CodePen Embed - WebGL Distortion Slider

<body class="loading">

  <!-- add karla font -->

  <header>
    <div class="inner">
      <div class="logo"><img src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/123024/wwf-logo.png"></div>
      <div class="burger"></div>
      <nav>
        <a class="active" href="#">Species</a>
        <a href="#">About Us</a>
        <a href="#">Our Work</a>
        <a href="#">Get Involved</a>
      </nav>
      <a href="#" class="donate-link">Donate</a>
    </div>
  </header>

  <main>
    <div id="slider">

      <div class="slider-inner">
        <div id="slider-content">
          <div class="meta">Species</div>
          <h2 id="slide-title">Amur <br>Leopard</h2>
          <span data-slide-title="0">Amur <br>Leopard</span>
          <span data-slide-title="1">Asiatic <br>Lion</span>
          <span data-slide-title="2">Siberian <br>Tiger</span>
          <span data-slide-title="3">Brown <br>Bear</span>
          <div class="meta">Status</div>
          <div id="slide-status">Critically Endangered</div>
          <span data-slide-status="0">Critically Endangered</span>
          <span data-slide-status="1">Endangered</span>
          <span data-slide-status="2">Endangered</span>
          <span data-slide-status="3">Least Concern</span>
        </div>
      </div>

      <img src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/123024/leopard2.jpg" />
      <img src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/123024/lion2.jpg" />
      <img src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/123024/tiger2.jpg" />
      <img src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/123024/bear2.jpg" />

      <div id="pagination">
        <button class="active" data-slide="0"></button>
        <button data-slide="1"></button>
        <button data-slide="2"></button>
        <button data-slide="3"></button>
      </div>

    </div>
  </main>
  
  <!-- Global site tag (gtag.js) - Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=UA-40525870-5"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());

  gtag('config', 'UA-40525870-5');
</script>

  </body>

article,aside,details,figcaption,figure,footer,header,hgroup,main,nav,section,summary{display:block;}audio,canvas,video{display:inline-block;}audio:not([controls]){display:none;height:0;}[hidden]{display:none;}html{font-family:sans-serif;-ms-text-size-adjust:100%;-webkit-text-size-adjust:100%;}body{margin:0;}a:focus{outline:thin dotted;}a:active,a:hover{outline:0;}h1{font-size:2em;margin:0.67em 0;}abbr[title]{border-bottom:1px dotted;}b,strong{font-weight:bold;}dfn{font-style:italic;}hr{-moz-box-sizing:content-box;box-sizing:content-box;height:0;}mark{background:#ff0;color:#000;}code,kbd,pre,samp{font-family:monospace,serif;font-size:1em;}pre{white-space:pre-wrap;}q{quotes:"\201C" "\201D" "\2018" "\2019";}small{font-size:80%;}sub,sup{font-size:75%;line-height:0;position:relative;vertical-align:baseline;}sup{top:-0.5em;}sub{bottom:-0.25em;}img{border:0;}svg:not(:root){overflow:hidden;}figure{margin:0;}fieldset{border:1px solid #c0c0c0;margin:0 2px;padding:0.35em 0.625em 0.75em;}legend{border:0;padding:0;}button,input,select,textarea{font-family:inherit;font-size:100%;margin:0;}button,input{line-height:normal;}button,select{text-transform:none;}button,html input[type="button"],input[type="reset"],input[type="submit"]{-webkit-appearance:button;cursor:pointer;}button[disabled],html input[disabled]{cursor:default;}input[type="checkbox"],input[type="radio"]{box-sizing:border-box;padding:0;}input[type="search"]{-webkit-appearance:textfield;-moz-box-sizing:content-box;-webkit-box-sizing:content-box;box-sizing:content-box;}input[type="search"]::-webkit-search-cancel-button,input[type="search"]::-webkit-search-decoration{-webkit-appearance:none;}button::-moz-focus-inner,input::-moz-focus-inner{border:0;padding:0;}textarea{overflow:auto;vertical-align:top;}table{border-collapse:collapse;border-spacing:0;}
*,
*::after,
*::before {
  box-sizing: border-box;
}

