sntong-Project 11: Freestyle: Playing with your Turtle(s)

sketch

// Scarlet Tong
// sntong@andrew.cmu.edu
// Section A
// Project 11: Freestyle: Playing with your Turtle(s)

// intialize global Turtle
var nTurtle;

function setup(){
  createCanvas(400,400);
  background(0);
  frameRate(60);
}


function draw(){
  // draw a new pattern when mouse is pressed located at mouseX and mouseY
if (mouseIsPressed) {

  nTurtle = new makeTurtle(mouseX,mouseY);
  // offset of lines from the center according the location of mouseX on the canvas
  var step = map(mouseX,0,width,2,40);
  // rotation of the lines stop and start at a location that is determined by mouseY
  var ratio = map(mouseY,0,height,100,150);
  // Each pattern as a maxium of 20 lines
  for (var i = 0; i < 20; i++) {
    nTurtle.setColor(color(random(255),random(100,255),random(100,255)));
    // lines function found below draw function
    lines();
    // start drawing shapes
    nTurtle.penUp();
    // offset the next lines step pixels away from the previous one
    nTurtle.forward(step);
    // rotate that new line with a set angle
    nTurtle.right(ratio);
    // end the shape
    nTurtle.penDown();
    }
  }

}


// draw lines
function lines(){
    nTurtle.setWeight(1);
    nTurtle.penDown();
    nTurtle.forward(5);
    nTurtle.penUp();
}


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 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};
return turtle;}

For this project I wanted to create a changing pattern that will track the mouse when it is pressed down. The pattern is drawn by the turtle graphics and has varying color.