleto = (Bullet) bulletsit.next();

bulleto.draw() // your draw function

}

nessdan

Re: Making a simple game using OOP

2 years ago

Thank you! I ended up finding an example on openprocessing.org so that helped a lot as well (and it was very similar to your solution.)

One extra thing I'd like to say: I ended up adding two methods to the Player and Bullet class: update and display. Update handles the logic (detect collisions, etc.) and display draws it (draw image on the updated position). I'm very happy with this model :)

In the end, this is what my code looked like (Note: I'm only showing the added code; there is obviously a lot more code):

/* Global Variables */
ArrayList theBullets;
void setup() {
theBullets = new ArrayList();
}
void draw() {
myPlayer.update();
myPlayer.display();
for(int i = 0; i < theBullets.size(); i++) {
Bullet b = (Bullet)theBullets.get(i);
b.update();
b.display();
}
}

Of course, there's a lot more code behind the scenes. If you anyone would like to see the code, you can over here. It's a lot neater then it was before :)

Thanks for all the help!

bustup

Re: Making a simple game using OOP

2 years ago

On a sidenote, you should always specify what kind of object the ArrayList hold. Like brokkoli said.

/* Global Variables */
ArrayList<Bullet> theBullets;
void setup() {
theBullets = new ArrayList<Bullet>();
}
void draw() {
myPlayer.update();
myPlayer.display();
for(int i = 0; i < theBullets.size(); i++) {
Bullet b = theBullets.get(i);
b.update();
b.display();
}
}

amnon.owed

Re: Making a simple game using OOP

2 years ago

You're making some very good progress Daniel. Your second code is a lot cleaner. One minor remark though. You can remove a lot of this or myPlayer references in your classes. You've added them almost everywhere, but they are required almost nowhere. So save yourself some typing. ;-)

For example the Bullet's stillAlive() function could be shortened to this:

void stillAlive() {
if (location.y > height || location.y < 0 || location.x > width || location.x < 0) { theBullets.remove(this); }
}

nessdan

Re: Making a simple game using OOP

2 years ago

bustup, I'll follow what you guys said about that, but I'm a bit confused on what adding that does. I went to the ArrayList reference guide but couldn't find anything about "ArrayList<>()". Could you explain what that did?

And thanks amnon.owed, I removed all the "this"s and "myPlayer"s where they were unnecessary :) (I also refactored the code like you posted above and gave you a shout-out in the code comments - thanks!)

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