A CodePen by Noel Delgado. Direction-aware 3D hover effect - After seeing this site http://fitzfitzpatrick.com/ I decided to give a try to the "direction-aware hover effect". My first thought was to do it with a pure CSS, not too late I changed my mind and decided to use JS (I need to sleep anyway). It's kind of simple, using JS we can easily de…

index.haml

- @icons = ["happy", "wink", "devil", "wink2", "unhappy", "sleep", "thumbsup", "surprised", "displeased", "angry", "cry", "shoot"]

%header
  .container
    %h1 Direction-aware hover effect
    %p CSS & bits of JS
.container
  %ul
    - @icons.each do |face|
      %li
        %a{:href => "#", :class => "normal"}
          - # %span{:class => "fontelico-emo-#{face}"}
          %svg{:viewBox => "0 0 80 76", :x => "0px", :y => "0px"}
            %g
              %path{:d => "M 68.9708 24.8623 L 60.4554 2.3018 C 59.9641 0.7017 58.1628 -0.2583 56.5252 0.3817 L 1.9822 20.2222 C 0.3822 20.7022 -0.4179 22.6222 0.2222 24.2223 L 8.8624 47.7797 L 8.8624 35.1484 C 8.8624 29.5024 13.3425 24.8623 18.8857 24.8623 L 32.9442 24.8623 L 50.63 12.862 L 60.7829 24.8623 L 68.9708 24.8623 L 68.9708 24.8623 ZM 77.098 32.0625 L 18.8857 32.0625 C 17.2512 32.0625 16.0625 33.4511 16.0625 35.1484 L 16.0625 72.8491 C 16.0625 74.5477 17.2512 75.9375 18.8857 75.9375 L 77.098 75.9375 C 78.742 75.9375 79.9376 74.5477 79.9376 72.8491 L 79.9376 35.1484 C 79.9376 33.4511 78.742 32.0625 77.098 32.0625 L 77.098 32.0625 ZM 73.0626 68.0625 L 23.9375 68.0625 L 23.9375 61.0852 L 31.4704 43.7232 L 42.7696 57.6777 L 53.4138 46.8062 L 67.1695 41.9375 L 73.0626 55.0815 L 73.0626 68.0625 L 73.0626 68.0625 Z"}
        .info
          %h3 Single-origin coffee whatever
          %p Williamsburg tofu polaroid, 90's Bushwick irony locavore ethnic meh messenger bag Truffaut jean shorts.

script.js

// - Noel Delgado | @pixelia_me


var nodes  = document.querySelectorAll('li'),
    _nodes = [].slice.call(nodes, 0);

var getDirection = function (ev, obj) {
    var w = obj.offsetWidth,
        h = obj.offsetHeight,
        x = (ev.pageX - obj.offsetLeft - (w / 2) * (w > h ? (h / w) : 1)),
        y = (ev.pageY - obj.offsetTop - (h / 2) * (h > w ? (w / h) : 1)),
        d = Math.round( Math.atan2(y, x) / 1.57079633 + 5 ) % 4;
  
    return d;
};

var addClass = function ( ev, obj, state ) {
    var direction = getDirection( ev, obj ),
        class_suffix = "";
    
    obj.className = "";
    
    switch ( direction ) {
        case 0 : class_suffix = '-top';    break;
        case 1 : class_suffix = '-right';  break;
        case 2 : class_suffix = '-bottom'; break;
        case 3 : class_suffix = '-left';   break;
    }
    
    obj.classList.add( state + class_suffix );
};

// bind events
_nodes.forEach(function (el) {
    el.addEventListener('mouseover', function (ev) {
        addClass( ev, this, 'in' );
    }, false);

    el.addEventListener('mouseout', function (ev) {
        addClass( ev, this, 'out' );
    }, false);
});

style.scss

@import "compass";
/* fonts */
@import url(http://fonts.googleapis.com/css?family=Bree+Serif);
//@import url(http://weloveiconfonts.com/api/?family=fontelico);

/* vars */
$w: 200;
$h: 180;
$duration: 300ms;
$timing-fn: ease;
/* colors */
$turquoise: #1ABC9C;
$wet-asphalt: #34495E;
$midnight-blue: #2C3E50;
$clouds: #ECF0F1;

