Blinking Eyes

  		/**
			 * Copyright (C) 2011 Hakim El Hattab, http://hakim.se
			 * 
			 * Permission is hereby granted, free of charge, to any person obtaining a copy
			 * of this software and associated documentation files (the "Software"), to deal
			 * in the Software without restriction, including without limitation the rights
			 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
			 * copies of the Software, and to permit persons to whom the Software is
			 * furnished to do so, subject to the following conditions:
			 * 
			 * The above copyright notice and this permission notice shall be included in
			 * all copies or substantial portions of the Software.
			 * 
			 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
			 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
			 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
			 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
			 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
			 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
			 * THE SOFTWARE.
			 * 
			 * @author Hakim El Hattab | http://hakim.se
			 */
			(function(){
				
				var DISPLAY_WIDTH = 960,
					DISPLAY_HEIGHT = 480,
					DISPLAY_DURATION = 10,
					OVERLAY_DURATION = 3;
				
				var	mouse = { x: 0, y: 0 },
					container,
					overlay,
					overlayOpacity = 1,
					canvas,
					context,
					startTime,
					eyes;
				
				function initialize() {
					container = document.getElementById( 'fof' );
					overlay = document.querySelector( '#fof>div' );
					canvas = document.querySelector( '#fof>canvas' );
					
					if( canvas ) {
						canvas.width = DISPLAY_WIDTH;
						canvas.height = DISPLAY_HEIGHT;
						
						context = canvas.getContext( '2d' );
						
						document.addEventListener( 'mousemove', function( event ) {
							mouse.x = event.clientX;
							mouse.y = event.clientY;
						}, false );
						
						eyes = [
							new Eye( canvas,   0.50, 0.50,   5.00,    0.10 ),
							
							new Eye( canvas,   0.19, 0.80,   0.88,    0.31 ), 
							new Eye( canvas,   0.10, 0.54,   0.84,    0.32 ), 
							new Eye( canvas,   0.81, 0.13,   0.63,    0.33 ), 
							new Eye( canvas,   0.89, 0.19,   0.58,    0.34 ), 
							new Eye( canvas,   0.40, 0.08,   0.97,    0.35 ), 
							new Eye( canvas,   0.64, 0.74,   0.57,    0.36 ), 
							new Eye( canvas,   0.41, 0.89,   0.56,    0.37 ), 
							new Eye( canvas,   0.92, 0.89,   0.75,    0.38 ), 
							new Eye( canvas,   0.27, 0.20,   0.87,    0.39 ), 
							new Eye( canvas,   0.17, 0.46,   0.68,    0.41 ), 
							new Eye( canvas,   0.71, 0.29,   0.93,    0.42 ), 
							new Eye( canvas,   0.84, 0.46,   0.54,    0.43 ), 
							new Eye( canvas,   0.93, 0.35,   0.63,    0.44 ), 
							new Eye( canvas,   0.77, 0.82,   0.85,    0.45 ), 
							new Eye( canvas,   0.36, 0.74,   0.90,    0.46 ), 
							new Eye( canvas,   0.13, 0.24,   0.85,    0.47 ), 
							new Eye( canvas,   0.58, 0.20,   0.77,    0.48 ), 
							new Eye( canvas,   0.55, 0.84,   0.87,    0.50 ), 
						];
						
						startTime = Date.now();
						
						animate();
					}
					else if( overlay ) {
						overlay.parentElement.removeChild( overlay );
					}
				}
				
				function animate() {
					// The number of seconds that have passed since initialization
					var seconds = ( Date.now() - startTime ) / 1000;
					
					// Out with the old ...
					context.clearRect( 0, 0, DISPLAY_WIDTH, DISPLAY_HEIGHT );
					
					// ... in with the new
					for( var i = 0, len = eyes.length; i < len; i++ ) {
						var eye = eyes[i];
						
						if( seconds > eye.activationTime * DISPLAY_DURATION ) {
							eye.activate();
						};
						
						eye.update( mouse );
					}
					
					// Remove the overlay if its time has passed
					if( seconds > OVERLAY_DURATION && overlay !== undefined ) {
						
