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gonzamoiguer/reaction-diffusion.js

Created November 22, 2018 04:16
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  1. gonzamoiguer created this gist Nov 22, 2018.
    135 changes: 135 additions & 0 deletions reaction-diffusion.js
    View file
    Original file line number Diff line number Diff line change
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    // Based on Shiffman's Reaction Diffusion Tut: https://youtu.be/Cl_Gjj80gPE
    //
    // Changed to simulate once, on startup
    // Then draw the lines of the resulting chains
    // Will need to update vector to Victor.js in order to use with plotter

    var tree = [];
    var walkers = [];
    var maxWalkers = 40;
    var iterations = 1000;
    var radius = 8;
    var hu = 0;
    var shrink = 0.995;
    var stuckCount = 0;
    var drawingComplete = false;

    function setup() {
    createCanvas(400, 400);

    tree[0] = new Walker(width / 2, height / 2);
    tree[0].isRoot = true;
    radius *= shrink;
    for (var i = 0; i < maxWalkers; i++) {
    walkers[i] = new Walker();
    radius *= shrink;
    }

    while(!drawingComplete){
    for (var n = 0; n < iterations; n++) {
    for (var i = walkers.length - 1; i >= 0; i--) {
    walkers[i].walk();
    if (walkers[i].checkStuck(tree)) {
    stuckCount++;
    if(stuckCount == 414){
    // por que 414 ??
    drawingComplete = true;
    }


    walkers[i].setHue(hu % 360);
    hu += 2;
    tree.push(walkers[i]);
    walkers.splice(i, 1);
    }
    }
    }

    //var r = walkers[walkers.length - 1].r;
    while (walkers.length < maxWalkers && radius > 1) {
    radius *= shrink;
    walkers.push(new Walker());
    }
    } // while !drawingComplete

    noFill();
    stroke(0);
    for(let i=0; i < tree.length; i++){
    DrawBranch(tree[i]);
    }


    }


    function DrawBranch(seed){
    if(!seed.linkedTo) return;
    line(seed.pos.x, seed.pos.y, seed.linkedTo.pos.x, seed.linkedTo.pos.y);
    DrawBranch(seed.linkedTo);
    }

    // Walker Object
    function Walker(x, y) {
    this.isRoot = false;
    this.linkedTo = false;
    if (arguments.length == 2) {
    this.pos = createVector(x, y);
    this.stuck = true;
    } else {
    this.pos = randomPoint();
    this.stuck = false;
    }
    this.r = radius;


    this.walk = function() {
    var vel = p5.Vector.random2D();
    // var vel = createVector(random(-1, 1), random(-0.5, 1));
    this.pos.add(vel);
    this.pos.x = constrain(this.pos.x, 0, width);
    this.pos.y = constrain(this.pos.y, 0, height);
    }


    this.checkStuck = function(others) {
    for (var i = 0; i < others.length; i++) {
    var d = distSq(this.pos, others[i].pos);
    if (d < (this.r * this.r + others[i].r * others[i].r + 2 * others[i].r * this.r)) {
    //if (random(1) < 0.1) {
    this.linkedTo = others[i];
    this.stuck = true;
    return true;
    break;
    //}
    }
    }
    return false;
    }


    }

    function randomPoint() {
    var i = floor(random(4));

    if (i === 0) {
    var x = random(width);
    return createVector(x, 0);
    } else if (i === 1) {
    var x = random(width);
    return createVector(x, height);
    } else if (i === 2) {
    var y = random(height);
    return createVector(0, y);
    } else {
    var y = random(height);
    return createVector(width, y);
    }
    }


    function distSq(a, b) {
    var dx = b.x - a.x;
    var dy = b.y - a.y;
    return dx * dx + dy * dy;
    }