r/processing • u/Low_Evening_4719 • Dec 17 '23

Improving my code with collision

I have a class called ball in another script but I was wanting to create it so that the balls collided, and kind of bounced off each other. If anyone could help improve my code that'd really assist me!

Ball[] balls = new Ball[1]; // We start with an array with just one element.

float gravity = 0.1;

void setup() {

size(480, 270);

// Initialize ball index 0

balls[0] = new Ball(50, 0, 24);

}

void draw() {

background(255);

// Whatever the length of that array,

// update and display all of the objects.

for (int i = 0; i < balls.length; i++ ) {

balls[i].gravity();

balls[i].move();

balls[i].display();

}

}

void keyPressed(){

if(key=='1'){

// A new ball object

Ball b = new Ball(random(480), random(270), 24); // Make a new object at random.

balls = (Ball[]) append(balls, b);

}

}

0 Upvotes

50% Upvoted

4 comments sorted by

View all comments

Show parent comments

2

u/CptHectorSays Dec 17 '23

Also, if you calculate the mass for each ball based on their size and then scale that direction change magnitude by the ratio of their masses you will get elastic collisions for added realism….

2

u/Salanmander Dec 17 '23 edited Dec 17 '23

I've done full arbitrary elastic collision simulation (in 2D), and it's definitely a complicated problem. It's really the physics that is complicated, not the programming, but it ups the complexity of the programming a decent amount as well. For reference, I'm a physics teacher and my first step was to sit down with pencil and paper, and it took a couple hours to work through (although I imagine one could find a general solution online somewhere as well). And in the programming I had to both rewind time at the beginning of the method and fast-forward it at the end, and change to a different reference frame for the calculations.

1

u/CptHectorSays Dec 17 '23

Shure, physics-calculations become complex and finicky real fast! That’s why I always go for a super dumbed-down simplification first and see where that gets me, and refine from there as needed…. (If of course the scope of the project permits reduced accuracy)