						// Ease-in
						overlayOpacity *= 0.94 + ( 0.055 * overlayOpacity );
						overlayOpacity = Math.max( overlayOpacity - 0.01, 0 );
						
						overlay.style.opacity = overlayOpacity;
						
						if( overlayOpacity === 0 ) {
							// We have no more use for the overlay, removing it ensures
							// that we do not repeatedly enter this if statement
							container.removeChild( overlay );
							
							overlay = undefined;
						}
					}
					
					requestAnimFrame( animate );
				}
				
				window.addEventListener ? window.addEventListener( 'load', initialize, false ) : window.onload = initialize;
				
			})();


			function Eye( canvas, x, y, scale, time ) {
				this.canvas = canvas;
				this.context = this.canvas.getContext( '2d' )
				
				// The time at which this eye will come alive
				this.activationTime = time;
				
				// The speed at which the iris follows the mouse
				this.irisSpeed = 0.01 + ( Math.random() * 0.2 ) / scale;
				
				// The speed at which the eye opens and closes
				this.blinkSpeed = 0.2 + ( Math.random() * 0.2 );
				this.blinkInterval = 5000 + 5000 * ( Math.random() );
				
				// Timestamp of the last blink
				this.blinkTime = Date.now();
				
				this.scale = scale;
				this.size = 70 * scale;
				
				this.x = x * canvas.width; 
				this.y = y * canvas.height + ( this.size * 0.15 );
				
				this.iris = {
					x: this.x,
					y: this.y - ( this.size * 0.1 ),
					size: this.size * 0.2
				};
				
				this.pupil = {
					width: 2 * scale,
					height: this.iris.size * 0.75
				};
				
				this.exposure = {
					top: 0.1 + ( Math.random() * 0.3 ),
					bottom: 0.5 + ( Math.random() * 0.3 ),
					current: 0,
					target: 1
				};
				
				// Affects the amount of inner shadow
				this.tiredness = ( 0.5 - this.exposure.top ) + 0.1;
				
				this.isActive = false;
				
				this.activate = function() {
					this.isActive = true;
				}
				
				this.update = function( mouse ) {
					if( this.isActive === true ) {
						this.render( mouse );
					}
				}
				
				this.render = function( mouse ) {
					var time = Date.now();
					
					if( this.exposure.current < 0.012 ) {
						this.exposure.target = 1;
					}
					else if( time - this.blinkTime > this.blinkInterval ) {
						this.exposure.target = 0;
						this.blinkTime = time;
					}
					
					this.exposure.current += ( this.exposure.target - this.exposure.current ) * this.blinkSpeed;
					
					// Eye left/right
					var el = { x: this.x - ( this.size * 0.8 ), y: this.y - ( this.size * 0.1 ) };
					var er = { x: this.x + ( this.size * 0.8 ), y: this.y - ( this.size * 0.1 ) };
					
					// Eye top/bottom
					var et = { x: this.x, y: this.y - ( this.size * ( 0.5 + ( this.exposure.top * this.exposure.current ) ) ) };
					var eb = { x: this.x, y: this.y - ( this.size * ( 0.5 - ( this.exposure.bottom * this.exposure.current ) ) ) };
					
					// Eye inner shadow top
					var eit = { x: this.x, y: this.y - ( this.size * ( 0.5 + ( ( 0.5 - this.tiredness ) * this.exposure.current ) ) ) };
					
					// Eye iris
					var ei = { x: this.x, y: this.y - ( this.iris.size ) };
					
					// Offset the iris depending on mouse position
					var eio = { 
						x: ( mouse.x - ei.x ) / ( window.innerWidth - ei.x ), 
						y: ( mouse.y ) / ( window.innerHeight )
					};
					
