// 

// M_1_5_02

//

// Generative Gestaltung – Creative Coding im Web

// ISBN: 978-3-87439-902-9, First Edition, Hermann Schmidt, Mainz, 2018

// Benedikt Groß, Hartmut Bohnacker, Julia Laub, Claudius Lazzeroni

// with contributions by Joey Lee and Niels Poldervaart

// Copyright 2018

//

// http://www.generative-gestaltung.de

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

​

'use strict';

​

var minus;

var plus;

​

var sketch = function( p ) {

  var agents = [];

  var agentCount = 5000;

  var overlayAlpha = 5;

  var strokeWidth = 1.5;

​

  minus = p.createVector(p.windowWidth * 0.5, p.windowHeight*0.33);

  plus  = p.createVector(p.windowWidth * 0.5, p.windowHeight*0.66);

  p.setup = function() {

    p.createCanvas(p.windowWidth, p.windowHeight);

    p.colorMode('RGB', 255);

​

    for(var i = 0; i < agentCount; i++) {

      agents[i] = new Agent();

    }

  }

​

  p.draw = function() {

    p.fill(0, 0, 25, overlayAlpha);

    p.noStroke();

    p.rect(0, 0, p.width, p.height);

​

    // Draw agents

    p.stroke(100, 255, 20, 60);

​

    for (var i = 0; i < agentCount; i++) {

      agents[i].update(strokeWidth);

    }

  }

​

};

​

var myp5 = new p5(sketch);

​

// -----2つの電荷を仮定する

//var plus = myp5.createVector(myp5.width*0.5, myp5.height/3);

//var minus = myp5.createVector(myp5.width*0.5, 400);

//var plus = myp5.createVector(300, 200);

//var minus = myp5.createVector(300, 400);

​

var Agent = function() {

  this.vector = myp5.createVector(myp5.random(myp5.width), myp5.random(myp5.height));

  this.vectorOld = this.vector.copy();

  this.stepSize = myp5.random(1, 5);

  this.isOutside = false;

  this.angle;

  this.ttl = 30 + Math.random()*100;

}

​

Agent.prototype.update = function(strokeWidth) {

  this.ttl--;

  let k_p = 30.0 /myp5.max(5, distance2( this.vector, plus));

  let k_m = -30.0 /myp5.max(5, distance2( this.vector, minus));

  this.vector.x += k_p * (this.vector.x - plus.x)

  this.vector.x += k_m * (this.vector.x - minus.x)

  this.vector.y += k_p * (this.vector.y - plus.y)

  this.vector.y += k_m * (this.vector.y - minus.y)

  this.isOutside = this.vector.x < 0 || this.vector.x > myp5.width || this.vector.y < 0 || this.vector.y > myp5.height;

​

  if (this.isOutside || this.ttl <0) {

    let x = myp5.width * myp5.random(100) * 0.01;

    let y = myp5.height * myp5.random(100) * 0.01;

​

    this.ttl = 50 + Math.random()*30;

    this.vector.set(x, y);

    this.vectorOld = this.vector.copy();

  }

​

  myp5.strokeWeight(strokeWidth);

​

  myp5.line(this.vectorOld.x, this.vectorOld.y, this.vector.x, this.vector.y);

  this.vectorOld = this.vector.copy();

  this.isOutside = false;

}

​

function distance2(v1, v2){

  return (v2.x-v1.x) * (v2.x-v1.x) + (v2.y-v1.y) * (v2.y-v1.y);

}

​