::selection {
  background-color: grey;
  color: white;
}

::-moz-selection {
  background-color: grey;
  color: white;
}

@import url("https://use.typekit.net/euz1eqv.css");

html {
  background: #fff;
  -moz-osx-font-smoothing: grayscale;
  -webkit-font-smoothing: antialiased;
}

body {
  background-color: #23272A;
  overflow: hidden;
}

header {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 115px;
  z-index: 10;
  background-image: url(https://s3-us-west-2.amazonaws.com/s.cdpn.io/123024/menutexture.png);
  background-position: center top;
  background-size: auto 200px;
  background-repeat: repeat-x;

  .inner {
    max-width: 1060px;
    margin: 0 auto;
    display: flex;
    height: 70px;
    align-items: center;
    justify-content: center;
    position: relative;
  }

  .logo {
    display: block;
    width: 76px;
    height: 90px;
    position: absolute;
    top: 0;
    left: 0;
    background-color: white;
    text-align: center;

    img {
      width: 45px;
      margin-top: 10px;
    }
  }

  nav {
    display: none;

    a {
      font-family: 'Arial', serif;
      font-size: 12px;
      color: #8c8c8e;
      text-transform: uppercase;
      letter-spacing: 3px;
      text-decoration: none;
      margin: 0 18px;

      &.active, &:hover {
        color: white;
      }
    }

    @media screen and (min-width: 800px) {
      display: block;
    }
  }

  .burger {
    display: block;
    position: relative;
    top: -6px;
    padding-left: 30px;

    &:before {
      content: "";
      position: absolute;
      left: 0;
      top: 0;
      width: 30px;
      height: 2px;
      background: white;
      box-shadow: 0 12px 0 0 white, 0 6px 0 0 white;
    }

    @media screen and (min-width: 800px) {
      display: none;
    }
  }

  .donate-link {
    width: 72px;
    text-align: center;
    position: absolute;
    right: 10px;
    top: 27px;
    font-family: 'Arial', sans-serif;
    font-size: 12px;
    color: white;
    text-transform: uppercase;
    letter-spacing: 3px;
    text-decoration: none;
    padding-bottom: 6px;
    border-bottom: 2px solid rgba(255, 255, 255, 0.3);
  }
}

main {
  position: relative;
  width: 100%;
  height: 100vh;
}

#slider {
  width: 100%;
  max-width: 1200px;
  height: 100%;
  margin: 0 auto;
  position: relative;

  canvas {
    width: 150%;
    height: 150%;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 2;
  }

  img {
    width: 100%;
    max-width: 100%;
    position: relative;
    z-index: 0;
  }
}

.slider-inner {
  position: relative;
  display: flex;
  align-items: center;
  width: 100%;
  max-width: 1060px;
  height: 100%;
  margin: 0 auto;
  z-index: 5;
}

#slider-content {
  padding: 0 10px;

  h2 {
    font-family: 'acta-display', serif;
    font-weight: 400;
    font-size: 30px;
    letter-spacing: -1px;
    color: white;
    line-height: 30px;
    margin: 20px 0 60px;

    @media screen and (min-width: 800px) {
      font-size: 110px;
      line-height: 100px;
    }
  }

  span {
    display: none;
  }

  .meta {
    display: inline-block;
    font-family: 'Arial', sans-serif;
    font-size: 11px;
    letter-spacing: 5px;
    color: #88888a;
    text-transform: uppercase;
    position: relative;

    @media screen and (min-width: 800px) {
      font-size: 13px;
    }

    &:after {
      content: '';
      display: block;
      position: absolute;
      top: 5px;
      right: -55px;
      width: 45px;
      height: 2px;
      background-color: #393d40;
    }
  }

  #slide-status {
    margin-top: 10px;
    font-family: 'acta-display', serif;
    font-weight: 400;
    font-size: 18px;
    color: white;