* {@include box-sizing(border-box)}
body {background-color: #fff}

// [class*="fontelico-"]:before {font-family: 'fontelico', sans-serif}

h1 {margin: 0 auto 5px; text-align: center}
h3 {font-family: 'Bree Serif', serif}
.container {width: 840px; margin: 0 auto}
header {
  font-family: 'Bree Serif', serif;
  text-align: center; margin: 50px 0 25px;
  color: $wet-asphalt;
  p {
    margin: 0;
    color: transparentize($wet-asphalt, .6);
  }
}

ul {padding: 0; margin: 0 0 50px;
  &:after {content: "."; display: block; clear: both; visibility: hidden; line-height: 0; height: 0}
}

li {
  position: relative;
  overflow: hidden;
  border-radius: 4px;
  list-style: none;
  float: left;
  width: #{$w}px;
  height: #{$h}px;
  margin: 5px;
  padding: 0;
  perspective: 500px;
  a  {
    display: inline-block;
    vertical-align: top;
    text-decoration: none;
    border-radius: 4px;
  }
  h3 {
    margin: 0; font-size: 16px; color: transparentize(#fff, .1);
  }
  p  {
    font-size: 12px; line-height: 1.5; color: transparentize(#fff, .2);
  }
  .normal {
    width: 100%;
    height: 100%;
    background-color: $clouds;
    color: transparentize($wet-asphalt, .4);
    box-shadow: inset 0 2px 20px darken($clouds, 2);
    text-align: center;
    font-size: 50px;
    line-height: #{$h}px;
    // span {pointer-events: none;}
    svg {
      pointer-events: none;
      width: 50px;
      path {
        fill: transparentize($wet-asphalt, .8);
      }
    }
  }
  .info {
    width: 100%;
    height: 100%;
    padding: 20px;
    position: absolute;
    top: 0;
    left: 0;
    overflow: hidden;
    border-radius: 4px;
    pointer-events: none;
    background-color: transparentize($turquoise, .1);
    transform: rotate3d(1, 0, 0, 90deg);
  }
}

.in-top .info {
   transform-origin: 50% 0%;
   animation: in-top $duration $timing-fn 0ms 1 forwards;
}
.in-right .info {
  transform-origin: 100% 0%;
  animation: in-right $duration $timing-fn 0ms 1 forwards;
}
.in-bottom .info {
  transform-origin: 50% 100%;
  animation: in-bottom $duration $timing-fn 0ms 1 forwards;
}
.in-left .info {
  transform-origin: 0% 0%;
  animation: in-left $duration $timing-fn 0ms 1 forwards;
}

.out-top .info {
  transform-origin: 50% 0%;
  animation: out-top $duration $timing-fn 0ms 1 forwards;
}
.out-right .info {
  transform-origin: 100% 50%;
  animation: out-right $duration $timing-fn 0ms 1 forwards;
}
.out-bottom .info {
  transform-origin: 50% 100%;
  animation: out-bottom $duration $timing-fn 0ms 1 forwards;
}
.out-left .info {
  transform-origin: 0% 0%;
  animation: out-left $duration $timing-fn 0ms 1 forwards;
}

@keyframes in-top {
  from {transform: rotate3d(-1, 0, 0, 90deg);}
  to   {transform: rotate3d(0, 0, 0, 0deg);}}
@keyframes in-right {
  from {transform: rotate3d(0, -1, 0, 90deg);}
  to   {transform: rotate3d(0, 0, 0, 0deg);}}
@keyframes in-bottom {
  from {transform: rotate3d(1, 0, 0, 90deg);}
  to   {transform: rotate3d(0, 0, 0, 0deg);}}
@keyframes in-left {
  from {transform: rotate3d(0, 1, 0, 90deg);}
  to   {transform: rotate3d(0, 0, 0, 0deg);}}

@keyframes out-top {
  from {transform: rotate3d(0, 0, 0, 0deg);}
  to   {transform: rotate3d(-1, 0, 0, 102deg);}}
@keyframes out-right {
  from {transform: rotate3d(0, 0, 0, 0deg);}
  to   {transform: rotate3d(0, -1, 0, 102deg);}}
@keyframes out-bottom {
  from {transform: rotate3d(0, 0, 0, 0deg);}
  to   {transform: rotate3d(1, 0, 0, 101deg);}}
@keyframes out-left {
  from {transform: rotate3d(0, 0, 0, 0deg);}
  to   {transform: rotate3d(0, 1, 0, 102deg);}}