function KeyboardInput() {
	var keys = [];
	var press = [];
	var release = [];

	this.attach = function() {
		for(var i = 0; i < 256; i++) {
			keys[i] = false;
			press[i] = false;
			release[i] = false;
		}

		window.addEventListener("keydown", function(event) {
			if(!keys[event.keyCode]) {
				press[event.keyCode] = true;
			}
			keys[event.keyCode] = true;
		});

		window.addEventListener("keyup", function(event) {
			if(keys[event.keyCode]) {
				release[event.keyCode] = true;
			}
			keys[event.keyCode] = false;
		});
	}

	this.isPressed = function(code) {
		var pressed = press[code] && keys[code];
		press[code] = false;
		return pressed;
	}

	this.isReleased = function(code) {
		var released = release[code] && !keys[code];
		release[code] = false;
		return released;
	}

	this.isDown = function(code) {
		return keys[code];
	}
};

window.Keys = {
	Left: 37,
	Up: 38,
	Right: 39,
	Down: 40,
	W: 87,
	A: 65,
	S: 83,
	D: 68,
	Space: 32
};