2017.10.03 -- ICM Week 4

gistfile1.txt

//why are the magnets getting stuck on the walls?
//slicing while looping?
//having an object perform certain functions on itself?  maintenance functions?

let magnets = [];


function setup() {
	createCanvas(600, 500);
}


function draw() {
	background(220, 120, 30);

	//iterate through array of magnets (balls) and ask each ball to display, move, and bounce
	for (let i = 0; i < magnets.length; i++) {
		magnets[i].display();
		magnets[i].move();
		magnets[i].bounce();
		//remove a magnet object if it is close to its 'birthplace' and age is over ten frames (so that they have a chance to exist)
		if (magnets[i].isHome() && (frameCount - magnets[i].birth) > 10) {
			magnets.splice(i, 1);
			//is the following line necessary?
			i--;
		}
	}

	//reverse speed every 200 frames
	if (frameCount % 200 == 0) {
		for (let i = 0; i < magnets.length; i++) {
			magnets[i].reverse();
		}
	}
}


//create a new ball every time the mouse is clicked 
function mouseClicked() {
	magnets.push(new Magnet(mouseX, mouseY, 25));
}


//constructor function for magnet objects
function Magnet(x, y, d) {

	this.x = x;
	this.y = y;
	this.d = d;

	//used to prevent balls from disappearing immediately after being 'born'
	this.birth = frameCount;
	
	//used to keep track of where they were 'born' and should disappear
	this.birthX = x;
	this.birthY = y;

	this.xspeed = random(-5, 5);
	this.yspeed = random(-5, 5);

	this.move = function() {
		this.x += this.xspeed;
		this.y += this.yspeed;
	}

	//attempt to add gravity... didn't work...
	this.updateSpeed = function() {
		this.yspeed += (1 / 60 * 10 * (frameCount - this.birth));
		console.log(frameCount - this.birth);
	}

	//bounces the object against the walls
	this.bounce = function() {
		if (this.x - this.d / 2 <= 0 || this.x + this.d / 2 >= width) {
			this.xspeed *= -1;
		}
		if (this.y - this.d / 2 < 0 || this.y + this.d / 2 > height) {
			this.yspeed *= -1;
		}
	}

	//reverse speed
	this.reverse = function() {
		this.xspeed *= -1;
		this.yspeed *= -1;
	}


	//displays the magnet object as an ellipse
	this.display = function() {
		fill(255, 0, 255);
		ellipse(this.x, this.y, this.d, this.d);
	}

	//attempt at a repelling function, but how to access other objects in the array magnets[]? didn't work...
	this.repel = function(magnet) {
		if (dist(this.x, this.y, magnet.x, magnet.y) < 50) {
			this.xspeed = -magnet.xspeed;
			this.yspeed = -magnet.yspeed;
		}
	}


	//returns whether the magnet is close (within 10) to home
	this.isHome = function() {
		if (dist(this.x, this.y, this.birthX, this.birthY) < 10) {
			return true;
		} else {
			return false;
		}
	}
}