rsp1-Project-Compostion-Turtle-Freestyle

sketch

/*Rachel Park
rsp1@andrew.cmu.edu
Section B @ 10:30AM
Project 11: Turtle...anything*/

var myTurtle;//global variable for defining a new name for the turtle
function setup() {
  createCanvas(330,400);
  background(0);
  noLoop();
  myTurtle = new makeTurtle(width/2-50,20)//the turtle
}

function draw() {
  var dragon = dragonCurve(14);//variable to substitute in for function
  turtleDraw(dragon,200,90,2);//drawing the line
}

function dragonCurve(depth){//using L-system logic to create pattern
    if(depth === 0){
      return 'FX';}

    var turtle = dragonCurve(depth - 1);
    var newTurtle = '';
    for(var i = 0; i < turtle.length; i++){
        if(turtle.charAt(i) === 'X'){
            newTurtle += 'X+YF+';
        }
        else if (turtle.charAt(i) === 'Y'){
            newTurtle += '-FX-Y';
        }
        else {
            newTurtle += turtle.charAt(i);
        }
    }
    return newTurtle;
}


//------------------------------------------------
function turtleDraw(text, startx, starty, length) {//using turtle functions to draw out the patterns
    var direction = 0;
    var x = startx;//initial horizontal position of line
    var y = starty;//initial verticle position of line

    for(var i = 0; i < text.length; i++){

        if(text.charAt(i) === 'F'){
            //'F', draw forward length in direction
            var endx = x + length * Math.cos(direction * 0.017453292519);
            var endy = y + length * Math.sin(direction * 0.017453292519);

            var red = x/400 * 255;
            var green = y/400 * 255;
            var blue = (x + y + 300)/400 * 255;
            c = stroke(red,green,blue);
            myTurtle.setColor(c);//setting gradient color of lines

            line(x,y,endx,endy);//drawing the line
            x = endx;//reinitializing to new horizontal position
            y = endy;//reinitializing to new verticle position
        }
        else if(text.charAt(i) === '-'){
            //90 degrees added to direction
            direction += 90;
        }
        else if(text.charAt(i) === '+'){
            //90 degrees substracted from direction
            direction -= 90;
        }
    }
}
//-------------------------------------------------------
//other turtle functions

function turtleLeft(d){
  this.angle-=d;
}

function turtleRight(d){
  this.angle+=d;
}

function turtleForward(p){
  var rad=radians(this.angle);
  var newx=this.x+cos(rad)*p;
  var newy=this.y+sin(rad)*p;
  this.goto(newx,newy);
}

function turtleBack(p){
this.forward(-p);
}

function turtlePenDown(){
  this.penIsDown=true;
}

function turtlePenUp(){
  this.penIsDown = false;
}

function turtleGoTo(x,y){
  if(this.penIsDown){stroke(this.color);strokeWeight(this.weight);
    line(this.x,this.y,x,y);
  }
  this.x = x;
  this.y = y;
}

function turtleDistTo(x,y){
return sqrt(sq(this.x-x)+sq(this.y-y));
}

function turtleAngleTo(x,y){
  var absAngle=degrees(atan2(y-this.y,x-this.x));
  var angle=((absAngle-this.angle)+360)%360.0;return angle;
}

function turtleTurnToward(x,y,d){
  var angle = this.angleTo(x,y);
    if(angle< 180){
      this.angle+=d;
    } else{
      this.angle-=d;
      }
}

function turtleSetColor(c){
  this.color=c;
}

function turtleSetWeight(w){
  this.weight=w;
}

function turtleFace(angle){
this.angle = angle;
}

function turtleReset(){
  this.reset = 0;
}

function makeTurtle(tx,ty){
  var turtle={x:tx,y:ty,
    angle:0.0,penIsDown:true,color:color(128),weight:1,left:turtleLeft,
    right:turtleRight,forward:turtleForward, back:turtleBack,penDown:turtlePenDown,
    penUp:turtlePenUp,goto:turtleGoTo, angleto:turtleAngleTo,
    turnToward:turtleTurnToward,distanceTo:turtleDistTo, angleTo:turtleAngleTo,
    setColor:turtleSetColor, setWeight:turtleSetWeight,face:turtleFace,
    reset:turtleReset};

    return turtle;}

In searching for inspiration, I happened across the notion of the L-systems. I really liked how the visual of this specific patterned looked and wanted to try it out for myself. Although I did find resources to help me with the L-systems logic to generate the pattern because of its specific equations and such, I found that the over code was pretty straightforward in its use of the turtle graphics functions.