miyehn-Intersections

var lineNum = 12;
var lines;
var intersections;
 
function setup() {
	createCanvas(720,480);
	noLoop();
}
 
function draw() {
	background(255);
	stroke(0);
	strokeWeight(1);
	lines = new Array();
	intersections = new Array();
	for(var i=0; i<lineNum; i++) {
		lines.push(new Line);
	}
	//console.log(lines);
	//display lines and calculate intersections
	for(var i=0; i<lineNum; i++) {
		lines[i].display();
		for(var j=i+1; j<lineNum; j++) {
			var l1 = lines[i]; var l2 = lines[j];
			var x = (l2.b-l1.b)/(l1.m-l2.m);
			if (x>=l1.p.x && x<=l1.q.x &&
			    x>=l2.p.x && x<=l2.q.x) {
				intersections.push(createVector(x, l1.m*x+l1.b));
			}
		}
	}
	//display intersections
	fill(255,100,100,100);
	noStroke();
	for(var i=0; i<intersections.length; i++) {
		ellipse(intersections[i].x,intersections[i].y,10,10);
	}
 
}
 
function mouseClicked() {
	redraw();
}
 
class Line {
	constructor() {
		this.p = createVector(random(0,width),random(0,height));
		this.q = createVector(random(0,width),random(0,height));
		//this is to make sure p always holds the coord of the point on the left.
		if(this.p.x>this.q.x) {
			var tmp = this.p;
			this.p = this.q;
			this.q = tmp;
		}
		this.m = (this.q.y-this.p.y)/(this.q.x-this.p.x);
		this.b = this.p.y-(this.m * this.p.x);
	}
 
	display() {
		line(this.p.x,this.p.y,this.q.x,this.q.y);
	}
}