A Pen By
Jacek

JavaScript preprocessors can help make authoring JavaScript easier and more convenient. For instance, CoffeeScript can help prevent easy-to-make mistakes and offer a cleaner syntax and Babel can bring ECMAScript 6 features to browsers that only support ECMAScript 5.

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` ````
// Daniel Shiffman
// http://youtube.com/thecodingtrain
// http://codingtra.in
// Recaman Sequence
// https://youtu.be/DhFZfzOvNTU
let numbers = [];
let count = 1;
let sequence = [];
let index = 0;
//how long between a new number is generated
let newTickEveryMS=1000
let oldTickTime=Date.now()
let currStep
let scl = 0;
let arcs = [];
let biggest = 0;
class Arc {
constructor(start, end, dir) {
this.start = start;
this.end = end;
this.dir = dir;
}
show() {
let diameter = abs(this.end - this.start);
let x = (this.end + this.start) / 2;
stroke(255);
strokeWeight(0.5);
noFill();
if (this.dir == 0) {
//TOP
arc(x, 0, diameter, diameter, PI, 0);
} else {
//BOTTOM
arc(x, 0, diameter, diameter, 0, PI);
}
}
showPartial(){
stroke(255);
strokeWeight(0.5);
noFill();
let diameter = abs(this.end - this.start);
let x = (this.end + this.start) / 2;
if (this.dir == 0) {
//TOP
if(this.end<this.start){
drawLeftTop(x,0,diameter,currStep)
}
else{
drawRightTop(x,0,diameter,currStep)
}
} else {
//BOTTOM
if(this.end<this.start){
drawLeftBottom(x,0,diameter,currStep)
}
else{
drawRightBottom(x,0,diameter,currStep)
}
}
}
}
function setup() {
createCanvas(windowWidth, windowHeight);
frameRate(30);
background(0);
numbers[index] = true;
sequence.push(index);
}
function step() {
let next = index - count;
if (next < 0 || numbers[next]) {
next = index + count;
}
numbers[next] = true;
sequence.push(next);
let a = new Arc(index, next, count % 2);
arcs.push(a);
index = next;
if (index > biggest) {
biggest = index;
}
count++;
}
function draw() {
if (oldTickTime < Date.now()) {
step()
oldTickTime = Date.now() + newTickEveryMS;
//when did the new tick start
start=Date.now()
//when is it going to end
end=start+newTickEveryMS
}
// at what point in the tick are we? map that to radians
// v if this is 0 there phantom arcs appearing for a few frames
currStep=map(end-Date.now(),newTickEveryMS,0, 0.1 ,PI)
translate(0, height / 2);
scl = lerp(scl, width / (biggest*1.1), 0.1);
scale(scl);
background(0);
for(let i=0;i<arcs.length-1;i++){
arcs[i].show()
}
arcs[arcs.length-1].showPartial()
// if (count > windowWidth) {
// noLoop();
// }
}
/**
* drawing functions
* naming scheme
* draw[direction it is going on x axis][direction on y axis]()
*/
function drawRightBottom(x,y,diameter,currStep) {
arc(x, y, diameter, diameter, PI - currStep, PI);
}
function drawRightTop(x,y,diameter,currStep) {
arc(x, y, diameter, diameter, PI, currStep - PI);
}
function drawLeftBottom(x,y,diameter,currStep) {
arc(x, y, diameter, diameter, 0, currStep);
}
function drawLeftTop(x,y,diameter,currStep) {
arc(x, y, diameter, diameter, 0 - currStep, 0);
}
```

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