calling on classes to recognize an impact

General Discussion Other

adkins380

calling on classes to recognize an impact

in General Discussion • Other • 5 months ago

I am working on a game that has a few classes. I want the laser to recognize when it hits a meteor. I cannot figure out how to get the width of the meteors(array) and the laser(just a line) to see something like if( laser > meteor.width && laser < meteor.width). Something like that. I have the meteor in one class, and the laser in another, while moving it to a game class. One issue is that i am using mouseX for the laser position, and that I cant get any of the variables in so that i can have the impact. On an added note, i want the meteor to reset at the top if hit. Anyone know how to get this to work?

Replies(10)

quarks

Re: calling on classes to recognize an impact

5 months ago

If you consider the meteor to have a collision circle and if the laser is represented by a line then the problem resolves down to testing for a line-circle intersection.

I posted some code (a method) that performs a "line-circle intersection" test in this topic

PhiLho

Re: calling on classes to recognize an impact

5 months ago

Would rather be:
if (laser.x > meteor.x - meteor.width / 2 && laser.x < meteor.x + meteor.width / 2)
supposing the meteor position is its middle.

adkins380

Re: calling on classes to recognize an impact

5 months ago

i did that, which now it works kinda. Problem is that i had to call on the image trough the class. So it says meteor.meteorPic.width/2. And when i start it i test it with println("hit") and i get hits right from the start even when not shooting. Im not sure what is going on here

PhiLho

Re: calling on classes to recognize an impact

5 months ago

Add a condition: if (laser.isShooting && laser.x ...)

adkins380

Re: calling on classes to recognize an impact

5 months ago

i'm going to post my classes, im having troubles understanding why this isn't going to work.

I am trying to take the shooting class and the meteor class and put it into my game class so that it can run through that. Any suggestions? thank you

class Shoot
{
boolean shoot = false;
float a=680;
float sx = mouseX;
Shoot()
{
}
void shoot()
{
if (shoot)
{
laserdetail();
shoot = false;
}
}
void laserdetail()
{
stroke(0, 255, 0);
strokeWeight(5);
line(sx = mouseX, a, sx = mouseX, 0);
}
}

class Meteor
{
PImage meteorPic;
float[] mx;
float[] my;
float[] h;
float[] w;
float counter;
float metx = 0;
Meteor()
{
meteorPic = loadImage("meteor.png");
mx = new float[3];
my = new float[3];
h = new float[3];
w = new float[3];
counter =0.0;
for (int i = 0; i < 3; i++)
{
mx[i] = int(random(0, 600));
my[i] = int(random(-450, -50));
h[i] = 8;
w[i] = 8;
}
}
void displaymeteor()
{
for (int i = 0; i < 3; i++)
{
pushMatrix();
counter++;
translate(mx[i],my[i]);
rotate(counter*TWO_PI/360);
image(meteorPic, metx, 0, meteorPic.width/w[i]
, meteorPic.height/h[i]);
my[i] += 5;
if (my[i] > 850)
{
my[i] = my[i] % 850;
my[i] = int(random(-450, -50));
mx[i] = int(random(0, 600));
w[i] = int(random(6,10));
h[i] = int(random(6,10));
}
popMatrix();
}
}
}

class Game
{
Player player;
Meteor meteor;
Star star;
boolean startgame = false;
Menu menu;
boolean showmenu = true;
boolean restart = false;
Shoot shoot;
Game()
{
player = new Player();
meteor = new Meteor();
star = new Star();
menu = new Menu();
shoot = new Shoot();
}
void display()
{
button();
if (showmenu == true)
{
star.displayStar();
menu.displayMenu();
}
if (startgame==true)
{
star.displayStar();
s.shoot();
player.displayShip();
meteor.displaymeteor();
killMeteor();
}
}
void button()
{
if (mousePressed && mouseX > 250 && mouseX < 350 && mouseY > 320 && mouseY < 480)
{
showmenu = false;
startgame = true;
}
}
void killMeteor()
{
}
}

GoToLoop

Re: calling on classes to recognize an impact

5 months ago

There are some classes you haven't posted like Player, Star, Menu.

Also, I don't see any setup(), draw(), and sketch's field variables either!

You have to understand the dynamics of Processing go against strict OOP practices!

Any class you make have to interact w/ setup(), draw() and other input event functions like mousePressed()!

Resources like images, sound, video, and other data should be loaded once in setup(), for example.

B/c you don't want to generate useless redundant copies each time you instantiate a class!

Even worse if that happens in the middle of draw() callbacks!

The sketch itself is called the top-class, and ours are inner-classes of the top-class!

So generally you have to iterate over instantiated objects from within top-class's own draw() function!

P.S.: In short, you're trying to delegate to your inner-class Game,

features which should be normally stay within setup() & draw()!

Those other inner-classes should be declared on top of your sketch & instantiated within setup()!

adkins380

Re: calling on classes to recognize an impact

5 months ago

i didn't post the whole thing, it is pretty long. here is the rest.