    @media screen and (min-width: 800px) {
      font-size: 34px;
    }
  }
}

#pagination {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  right: 30px;
  z-index: 6;

  button {
    display: block;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    border: 0;
    width: 16px;
    height: 16px;
    background-color: #FFFFFF;
    border-radius: 100%;
    padding: 0;
    margin: 30px 0;
    cursor: pointer;
    position: relative;
    opacity: 0.2;
    transition: opacity 0.2s ease-in-out;
    outline: none;

    &:hover {
      opacity: 0.5;
    }

    &.active {
      opacity: 1;

      &:before {
        width: 300%;
        height: 300%;
        opacity: 1;
      }
    }

    &:before {
      content: '';
      display: block;
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      width: 100%;
      height: 100%;
      border-radius: 100%;
      border: 1px solid rgba(255, 255, 255, 0.2);
      opacity: 0;
      transition: opacity 0.4s ease-in-out, width 0.4s ease-in-out, height 0.4s ease-in-out;
    }
  }
}

/* Page Loader */
.loading {

  &:before {
    content: '';
    position: fixed;
    z-index: 100000;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: black;
  }

  &:after {
    content: '';
    position: fixed;
    z-index: 100000;
    top: 50%;
    left: 50%;
    width: 60px;
    height: 60px;
    margin: -30px 0 0 -30px;
    pointer-events: none;
    border-radius: 50%;
    opacity: 0.4;
    background: white;
    animation: loaderAnim 0.7s linear infinite alternate forwards;
  }
}

@keyframes loaderAnim {
  to {
    opacity: 1;
    transform: scale3d(0.5,0.5,1);
  }
}

View Compiled

const displacementSlider = function(opts) {

    let vertex = `
        varying vec2 vUv;
        void main() {
          vUv = uv;
          gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
        }
    `;

    let fragment = `
        
        varying vec2 vUv;

        uniform sampler2D currentImage;
        uniform sampler2D nextImage;

        uniform float dispFactor;

        void main() {

            vec2 uv = vUv;
            vec4 _currentImage;
            vec4 _nextImage;
            float intensity = 0.3;

            vec4 orig1 = texture2D(currentImage, uv);
            vec4 orig2 = texture2D(nextImage, uv);
            
            _currentImage = texture2D(currentImage, vec2(uv.x, uv.y + dispFactor * (orig2 * intensity)));

            _nextImage = texture2D(nextImage, vec2(uv.x, uv.y + (1.0 - dispFactor) * (orig1 * intensity)));

            vec4 finalTexture = mix(_currentImage, _nextImage, dispFactor);

            gl_FragColor = finalTexture;

        }
    `;

    let images = opts.images, image, sliderImages = [];;
    let canvasWidth = images[0].clientWidth;
    let canvasHeight = images[0].clientHeight;
    let parent = opts.parent;
    let renderWidth = Math.max(document.documentElement.clientWidth, window.innerWidth || 0);
    let renderHeight = Math.max(document.documentElement.clientHeight, window.innerHeight || 0);

    let renderW, renderH;

    if( renderWidth > canvasWidth ) {
        renderW = renderWidth;
    } else {
        renderW = canvasWidth;
    }

    renderH = canvasHeight;

    let renderer = new THREE.WebGLRenderer({
        antialias: false,
    });

    renderer.setPixelRatio( window.devicePixelRatio );
    renderer.setClearColor( 0x23272A, 1.0 );
    renderer.setSize( renderW, renderH );
    parent.appendChild( renderer.domElement );

    let loader = new THREE.TextureLoader();
    loader.crossOrigin = "anonymous";

    images.forEach( ( img ) => {

        image = loader.load( img.getAttribute( 'src' ) + '?v=' + Date.now() );
        image.magFilter = image.minFilter = THREE.LinearFilter;
        image.anisotropy = renderer.capabilities.getMaxAnisotropy();
        sliderImages.push( image );

