Tiny Turtle is a fun Computer Science activity created by a ScriptEd volunteer that teaches students how to use JavaScript functions. The original documentation can be found here.
#Directions for Set Up
Step 1: New Repo
Create a new GitHub repo called TinyTurtle.
**Step 2: Clone** Clone your new repo into a Cloud 9 workspace with a similar name.
**Step 3: New Files** Create four new files in this workspace. Name these new files...
- index.html
- style.css
- script.js
- tinyTurtle.js
**Step 4: index.html** Copy and paste the code below into your index.html file
<!DOCTYPE html>
<html>
<head>
<title>Tiny Turtle</title>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
<h1>Tiny Turtle</h1>
<canvas></canvas>
<script src="tinyTurtle.js"></script>
<script src="script.js"></script>
</body>
</html>
Step 5: tinyTurtle.js
Copy and paste the code below into your tinyTurtle.js file
// tinyTurtle.js
// 2013-10-11
// Public Domain.
// For more information, see http://github.com/toolness/tiny-turtle.
function TinyTurtle(canvas) {
canvas = canvas || document.querySelector('canvas');
var self = this;
var rotation = 90;
var position = {
// See http://diveintohtml5.info/canvas.html#pixel-madness for
// details on why we're offsetting by 0.5.
x: canvas.width / 2 + 0.5,
y: canvas.height / 2 + 0.5
};
var isPenDown = true;
var radians = function(r) {return 2 * Math.PI * (r / 360) };
var triangle = function(ctx, base, height) {
ctx.beginPath(); ctx.moveTo(0, -base / 2); ctx.lineTo(height, 0);
ctx.lineTo(0, base / 2); ctx.closePath();
};
var rotate = function(deg) {
rotation = (rotation + deg) % 360;
if (rotation < 0) rotation += 360;
};
self.penStyle = 'black';
self.penWidth = 1;
self.penUp = function() { isPenDown = false; return self; };
self.penDown = function() { isPenDown = true; return self; };
self.forward = self.fd = function(distance) {
var origX = position.x, origY = position.y;
position.x += Math.cos(radians(rotation)) * distance;
position.y -= Math.sin(radians(rotation)) * distance;
if (!isPenDown) return;
var ctx = canvas.getContext('2d');
ctx.strokeStyle = self.penStyle;
ctx.lineWidth = self.penWidth;
ctx.beginPath();
ctx.moveTo(origX, origY);
ctx.lineTo(position.x, position.y);
ctx.stroke();
return self;
};
self.stamp = function(size) {
var ctx = canvas.getContext('2d');
ctx.save();
ctx.strokeStyle = ctx.fillStyle = self.penStyle;
ctx.lineWidth = self.penWidth;
ctx.translate(position.x, position.y);
ctx.rotate(-radians(rotation));
triangle(ctx, size || 10, (size || 10) * 1.5);
isPenDown ? ctx.fill() : ctx.stroke();
ctx.restore();
return self;
};
self.left = self.lt = function(deg) { rotate(deg); return self; };
self.right = self.rt = function(deg) { rotate(-deg); return self; };
Object.defineProperties(self, {
canvas: {get: function() { return canvas; }},
rotation: {get: function() { return rotation; }},
position: {get: function() { return {x: position.x, y: position.y}; }},
pen: {get: function() { return isPenDown ? 'down' : 'up'; }}
});
return self;
}
Step 6: Canvas CSS
You will notice a new HTML tag is being used. This tag is called canvas
In the style.css page give your canvas tag the following attributes
- a width of 400px
- a height of 400px
- a border (any style)
**Step 7: JavaScript Set Up** In the `script.js` page paste the code below on line 1
TinyTurtle.apply(window);
Step 8: Play Turtle
Tiny Turtle understands the following commands:
- forward();
- right();
- left();
- stamp(); <------ This shows which direction the turtle is pointing.
Use the commands above to make Tiny Turtle travel in a Square.
Step 9: House
For the final piece of this project create a house (square with a triangle ontop)