// When you press the 'F' key, this program will export a series of images into

// your default Downloads folder. These can then be made into an animated gif. 

// This code is known to work with p5.js version 0.6.0

// Prof. Golan Levin, 28 January 2018

​

// INSTRUCTIONS FOR EXPORTING FRAMES (from which to make a GIF): 

// 1. Run a local server, using instructions from here:

//    https://github.com/processing/p5.js/wiki/Local-server

// 2. Set the bEnableExport variable to true.

// 3. Set the myNickname variable to your name.

// 4. Run the program from Chrome, press 'f'. 

//    Look in your 'Downloads' folder for the generated frames.

// 5. Note: Retina screens may export frames at twice the resolution.

​

​

//===================================================

// User-modifiable global variables. 

var myNickname = "nickname";

var nFramesInLoop = 60;

var bEnableExport = true;

​

// Other global variables you don't need to touch.

var nElapsedFrames;

var bRecording;

var theCanvas;

​

//===================================================

function setup() {

  theCanvas = createCanvas(400, 400);

  bRecording = false;

  nElapsedFrames = 0;

}

​

//===================================================

function keyTyped() {

  if (bEnableExport) {

    if ((key === 'f') || (key === 'F')) {

      bRecording = true;

      frameRate(2); // while we're exporting

      nElapsedFrames = 0;

    }

  }

}

​

//===================================================

function draw() {

​

  // Compute a percentage (0...1) representing where we are in the loop.

  var percentCompleteFraction = 0;

  if (bRecording) {

    percentCompleteFraction = float(nElapsedFrames) / float(nFramesInLoop);

  } else {

    percentCompleteFraction = float(frameCount % nFramesInLoop) / float(nFramesInLoop);

  }

​

  // Render the design, based on that percentage. 

  // This function renderMyDesign() is the one for you to change. 

  renderMyDesign(percentCompleteFraction);

​

  // If we're recording the output, save the frame to a file. 

  // Note that the output images may be 2x large if you have a Retina mac. 

  // You can compile these frames into an animated GIF using a tool like: 

  if (bRecording && bEnableExport) {

    var frameOutputFilename = myNickname + "_frame_" + nf(nElapsedFrames, 4) + ".png";

    print("Saving output image: " + frameOutputFilename);

    saveCanvas(theCanvas, frameOutputFilename, 'png');

    nElapsedFrames++;

​

    if (nElapsedFrames >= nFramesInLoop) {

      bRecording = false;

      frameRate(60);

    }

  }

}

​

//===================================================

function renderMyDesign(percent) {

  //

  // THIS IS WHERE YOUR ART GOES. 

  // This is an example of a function that renders a temporally looping design. 

  // It takes a "percent", between 0 and 1, indicating where we are in the loop. 

  // Use, modify, or delete whatever you prefer from this example. 

  // This example uses several different graphical techniques. 

  // Remember to SKETCH FIRST!

​

  //----------------------

  // here, I set the background and some other graphical properties

  background(0,100);

  smooth();

  stroke(0, 0, 0);

  strokeWeight(2);

  translate(width/2, height/2);

  rotate(radians(frameCount*2));

  push();

  let radius = width / 6;

​

  for (let i = radius; i > 0; i -= 1) {

    for (let j = 0; j < 5; j++) {

      push();

      colorMode(HSB, 100);

      ellipseMode(CORNER);

      rotate(TWO_PI * j / 5);

      let hue = map(i, 0, radius, 40, 100);

      stroke(hue, 100, 100);

      fill(hue, 100, 100);

      ellipse(0, 0, i);

      pop();

​

      // center of the flower

      colorMode(RGB, 255);

      ellipseMode(CENTER);

      noStroke();

      fill(240, 80,0);

      ellipse(0, 0, width / 26);

    }

  }

  pop();

}

​

// Symmetric double-element sigmoid function ('_a' is the slope)

// See https://github.com/IDMNYU/p5.js-func/blob/master/lib/p5.func.js

// From: https://idmnyu.github.io/p5.js-func/

//===================================================

function doubleExponentialSigmoid(_x, _a) {

  if (!_a) _a = 0.75; // default

​

  var min_param_a = 0.0 + Number.EPSILON;

  var max_param_a = 1.0 - Number.EPSILON;

  _a = constrain(_a, min_param_a, max_param_a);

  _a = 1 - _a;

​

  var _y = 0;

  if (_x <= 0.5) {

    _y = (pow(2.0 * _x, 1.0 / _a)) / 2.0;

  } else {

    _y = 1.0 - (pow(2.0 * (1.0 - _x), 1.0 / _a)) / 2.0;

  }

  return (_y);

}