<!DOCTYPE HTML>
<title>CSS Test (Transforms): Filter on an element in a preserve-3d scene</title>
<link rel="author" title="L. David Baron" href="https://dbaron.org/">
<link rel="author" title="Google" href="http://www.google.com/">
<link rel="help" href="http://www.w3.org/TR/css-transforms-2/#3d-transform-rendering">
<link rel="help" href="https://drafts.fxtf.org/filter-effects/#FilterProperty">
<meta name="assert" content="The filtered element is rendered correctly without clipping, despite the interesting transform.">
<link rel="match" href="preserve3d-and-filter-with-perspective-ref.html">

<style>

  .scene {
    width: 400px;
    height: 400px;
    position: absolute;
    left: 100px;
    top: 100px;
    perspective:1300px;
  }

  .chair {
    width: 400px;
    height: 400px;
    transform: rotateY(88deg);
    transform-style: preserve-3d;
    transform-origin: 50% 50% 50%;
  }

  .shadow {
    position: absolute;
    top: 250px;
    left: 0;
    width: 200px;
    height: 200px;
    filter: blur(1px);
    background: black;
    transform: rotateX(90deg) translate3d(0,-60px,0);
  }

  svg.cover {
    position: absolute;
    z-index: 1;
    top: 0;
    left: 0;
    width: 500px;
    height: 500px;
  }

</style>

<!--

The overall transform here from the viewport to the
<div class="shadow"></div> is:

translate(100px, 100px) translate(200px, 200px) perspective(1300px) translate(-200px, -200px) translate(200px, 200px) rotateY(88deg) translate(-200px, -200px) translateY(250px) translate(100px, 100px) rotateX(90deg) translate3d(0, -60px, 0) translate(-100px, -100px)

which according to https://codepen.io/milosdjakonovic/pen/QyqJyp
is equivalent to the matrix:

matrix3d(0.265528, 0.230629, -0.999391, 0.000768762,
         0.991337, -0.00805373, 0.0348995, -2.68458e-05,
         6.07019e-17, -1, 2.13698e-18, -1.64383e-21,
         88.2804, 405.163, 194.294, 0.850543)

[ 0.265528 0.991337 6.07019e-17 88.2804 ]
[ 0.230629 -0.00805373 -1 405.163 ]
[ -0.999391 0.0348995 2.13698e-18 194.294 ]
[ 0.000768762 -2.68458e-05 -1.64383e-21 0.850543 ]

-->

<div class="scene">
 <div class="chair">
  <div class="shadow"></div>
 </div>
</div>

<!-- cover the blurred edge so we can match to a reference -->
<svg class="cover">
  <polygon fill="transparent" stroke="blue" stroke-width="11"
           points="103.793,476.3579
                   140.7813,449.3585
                   340.0185,450.1613
                   339.0401,477.4783" />
</svg>