​

let s = 800;

let width = s;

let ratio = 1;

let height = width*ratio;

​

​

let sliderZoom;

let sliderXAxis;

let sliderYAxis;

​

let complexPlaneLeft = -2;

let complexPlaneRight = 0.6;

let complexPlaneBottom = -1.3*ratio;

let complexPlaneTop = 1.3*ratio;

​

​

function setup() {

  createCanvas(width, height);

  background(255);

  pixelDensity(1);

  sliderZoom = createSlider(1, 10, 1, 0.2);

  sliderZoom.position(0, height + 30);

  sliderZoom.style('width', width + 'px');

  sliderXAxis = createSlider(complexPlaneLeft, complexPlaneRight, 0, 0.00001);

  sliderXAxis.position(0, height);

  sliderXAxis.style('width', width + 'px');

  sliderYAxis = createSlider(complexPlaneBottom, complexPlaneTop, 0, 0.00001);

  sliderYAxis.position(width + 20, 0);

  sliderYAxis.style('width', height + 'px');

  sliderYAxis.style('transform-origin', '0 0');

  sliderYAxis.style('transform', 'rotate(90deg)');

  button = createButton('Toggle Coordinates');

  button.position(width/2 - 25, height + 60);

  button.mousePressed(() => {

    drawCoordinates = !drawCoordinates

  });

  doit();

}

​

​

​

function doit(){

  resetMatrix();

  loadPixels();

  let zoom = sliderZoom.value();

  let xOffset = sliderXAxis.value();

  let yOffset = sliderYAxis.value();

  for(let k = 0; k < width; k++) {

      for(let l = 0; l < height; l++) {

        let xMin = complexPlaneLeft / zoom + xOffset;

        let xMax = complexPlaneRight / zoom + xOffset;

        let x = map(k, 0, width, xMin, xMax);

        let yMin = complexPlaneBottom / zoom + yOffset;

        let yMax = complexPlaneTop / zoom + yOffset;

        let y = map(l, 0, height, yMin, yMax);

        fastMandelbrot(x, y, (l*width+k)*4);

        //let c = new Complex(x, y);        

        //mandelbrot(c, k, l);

      }

  }

  updatePixels();

  if(drawCoordinates) {

    drawPlane();

  }

}

​

​

​

var iterations = 800;

var magic_num = 4;

function mandelbrot(c, k, l) {

​

  let z = new Complex(0, 0);

  let i;

  for(i = 0; i < iterations; i++) {

    z = z.multiply(z).add(c);

    if(z.r > magic_num || z.i > magic_num || -z.r > magic_num || -z.i > magic_num) {

      break;

    }

  }

  let index = (l*width+k)*4;  

  if(i != iterations){

    pixels[index + 0] = (i/iterations)*255*10;

    pixels[index + 1] = pixels[index + 0];

    pixels[index + 2] = pixels[index + 0];

  } 

  pixels[index + 3] = 255;

}

​

function fastMandelbrot(cR, cI, index) {

​

  let zR = 0;

  let zI = 0;

  let i;

  for(i = 0; i < iterations; i++) {

    let tempZr = zR;

    zR = (zR * zR - zI * zI) + cR;

    zI = 2*tempZr*zI + cI;

    if(zR > magic_num || zI > magic_num || -zR > magic_num || -zI > magic_num) {

      break;

    }

  }

  if(i != iterations){

    pixels[index + 0] = (i/iterations)*255*10;

    pixels[index + 1] = pixels[index + 0];

    pixels[index + 2] = pixels[index + 0];

  } 

  pixels[index + 3] = 255;

}

​

function mouseClicked() {

  background(0);

  doit();

}

​

​

function drawPlane() {

    stroke("red");

    let xZero = map(0, complexPlaneLeft, complexPlaneRight, 0, width);

    let yZero = map(0, complexPlaneBottom, complexPlaneTop, 0, width);

    let zoom = sliderZoom.value();

    let xOffset = sliderXAxis.value();

    let yOffset = sliderYAxis.value();

    let xMin = complexPlaneLeft / zoom + xOffset;

    let xMax = complexPlaneRight / zoom + xOffset;    

    let yMin = complexPlaneBottom / zoom + yOffset;

    let yMax = complexPlaneTop / zoom + yOffset;

    let middleX = map(0, xMin, xMax, 0, height);  

    let zeroX = map(0, xMin, xMax, 0, width);

    let oneX =  map(1, xMin, xMax, 0, width);

    let nOneX = map(-1, xMin, xMax, 0, width);

    let nTwoX =  map(-2, xMin, xMax, 0, width);

    let middleY = map(0, yMin, yMax, 0, height);

    let i = map(1, yMin, yMax, 0, height);

    let nI = map(-1, yMin, yMax, 0, height);

    strokeWeight(0.5);

    noFill();

    line(0, middleY, width, middleY);

    line(middleX, 0, middleX, height);

​

    strokeWeight(1);

    textAlign(CENTER, CENTER);

    fill("red");

    text("1", oneX, middleY);

    text("0", zeroX, middleY);

    text("-1", nOneX, middleY);

    text("-2", nTwoX, middleY);

    text("    i", middleX, i);

    text("    -i", middleX, nI);

}

​

​