Shoot s = new Shoot();
Game game;
void setup()
{
size(600, 800);
imageMode(CENTER);
game = new Game();
}
void draw()
{
background(0);
s.shoot();
game.display();
}
void mousePressed()
{
s.shoot = true;
}

class Menu
{
boolean menu = true;
PImage mmeteor;
int Mx, My;
Menu()
{
rectMode(CENTER);
mmeteor = loadImage("spaceship.png");
Mx = 0;
My = 0;
}
void displayMenu()
{
if (menu==true)
{
fill(0);
stroke(255);
rect(300, 400, 100, 80);
fill(0, 0, 255);
textAlign(CENTER, CENTER);
textSize(40);
text("Start", 300, 400);
pushMatrix();
rotate(radians(90));
translate(50, -50);
image(mmeteor, Mx, My, mmeteor.width/1.5, mmeteor.height/1.5);
My -= 5;
if (My < -900)
{
My = 200;
}
popMatrix();
}
}
}

class Player
{
PImage ship;
float x, y, shipx, shipy;
//boolean right = false;
//boolean left = false;
Player()
{
ship = loadImage("spaceship.png");
shipy = 680;
}
void displayShip()
{
image(ship, mouseX, shipy, ship.width/1.5, ship.height/1.5);
}
}

class Star
{
int[] xs;
int[] ys;
int[] starx;
int[] stary;
Star()
{
xs = new int[60];
ys = new int[60];
starx = new int[60];
stary = new int[60];
for (int i = 0; i < 60; i++)
{
xs[i] = int (random(0, 600));
ys[i] = int (random(0, 800));
starx[i] = int (random(1, 5));
stary[i] = int (random(1, 5));
}
}
void displayStar()
{
for (int i = 0; i < xs.length; i++)
{
fill(255);
noStroke();
ellipse(xs[i], ys[i], starx[i], stary[i]);
ys[i]++;
ys[i] = ys[i] % 800;
}
}
}

GoToLoop

Re: calling on classes to recognize an impact

5 months ago

I am trying to take the Shoot class and the Meteor class and put it into my Game class

so that they can run through that.

Inner-classes have access to anything from their top-class. In Processing case, the sketch itself is our top-class.

However, inner classes can't directly see each other!

Since inner-class Game is your inner-class wrapper now instead of Processing's top-class,

that is, where the other inner-classes are controlled from and iterated over;

you have to create a method there which iterates over each instance of Meteor,

to check whether each instance of Shoot collides to some Meteor's PImage dimensions!

For that, you're gonna need to pass Shoot instance coordinates to another method from Meteor class,

so an instance of Meteor can check whether it was hit or not!

GoToLoop

Re: calling on classes to recognize an impact

5 months ago

An alternative to have a static field to store a PImage once within your inner-classes which demands 1 of it:

Just make an abstract class w/ an PImage abstract field, and extends that to the class which needs it!

I'm gonna take Meteor inner-class as example for it:

static abstract class MeteorPic {
  static PImage meteorPic;
}

class Meteor extends MeteorPic {
  float[] mx, my;
  float[] h, w;
  float counter, metx;

  Meteor(PImage img) {
    meteorPic = img;
    
    mx = new float[3];
    my = new float[3];
    h  = new float[3];
    w  = new float[3];
    
    // ...

Don't forget to remove the PImage field within class Meteor itself,

since it's gonna use the static 1 inherented from abstract class MeteorPic instead!

Now within your wrapper inner-class Game's constructor,

pass loadImage() as argument for Meteor's constructor too:

  Game() {
    player = new Player( loadImage("spaceship.png") );
    meteor = new Meteor( loadImage("meteor.png") );
    menu   = new Menu( loadImage("spaceship.png") );

    star  = new Star();
    shoot = new Shoot();
  }

Doing so, you still have your PImage instances organized & encapsulated within their respective inner-classes,

but w/o making any costly redundant copies for each time they may be instantiated.

Since those inherented field variables, from their respective abstract inner-classes, are static now!

Of course, avoid instantiating inner-class Game more than once!

GoToLoop

Re: calling on classes to recognize an impact

5 months ago

Here's another style:

Since those PImage field variables are static,

we can access them directly w/o instantiating their respective class 1st!

So, no need to pass any PImage as argument to their constructors!

  Meteor() {
    mx = new float[3];
    my = new float[3];
    h  = new float[3];
    w  = new float[3];
    
    // ...

Just use loadImage() directly to those static fields of them:

  Game() {
    Player.ship = loadImage("spaceship.png");
    Meteor.meteorPic = loadImage("meteor.png");
    Menu.mmeteor = loadImage("spaceship.png");

    player = new Player();
    meteor = new Meteor();
    menu   = new Menu();
    star   = new Star();
    shoot  = new Shoot();
  }

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