Getting 2 arrays of objects to interact.

Programming Questions

gravygeys..

Getting 2 arrays of objects to interact.

in Programming Questions • 1 years ago

I'm trying to make a space invaders type program. So I have an array of bullets from the ship and an array of enemies. I have a boolean function in the Bullet class, but I'm not sure how to test it against all of the other enemies. Sorry if this seems confusing. Here's my code. (O line 63, where i wrote " HERE IS WHERE I NEED HELP!!" is where i think i need help. haha)

Timer timer;
Bullet[] bullets;
int xBullet, yBullet;
int r;
int totalBullets = 0;
Enemy[] enemies;
int totalEnemies = 0;
void setup() {
size(600, 600);
smooth();
background(0);
enemies = new Enemy[1000];
bullets = new Bullet[5000];
timer = new Timer(300); // Create a timer that goes off every 2 seconds
timer.start(); // Starting the timer
}
void draw() {
if (frameCount == 10) {
// delay(1000);
}
fill(0, 10);
rect(0, 0, 600, 600);
//ENEMIES
// Check the timer
if (timer.isFinished()) {
// Deal with enemies
// Initialize one enemy
enemies[totalEnemies] = new Enemy();
// Increment totalEnemies
totalEnemies ++ ;
// If we hit the end of the array
if (totalEnemies >= enemies.length) {
totalEnemies = 0; // Start over
}
timer.start();
}
// Move and display all enemies
for (int i = 0; i < totalEnemies; i++ ) {
enemies[i].move();
enemies[i].display();
}
//BULLETS
bullets[totalBullets] = new Bullet();
if (totalBullets >= bullets.length) {
totalBullets = 0;
}
for (int i = 0; i <= totalBullets; i++) {
bullets[i].shoot();
bullets[i].display();
println("here");
if (bullets[i].hit(enemies[HERE IS WHERE I NEED HELP!!])) {
println("HIIIIT");
}
//println(bullets[0].yBullet);
}
}
void keyReleased() {
bullets[totalBullets].shoot();
totalBullets++;
println("keyPressed " + "Bullet #" + totalBullets);
}
class Bullet {
float x, y;
float r;
Bullet() {
y = 580;
x = mouseX;
r = 5;
}
void display() {
ellipseMode(CENTER);
ellipse(x, y, r, r*2);
}
void shoot() {
y -= 10;
}
// A function that returns true or false based on
// if the catcher intersects a raindrop
boolean hit(Enemy d) {
// Calculate distance
float distance = dist(x,y,d.x,d.y);
// Compare distance to sum of radii
if (distance < r + d.r) {
return true;
} else {
return false;
}
}
}
// Learning Processing
// Daniel Shiffman
// http://www.learningprocessing.com
// Example 10-10: The rainEnemy catching game
class Enemy {
float x,y; // Variables for location of rainEnemy
float speed; // Speed of rainEnemy
color c;
float r; // Radius of rainEnemy
Enemy() {
r = 8; // All rainEnemys are the same size
x = random(width); // Start with a random x location
y = -r*4; // Start a little above the window
speed = random(1,5); // Pick a random speed
c = color(50,100,150); // Color
}
// Move the rainEnemy down
void move() {
// Increment by speed
y += speed;
}
// Check if it hits the bottom
boolean reachedBottom() {
// If we go a little beyond the bottom
if (y > height + r*4) {
return true;
} else {
return false;
}
}
// Display the rainEnemy
void display() {
// Display the Enemy
fill(c);
noStroke();
for (int i = 2; i < r; i++ ) {
ellipse(x,y + i*4,i*2,i*2);
}
}
// If the Enemy is caught
void caught() {
// Stop it from moving by setting speed equal to zero
speed = 0;
// Set the location to somewhere way off-screen
y = - 1000;
}
}

Replies(1)

calsign

Re: Getting 2 arrays of objects to interact.

1 years ago

To start, there are already numerous Space Invaders threads, particularly on the old forum.

The simplest way to detect collisions between two arrays of Objects is to create a nested for loop.
For example,

for(int i = 0; i < array1.length; i ++) {
      for(int j = 0; j < array2.length; j ++) {
            //Now here, check for collision with array1[i] and array 2[j]
      }
}

In your case, you would replace array1 with Bullets (which you have) and nest a for loop cycling array2, replaced with Enemies.

I'll leave it up to you to implement this.

And, what exactly is a Timer?

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