creatyde-Intersections

Behold, the Intersections application!

Take a look at this handy gif for the best user experience:

Here is the code I used to create the Intersections project:

```var n = 100; // number of lines
var length = 300;
var windowLength = 720;
var widnowHeight = 480;
var radius = 20;

function getLine(x, y, angle) {
// compute halfways
var distX = sin(angle) * length/2;
var distY = cos(angle) * length/2;
return [x - distX, y - distY, x + distX, y + distY];
}

// using Paul Bourke's methodology
function intersection(x1,y1, x2,y2, x3,y3, x4,y4) {
// find denominator
var sd = (y4 - y3)*(x2 - x1)-(x4 - x3)*(y2 - y1);
if (sd == 0) return [-1, -1];
var sn = (x4 - x3)*(y1 - y3)-(y4 - y3)*(x1 - x3);
var s = sn/sd;
// first intersection point
var x = x1 + s*(x2 - x1);
var y = y1 + s*(y2 - y1);
// determine if point is within bounds (using x)
// not using y because sin/cos work weirdly for it
if (x >= x1 && x <= x2 && x >= x3 && x <= x4)
return [x, y];
// no intersection
return [-1, -1];
}

function click() {
// reset background
background('#fff2f2');
// save lines
var lineArray = [];
// generate n random lines, each of length 2 inches (black)
for (var i = 0; i < n; i++) {
var angle = random(0, PI);
var x = random(0, windowLength);
var y = random(0, windowHeight);
var l = getLine(x, y, angle);
append(lineArray, l);
}
// draw intersections
fill(255, 150, 150, 50);
strokeWeight(0);
for (var i = 0; i < n; i++) {
var line1 = lineArray[i];
for (var j = i+1; j < n; j++) {
var line2 = lineArray[j];
var inter = intersection(line1[0], line1[1],
line1[2], line1[3], line2[0],
line2[1], line2[2], line2[3]);
if (inter[0] > -1)
}
}
// draw lines
strokeWeight(2);
for (var i = 0; i < n; i++) {
var l = lineArray[i];
line(l[0], l[1], l[2], l[3]);
}
// done
}

function draw() {
if (mouseIsPressed) click();
}

function setup() {
createCanvas(windowLength, windowHeight);
background('#fff2f2');
stroke('#000000');
}
```