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                		<!-- div that will hold our WebGL canvas -->
		<div id="canvas"></div>

		<!-- div used to create our plane -->
		<div class="plane">

			<!-- image that will be used as a texture by our plane -->
			<img src="" crossorigin="anonymous"/>

        <script id="plane-vs" type="x-shader/x-vertex">
			#ifdef GL_ES
			precision mediump float;

			// those are the mandatory attributes that the lib sets
			attribute vec3 aVertexPosition;
			attribute vec2 aTextureCoord;

			// those are mandatory uniforms that the lib sets and that contain our model view and projection matrix
			uniform mat4 uMVMatrix;
			uniform mat4 uPMatrix;
      // our texture matrix uniform (this is the lib default name, but it could be changed)
      uniform mat4 uTextureMatrix0;

			// if you want to pass your vertex and texture coords to the fragment shader
			varying vec3 vVertexPosition;
			varying vec2 vTextureCoord;

			void main() {
				vec3 vertexPosition = aVertexPosition;

				gl_Position = uPMatrix * uMVMatrix * vec4(vertexPosition, 1.0);

				// set the varyings
        // thanks to the texture matrix we will be able to calculate accurate texture coords
        // so that our texture will always fit our plane without being distorted
				vTextureCoord = (uTextureMatrix0 * vec4(aTextureCoord, 0.0, 1.0)).xy;
				vVertexPosition = vertexPosition;
        <script id="plane-fs" type="x-shader/x-fragment">
			#ifdef GL_ES
			precision mediump float;

			// get our varyings
			varying vec3 vVertexPosition;
			varying vec2 vTextureCoord;

			// the uniform we declared inside our javascript
			uniform float uTime;

			// our texture sampler (default name, to use a different name please refer to the documentation)
			uniform sampler2D uSampler0;

			void main() {
        // get our texture coords
				vec2 textureCoord = vTextureCoord;

				// displace our pixels along both axis based on our time uniform and texture UVs
				// this will create a kind of water surface effect
				// try to comment a line or change the constants to see how it changes the effect
				// reminder : textures coords are ranging from 0.0 to 1.0 on both axis
				const float PI = 3.141592;

				textureCoord.x += (
					sin(textureCoord.x * 10.0 + ((uTime * (PI / 3.0)) * 0.031))
					+ sin(textureCoord.y * 10.0 + ((uTime * (PI / 2.489)) * 0.017))
					) * 0.0075;

				textureCoord.y += (
					sin(textureCoord.y * 20.0 + ((uTime * (PI / 2.023)) * 0.023))
					+ sin(textureCoord.x * 20.0 + ((uTime * (PI / 3.1254)) * 0.037))
					) * 0.0125;

				gl_FragColor = texture2D(uSampler0, textureCoord);

		<script src="" type="text/javascript"></script>


                body {
  /* make the body fits our viewport */
  position: relative;
  width: 100%;
  height: 100vh;
  margin: 0;
  /* hide scrollbars */
  overflow: hidden;

#canvas {
  /* make the canvas wrapper fits the window */
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;

.plane {
  /* define the size of your plane */
  width: 80%;
  max-width: 1400px;
  height: 80vh;
  position: relative;
  top: 10vh;
  margin: 0 auto;
  overflow: hidden;

.plane img {
  /* hide the img element */
  display: none;

/*** in case of error show the image ***/

.no-curtains .plane {
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;

.no-curtains .plane img {
  display: block;
  max-width: 100%;
  object-fit: cover;


                window.onload = function() {
  // set up our WebGL context and append the canvas to our wrapper
  var webGLCurtain = new Curtains({
    container: "canvas"
  // if there's any error during init, we're going to catch it here
  webGLCurtain.onError(function() {
    // we will add a class to the document body to display original images

  // get our plane element
  var planeElement = document.getElementsByClassName("plane")[0];

  // set our initial parameters (basic uniforms)
  var params = {
    vertexShaderID: "plane-vs", // our vertex shader ID
    fragmentShaderID: "plane-fs", // our framgent shader ID
    //crossOrigin: "", // codepen specific
    uniforms: {
      time: {
        name: "uTime", // uniform name that will be passed to our shaders
        type: "1f", // this means our uniform is a float
        value: 0,

  // create our plane mesh
  var plane = webGLCurtain.addPlane(planeElement, params);

  // if our plane has been successfully created
  // we use the onRender method of our plane fired at each requestAnimationFrame call
  plane && plane.onRender(function() {
    plane.uniforms.time.value++; // update our time uniform value