brandenhall/Sample Usage

## knock.js
//-----------------------------------------------------------------------------
// Secret Knock Detector
// Based on http://grathio.com/2009/11/secret_knock_detecting_door_lock/
//-----------------------------------------------------------------------------
// Created by Branden Hall, bhall at automatastudios dot com
//-----------------------------------------------------------------------------
// Copyright (c) Automata Studios Ltd.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:

// Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer. Redistributions in binary
// form must reproduce the above copyright notice, this list of conditions and
// the following disclaimer in the documentation and/or other materials
// provided with the distribution. Neither the name of Automata Studios nor
// the names of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//-----------------------------------------------------------------------------

define(function(require) {

	var successCallback;
	var secretKnock;
	var knockInput = [];
	var reject = 0.25;
	var averageReject = 0.15;
	var fadeTime = 150;
	var completeTime = 1200;
	var completeId;
	var lastNow;
	var getEventX;
	var getEventY;

	function enableKnock(callback, knock) {
		successCallback = callback;
		secretKnock = knock;

		if ('ontouchstart' in document.documentElement) {
			document.addEventListener("touchstart", detectKnock);
			getEventX = function(e) {
				return event.touches[0].pageX;
			}
			getEventY = function(e) {
				return event.touches[0].pageY;
			}

		} else {
			document.addEventListener("click", detectKnock);
			getEventX = function(e) {
				return event.pageX;
			}
			getEventY = function(e) {
				return event.pageY;
			}
		}
	}

	function disableKnock() {
		document.removeEventListener("touchstart", detectKnock);
		document.removeEventListener("click", detectKnock);
		clearInterval(completeId);
	}

	function detectKnock(e) {
		var now = new Date().getTime();


		knockInput.push({time:(new Date()).getTime(),
						 x:getEventX(e),
						 y:getEventY(e)});

		clearTimeout(completeId);
		completeId = setTimeout(completeKnock, 1200);

		e.preventDefault();
		return false;
	}

	function completeKnock() {
		if (validateKnock()) {
			successCallback();
		}

		knockInput = [];
	}

	function validateKnock() {
		var maxTime = 0;
		var times = [];
		var time;
		var result = true;
		var dist, i;
		var timeDiff, totalDiff;

		// make sure they're the same length
		if (secretKnock.length == knockInput.length) {

			// first check the position of the knocks and gather the times
			for (i=0; i<knockInput.length && result; ++i) {
				dist = Math.sqrt(Math.pow(knockInput[i].x - secretKnock[i].x, 2) +
							     Math.pow(knockInput[i].y - secretKnock[i].y, 2));

				if (dist < secretKnock[i].radius) {

					if (i > 0) {
						time = knockInput[i].time - knockInput[i - 1].time;
						times.push(time);
						maxTime = Math.max(maxTime, time);
					}

				} else {
					result = false;
				}
			}

			for (i=0; i<times.length && result; ++i) {
				timeDiff = Math.abs((times[i] / maxTime) - secretKnock[i].delay);
				totalDiff += timeDiff;

				if (timeDiff > reject) {
					result = false;
				}
			}

			if (result && totalDiff/times.length > averageReject) {
				result = false;
			}

		} else {
			result = false;
		}

		return result;
	}

	var pub = {};
	pub.enableKnock = enableKnock;
	pub.disableKnock = disableKnock;

	return pub;
});

## Sample Usage
// Shave-and-a-haircut, two bits! In the upper left corner
var secret = [{delay:0.5,  x:0,    y:0, radius:200},
			  {delay:0.25, x:0,    y:0, radius:200},
			  {delay:0.25, x:0,    y:0, radius:200},
			  {delay:0.5,  x:0,    y:0, radius:200},
			  {delay:1,    x:0,    y:0, radius:200},
			  {delay:0.5,  x:0,    y:0, radius:200},
			  {delay:0,    x:0,    y:0, radius:200}];

function allowInside() {
	alert("Good job!");
}

knock.enableKnock(allowInside, secret);
	//-----------------------------------------------------------------------------
	// Secret Knock Detector
	// Based on http://grathio.com/2009/11/secret_knock_detecting_door_lock/
	//-----------------------------------------------------------------------------
	// Created by Branden Hall, bhall at automatastudios dot com
	//-----------------------------------------------------------------------------
	// Copyright (c) Automata Studios Ltd.
	// All rights reserved.
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions
	// are met:

