// X is ignored in drawing

​

let axiom = "X";

let delta = 25;

let rules = []; // put rules in an array so you can loop over them

rules[0] = {

  a: "X",

  b: "FX[--FX][FX][++FX]"

}

​

rules[1] = {

  a: "F",

  b:"FF"  

​

}

​

​

//console.log(rules);

let mysentence = axiom;

let mybutton;

let len;

let myinput;

let myrule;

let sentenceOut;

​

function setup() {

  createCanvas(windowWidth/2, windowHeight/1.5);

  background(0);

  angleMode(DEGREES);

  stroke(0, 255, 0,100);

  strokeWeight(2);

  //noCanvas();

  myinput = createInput("3");

  myrule = createInput("FX[--FX][FX][++FX]");

  mybutton = createButton("generate");

  mybutton.mousePressed(instructPrint);

  createP("The axiom is 'X'");

  createP("You can control the number of generations of the rule 1-7");

  createP("You are controling one rule  X => FX[--FX][FX][++FX]");

  createP("push '[', pop ']' and forward 'F', 'X' is not printed it just controls the curve");

  createP("the second rule F => FF, makes the tree have a longer trunk");

  createP("copy and paste this nice rule F+[[X]-X]-F[-FX]+X or refresh if you get stuck!");

  createP("******instructions for plant******");

  //translate(width/2,height);

  sentenceOut = createP(axiom);

  instructPrint();

}

​

function instructPrint(){

  //callback function for mousepressed button

  // constrain the values so it will not kill the browser

  rules[0].b = myrule.value();

  let genera = constrain(int(myinput.value()),1,7);

  //len = 8 -genera;  

  //len = 20

  len = map(genera,1,7,10,1);  // map the length to generations

  //console.log("length",len);

  let myinstructions = instruct(mysentence, genera);

 // console.log(mysentence,int(myinput.value()));

  turtle(myinstructions)

}

​

​

​

function instruct(sentence,number){

    let longSentence =""

    for(let i=0;i<number;i++){

        longSentence = generate(sentence)

        sentence = longSentence

    }

    return sentence

}

​

​

​

function generate(sentence) {

  //console.log("generate",sentence);

  //len *=0.618;

  let nextsentence = "";

  for (let i = 0; i < sentence.length; i++) {

    let current = sentence.charAt(i); // get char in sentence

    let found = false; // a catch to see if it is found

    for (let j = 0; j < rules.length; j++) { // loop over the rules array

      if (current == rules[j].a) {

        nextsentence += rules[j].b

        found = true;

        break; // only one rule can be true at a time;

      }

​

    }

    if (!found) {

      nextsentence += current

​

    }

  }

  sentence = nextsentence // 

  sentenceOut.html(sentence);

  return sentence

​

}

​

function turtle(sentence) {

  background(0);

  resetMatrix(); // need to reset the matrix each time through

  translate(width/2,height);  // turtle origin

  for (let i = 0; i < sentence.length; i++) {

    let current = sentence.charAt(i); // get char in sentence

    switch (current) {

      case "F":

        stroke(random(255),random(255), random(255));

        line(0, 0, 0, -len); // turtle starts by moving up from origin

        translate(0, -len); // trans to end of that line

        //console.log("boom")

        break;

      case "+":

        rotate(delta); //PI/6

        break;

      case "-":

        rotate(-delta); //PI/6

        break;

      case "[":

        push();

        break;

      case "]":

        pop(); 

        break;

​

    }

​

  }

​

​

}