tesh-Intersections

Here’s the sketch:

Here’s the GIF:

tesh-Intersections

And here’s my code!

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var lines = [];
var lines = [];
var numLines = 12;
var len = 240;
var intSize = 30;
var bg = 200;
 
var xborder = len/2;
var yborder = len/5;
 
//Intersection variables
var intx = 0.0;
var inty = 0.0;
 
function setup() { 
  createCanvas(720, 480);
  fill('rgba(180,243,255, 0.35)')
  background(bg);
} 
 
function draw() {
 
  background(bg);
  if(lines.length > 1){
  	for(var i=0; i<numLines; i++){
      var x1 = lines[i][0];
      var y1 = lines[i][1];
      var x2 = lines[i][2];
      var y2 = lines[i][3];
 
 
      for(var j=0; j<numLines; j++){
      if(j!=i){
      var x3 = lines[j][0];
      var y3 = lines[j][1];
      var x4 = lines[j][2];
      var y4 = lines[j][3];
 
      intx = 0.0;
      inty = 0.0;
 
      intersectionPt(x1,x2,x3,x4,y1,y2,y3,y4,intx,inty)
      if (intx > 0 && inty > 0){
            noStroke();
            ellipse(intx,inty,intSize,intSize);
          }
        }
 
      stroke(0);
      line(x1,y1,x2,y2);
      }
 
    }
  }
}
 
//Generates random lines whenever the mouse is clicked
function mousePressed(){
  lines = [];
 
  for(var i=0; i<numLines; i++){
    var x1 = random(xborder,width-xborder);
    var y1 = random(height-yborder);
    var x2 = random(x1-len,x1+len);
    var y2 = sqrt(sq(len) - sq(x2-x1))+y1; 
 
    lines.push([x1,y1,x2,y2]);
  }
}
 
 
//Code heavily taken from Example Code and Explanations by Paul Bourke at http://paulbourke.net/geometry/pointlineplane/
//
//Function to test for intersections between line segments:
function intersectionPt(x1,x2,x3,x4,y1,y2,y3,y4){
 
	var uA,uB;
  var den,numA,numB;
 
  den  = (y4-y3) * (x2-x1) - (x4-x3) * (y2-y1);
  numA = (x4-x3) * (y1-y3) - (y4-y3) * (x1-x3);
  numB = (x2-x1) * (y1-y3) - (y2-y1) * (x1-x3);
 
  //Coincident? - If true, displays intersection in center of line segment
   if (abs(numA) == 0 && abs(numB) == 0 && abs(den) == 0) {
      intx = (x1 + x2) / 2;
      inty = (y1 + y2) / 2;
      return(true);
   }
 
   //Parallel? - No intersection
   if (abs(den) == 0) {
      intx = 0;
      inty = 0;
      return(false);
   }
 
   //Intersection?
   uA = numA / den;
   uB = numB / den;
 
   //If both lie w/in the range of 0 to 1 then the intersection point is within both line segments.
   if (uA < 0 || uA > 1 || uB < 0 || uB > 1) {
      intx = 0;
      inty = 0;
      return(false);
   }
   intx = x1 + uA * (x2 - x1);
   inty = y1 + uA * (y2 - y1);
   return(true);
}