					// Apply the iris offset
					ei.x += eio.x * 16 * Math.max( 1, this.scale * 0.4 );
					ei.y += eio.y * 10 * Math.max( 1, this.scale * 0.4 );
					
					this.iris.x += ( ei.x - this.iris.x ) * this.irisSpeed;
					this.iris.y += ( ei.y - this.iris.y ) * this.irisSpeed;
					
					// Eye fill drawing
					this.context.fillStyle = 'rgba(255,255,255,1.0)';
					this.context.strokeStyle = 'rgba(100,100,100,1.0)';
					this.context.beginPath();
					this.context.lineWidth = 3;
					this.context.lineJoin = 'round';
					this.context.moveTo( el.x, el.y );
					this.context.quadraticCurveTo( et.x, et.y, er.x, er.y );
					this.context.quadraticCurveTo( eb.x, eb.y, el.x, el.y );
					this.context.closePath();
					this.context.stroke();
					this.context.fill();
					
					// Iris
					this.context.save();
					this.context.globalCompositeOperation = 'source-atop';
					this.context.translate(this.iris.x*0.1,0);
					this.context.scale(0.9,1);
					this.context.strokeStyle = 'rgba(0,0,0,0.5)';
					this.context.fillStyle = 'rgba(130,50,90,0.9)';
					this.context.lineWidth = 2;
					this.context.beginPath();
					this.context.arc(this.iris.x, this.iris.y, this.iris.size, 0, Math.PI*2, true);
					this.context.fill();
					this.context.stroke();
					this.context.restore();
					
					// Iris inner
					this.context.save();
					this.context.shadowColor = 'rgba(255,255,255,0.5)';
					this.context.shadowOffsetX = 0;
					this.context.shadowOffsetY = 0;
					this.context.shadowBlur = 2 * this.scale;
					this.context.globalCompositeOperation = 'source-atop';
					this.context.translate(this.iris.x*0.1,0);
					this.context.scale(0.9,1);
					this.context.fillStyle = 'rgba(255,255,255,0.2)';
					this.context.beginPath();
					this.context.arc(this.iris.x, this.iris.y, this.iris.size * 0.7, 0, Math.PI*2, true);
					this.context.fill();
					this.context.restore();
					
					// Pupil
					this.context.save();
					this.context.globalCompositeOperation = 'source-atop';
					this.context.fillStyle = 'rgba(0,0,0,0.9)';
					this.context.beginPath();
					this.context.moveTo( this.iris.x, this.iris.y - ( this.pupil.height * 0.5 ) );
					this.context.quadraticCurveTo( this.iris.x + ( this.pupil.width * 0.5 ), this.iris.y, this.iris.x, this.iris.y + ( this.pupil.height * 0.5 ) );
					this.context.quadraticCurveTo( this.iris.x - ( this.pupil.width * 0.5 ), this.iris.y, this.iris.x, this.iris.y - ( this.pupil.height * 0.5 ) );
					this.context.fill();
					this.context.restore();
					
					this.context.save();
					this.context.shadowColor = 'rgba(0,0,0,0.9)';
					this.context.shadowOffsetX = 0;
					this.context.shadowOffsetY = 0;
					this.context.shadowBlur = 10;
					
					// Eye top inner shadow
					this.context.fillStyle = 'rgba(120,120,120,0.2)';
					this.context.beginPath();
					this.context.moveTo( el.x, el.y );
					this.context.quadraticCurveTo( et.x, et.y, er.x, er.y );
					this.context.quadraticCurveTo( eit.x, eit.y, el.x, el.y );
					this.context.closePath();
					this.context.fill();
					
					this.context.restore();
					
				}
			}

			// shim with setTimeout fallback from http://paulirish.com/2011/requestanimationframe-for-smart-animating/
			window.requestAnimFrame = (function(){
			  return  window.requestAnimationFrame       || 
			          window.webkitRequestAnimationFrame || 
			          window.mozRequestAnimationFrame    || 
			          window.oRequestAnimationFrame      || 
			          window.msRequestAnimationFrame     || 
			          function(/* function */ callback, /* DOMElement */ element){
			            window.setTimeout(callback, 1000 / 60);
			          };
			})();