This code sets up a video element from a depth stream, uploads it to a WebGL texture, and samples that texture in the fragment shader, reconstructing the 16-bit depth values from the red, green and blue channels.

var ext = gl.getExtension("WEBGL_texture_from_depth_video");
if (ext) {
  navigator.getUserMedia({ video: true }, successVideo, failureVideo);
}

var depthVideo;

function successVideo(s) {
  // wire the stream into a <video> element for playback
  depthVideo = document.querySelector('#video');
  depthVideo.src = URL.createObjectURL(s);
  depthVideo.play();
}

// ... later, in the rendering loop ...

if (ext) {
 gl.texImage2D(
     gl.TEXTURE_2D,
     0,
     gl.RGB,
     gl.RGB,
     gl.UNSIGNED_SHORT_5_6_5,
     depthVideo
   );  
}

<script id="fragment-shader" type="x-shader/x-fragment">
  varying vec2 v_texCoord;
  // u_tex points to the texture unit containing the depth texture.
  uniform sampler2D u_tex;
  void main() {
    vec4 floatColor = texture2D(u_tex, v_texCoord);
    vec3 rgb = floatColor.rgb;
    ...
    float depth = 63488. * rgb.r + 2016. * rgb.g + 31. * rgb.b;
    ...
  }
</script>