    });

    let scene = new THREE.Scene();
    scene.background = new THREE.Color( 0x23272A );
    let camera = new THREE.OrthographicCamera(
        renderWidth / -2,
        renderWidth / 2,
        renderHeight / 2,
        renderHeight / -2,
        1,
        1000
    );

    camera.position.z = 1;

    let mat = new THREE.ShaderMaterial({
        uniforms: {
            dispFactor: { type: "f", value: 0.0 },
            currentImage: { type: "t", value: sliderImages[0] },
            nextImage: { type: "t", value: sliderImages[1] },
        },
        vertexShader: vertex,
        fragmentShader: fragment,
        transparent: true,
        opacity: 1.0
    });

    let geometry = new THREE.PlaneBufferGeometry(
        parent.offsetWidth,
        parent.offsetHeight,
        1
    );
    let object = new THREE.Mesh(geometry, mat);
    object.position.set(0, 0, 0);
    scene.add(object);

    let addEvents = function(){

        let pagButtons = Array.from(document.getElementById('pagination').querySelectorAll('button'));
        let isAnimating = false;

        pagButtons.forEach( (el) => {

            el.addEventListener('click', function() {

                if( !isAnimating ) {

                    isAnimating = true;

                    document.getElementById('pagination').querySelectorAll('.active')[0].className = '';
                    this.className = 'active';

                    let slideId = parseInt( this.dataset.slide, 10 );

                    mat.uniforms.nextImage.value = sliderImages[slideId];
                    mat.uniforms.nextImage.needsUpdate = true;

                    TweenLite.to( mat.uniforms.dispFactor, 1, {
                        value: 1,
                        ease: 'Expo.easeInOut',
                        onComplete: function () {
                            mat.uniforms.currentImage.value = sliderImages[slideId];
                            mat.uniforms.currentImage.needsUpdate = true;
                            mat.uniforms.dispFactor.value = 0.0;
                            isAnimating = false;
                        }
                    });

                    let slideTitleEl = document.getElementById('slide-title');
                    let slideStatusEl = document.getElementById('slide-status');
                    let nextSlideTitle = document.querySelectorAll(`[data-slide-title="${slideId}"]`)[0].innerHTML;
                    let nextSlideStatus = document.querySelectorAll(`[data-slide-status="${slideId}"]`)[0].innerHTML;

                    TweenLite.fromTo( slideTitleEl, 0.5,
                        {
                            autoAlpha: 1,
                            y: 0
                        },
                        {
                            autoAlpha: 0,
                            y: 20,
                            ease: 'Expo.easeIn',
                            onComplete: function () {
                                slideTitleEl.innerHTML = nextSlideTitle;

                                TweenLite.to( slideTitleEl, 0.5, {
                                    autoAlpha: 1,
                                    y: 0,
                                })
                            }
                        });

                    TweenLite.fromTo( slideStatusEl, 0.5,
                        {
                            autoAlpha: 1,
                            y: 0
                        },
                        {
                            autoAlpha: 0,
                            y: 20,
                            ease: 'Expo.easeIn',
                            onComplete: function () {
                                slideStatusEl.innerHTML = nextSlideStatus;

                                TweenLite.to( slideStatusEl, 0.5, {
                                    autoAlpha: 1,
                                    y: 0,
                                    delay: 0.1,
                                })
                            }
                        });

                }

            });

        });

    };

    addEvents();

    window.addEventListener( 'resize' , function(e) {
        renderer.setSize(renderW, renderH);
    });

    let animate = function() {
        requestAnimationFrame(animate);

        renderer.render(scene, camera);
    };
    animate();
};

imagesLoaded( document.querySelectorAll('img'), () => {

    document.body.classList.remove('loading');

    const el = document.getElementById('slider');
    const imgs = Array.from(el.querySelectorAll('img'));
    new displacementSlider({
        parent: el,
        images: imgs
    });

});

View Compiled

This Pen is owned by Ash Thornton on CodePen.

See more by @ashthornton on CodePen

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