	// Redistributions of source code must retain the above copyright notice, this
	// list of conditions and the following disclaimer. Redistributions in binary
	// form must reproduce the above copyright notice, this list of conditions and
	// the following disclaimer in the documentation and/or other materials
	// provided with the distribution. Neither the name of Automata Studios nor
	// the names of its contributors may be used to endorse or promote products
	// derived from this software without specific prior written permission.
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
	// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	// POSSIBILITY OF SUCH DAMAGE.
	//-----------------------------------------------------------------------------

	define(function(require) {

	var successCallback;
	var secretKnock;
	var knockInput = [];
	var reject = 0.25;
	var averageReject = 0.15;
	var fadeTime = 150;
	var completeTime = 1200;
	var completeId;
	var lastNow;
	var getEventX;
	var getEventY;

	function enableKnock(callback, knock) {
	successCallback = callback;
	secretKnock = knock;

	if ('ontouchstart' in document.documentElement) {
	document.addEventListener("touchstart", detectKnock);
	getEventX = function(e) {
	return event.touches[0].pageX;
	}
	getEventY = function(e) {
	return event.touches[0].pageY;
	}

	} else {
	document.addEventListener("click", detectKnock);
	getEventX = function(e) {
	return event.pageX;
	}
	getEventY = function(e) {
	return event.pageY;
	}
	}
	}

	function disableKnock() {
	document.removeEventListener("touchstart", detectKnock);
	document.removeEventListener("click", detectKnock);
	clearInterval(completeId);
	}

	function detectKnock(e) {
	var now = new Date().getTime();



	knockInput.push({time:(new Date()).getTime(),
	x:getEventX(e),
	y:getEventY(e)});

	clearTimeout(completeId);
	completeId = setTimeout(completeKnock, 1200);

	e.preventDefault();
	return false;
	}

	function completeKnock() {
	if (validateKnock()) {
	successCallback();
	}

	knockInput = [];
	}

	function validateKnock() {
	var maxTime = 0;
	var times = [];
	var time;
	var result = true;
	var dist, i;
	var timeDiff, totalDiff;

	// make sure they're the same length
	if (secretKnock.length == knockInput.length) {

	// first check the position of the knocks and gather the times
	for (i=0; i<knockInput.length && result; ++i) {
	dist = Math.sqrt(Math.pow(knockInput[i].x - secretKnock[i].x, 2) +
	Math.pow(knockInput[i].y - secretKnock[i].y, 2));

	if (dist < secretKnock[i].radius) {

	if (i > 0) {
	time = knockInput[i].time - knockInput[i - 1].time;
	times.push(time);
	maxTime = Math.max(maxTime, time);
	}

	} else {
	result = false;
	}
	}

	for (i=0; i<times.length && result; ++i) {
	timeDiff = Math.abs((times[i] / maxTime) - secretKnock[i].delay);
	totalDiff += timeDiff;

	if (timeDiff > reject) {
	result = false;
	}
	}

	if (result && totalDiff/times.length > averageReject) {
	result = false;
	}

	} else {
	result = false;
	}

	return result;
	}

	var pub = {};
	pub.enableKnock = enableKnock;
	pub.disableKnock = disableKnock;

	return pub;
	});
	// Shave-and-a-haircut, two bits! In the upper left corner
	var secret = [{delay:0.5, x:0, y:0, radius:200},
	{delay:0.25, x:0, y:0, radius:200},
	{delay:0.25, x:0, y:0, radius:200},
	{delay:0.5, x:0, y:0, radius:200},
	{delay:1, x:0, y:0, radius:200},
	{delay:0.5, x:0, y:0, radius:200},
	{delay:0, x:0, y:0, radius:200}];

	function allowInside() {
	alert("Good job!");
	}

	knock.enableKnock(allowInside, secret);