sihand – Project Week 11 – Free Turtle

sketch-sihan

//Sihan Dong
//sihand@andrew.cmu.edu
//Section B
//Week 11: Project turtle

var gravity = 0.3;   // downward acceleration
var springy = 0.7; // how much velocity is retained after bounce
var drag = 0.0001;    // drag causes particles to slow down
var np = 50;      // how many particles
var turtleColor = [];

function particleStep() {
    this.age++;
    this.x += this.dx;
    this.y += this.dy;
    stroke(this.dr, this.dg, this.db);
    strokeWeight(this.dw);
  
    if (this.x > width) { // bounce off right wall
        this.x = width - (this.x - width);
        this.dx = -this.dx * springy;
    } else if (this.x < 0) { // bounce off left wall
        this.x = -this.x;
        this.dx = -this.dx * springy;
    }
    if (this.y > height) { // bounce off bottom
        this.y = height - (this.y - height);
        this.dy = -this.dy * springy;
    } else if (this.y < 80) { // bounce off top
        this.y = 80 - (this.y - 80);//-this.y;
        this.dy = -this.dy * springy;
    }
    this.dy = this.dy + gravity; // force of gravity
    // drag is proportional to velocity squared
    // which is the sum of the squares of dy and dy
    var vs = Math.pow(this.dx, 2) + Math.pow(this.dy, 2);
    // d is the ratio of old velocty to new velocity
    var d = vs * drag;
    // d goes up with velocity squared but can never be
    // so high that the velocity reverses, so limit d to 1
    d = min(d, 1);
    // scale dx and dy to include drag effect
    this.dx *= (1 - d);
    this.dy *= (1 - d);

}

function particleDraw() {
    point(this.x, this.y);
}


// create a "Particle" object with position and velocity
function makeParticle(px, py, pdx, pdy, pr, pg, pb, pw) {
    p = {x: px, y: py,
         dx: pdx, dy: pdy, 
         dr: pr, dg: pg, db: pb,
         dw: pw,
         age: 0,
         step: particleStep,
         draw: particleDraw
        }
    return p;
}

var particles = [];


function setup() {
    createCanvas(500, 500);
    frameRate(8);
    turtleSlope = new makeTurtle(0, 0);

}


function draw() {
  background(184, 197, 245);

  //draw the chains
	for (i = 0; i < 25; i++) {
    turtleSlope.penUp();
    turtleSlope.right(30);
    turtleSlope.setColor(255);
    tSlope(20*i, 70); //1
    turtleSlope.setColor(0);
    tSlope(width/2, height/2-20); //2
    turtleColor[i] = color(random(100, 255), random(100, 255), random(100, 255));
    turtleSlope.setColor(turtleColor[i]);
    tSlope(100*i, 370); //3
    fill(0); 
	}

    if (mouseIsPressed) {
        var newp = makeParticle(mouseX, mouseY,
                                random(-10, 10), random(-10, 0), 
                                255, 255, 255,
                                random(10, 30));
        particles.push(newp);
    }

    newParticles = [];
    for (var i = 0; i < particles.length; i++) { // for each particle
        var p = particles[i];
        p.step();
        p.draw();
        if (p.age < 200) {
            newParticles.push(p);
        }
    }
    
    particles = newParticles;

}

function tSlope(lx, ly){
	turtleSlope.goto(lx, ly);
  turtleSlope.setWeight(4);
  turtleSlope.right(90);
  turtleSlope.forward(random(7));//the amount of fluctuation
  
  turtleSlope.penDown();
  turtleSlope.left(60);
  turtleSlope.forward(10);
  turtleSlope.right(60);
  turtleSlope.forward(10);
  turtleSlope.right(30);
  turtleSlope.forward(17.3);
  turtleSlope.right(120);
  turtleSlope.forward(17.3);
  turtleSlope.right(30);
  turtleSlope.forward(10);
  turtleSlope.right(60);
  turtleSlope.forward(10);
  turtleSlope.right(30);
	turtleSlope.penUp();

}

//========== TURTLE GRAPHICS ===============//
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 turtleSetColor(c) {
    this.color = c;
}
 
function turtleSetWeight(w) {
    this.weight = w;
}
 
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, 
                  setColor: turtleSetColor, setWeight: turtleSetWeight,
                  };
    return turtle;
}

I’ve wanted to experiment with how turtle moves so I did so with this project. The turnout is not exactly ideal and I will continue practicing with turtles.

I also experimented with the particles because I think their movements are fascinating.