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HTML

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HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

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CSS

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CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

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JavaScript

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JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

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Babel includes JSX processing.

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HTML 

              
                 
<body>
  <script>

    (() => {
      const vert = `#version 300 es
      layout(location = 0) in vec3 position;
      out vec2 uv;
      void main(void) {
        uv = position.xy * 0.5 + 0.5;
        gl_Position = vec4(position, 1.0);
      }
      `;

      const frag1 = `#version 300 es
      precision highp float;
      uniform float time;
      uniform float dx;
      uniform float dy;

      float w2 = 1.0 / float(${innerWidth * 2});
      float w10 = 1.0 / (float(${innerWidth * 2}) * 100.); 
      float convert = 3.141592653589 / 180.;

      float sn;
      float cs;
      
      out vec4 fragColor;
 
      void main(void) {
        vec2 uv = gl_FragCoord.xy / vec2(float(${innerWidth * 2}), float(${innerHeight * 2}));

        float xp = uv.x * float(${innerWidth * 2});
        float yp = (1. - uv.y) * float(${innerHeight * 2});
        int x = 10 | 2;
        int xp2 = int(xp) << 1; 
        float t = mod(float(int(yp) | int(xp + yp * .1) ) * (xp + dx) * (w10), 6.283185307179586);
        
        if (t < 0.) {
          sn = 1.27323954 * t + .405284735 * t * t; 
        } else {
          sn = 1.27323954 * t - 0.405284735 * t * t;
        }
        
        t = mod(float( (xp2 | int(yp + xp * .1 + dy) )) * convert, 6.283185307179586);
        
        t += 1.57079632;
        if (t > 3.14159265) {
          t -= 6.28318531;
        }
        if (t < 0.) {
          cs = 1.27323954 * t + 0.405284735 * t * t;
        } else {
          cs = 1.27323954 * t - 0.405284735 * t * t;
        }

        float c1 = 30. * (sn - cs);
 
        if (c1 < 0.) c1 = 255. - c1;
        c1 = float((int(c1) << 4 | int(c1)) & 255) / 255.;
   
        fragColor = vec4(c1, c1, c1, 1.0);
      } 
      `;

      const frag2 = `#version 300 es
      precision highp float;
      in vec2 uv;

       // The max kernel size (impacts performance)
#define maxKernel 1.0

// The max offset (doesn't impact performance)
#define maxOffset 34.0
      uniform sampler2D uTexture; 

      
// https://www.shadertoy.com/view/mdGcRh
vec3 fastBlur(vec2 uv, vec2 texel, vec2 kd)
{
  float r = kd.x * kd.y;
  float rr = 1.0/r;
  vec3 col = vec3(0.0);
  float a = 1.0;

  for (float x = -r; x <= r; x += kd.y) {       
    for (float y = -r; y <= r; y += kd.y)  {
      a++;
      vec2 c = uv + vec2(x,y) * texel;
      col += texture(uTexture, c + fract(sin(dot(c, vec2(12.9898, 78.233))) * 43758.5453) * texel * kd.y * 2.0 - kd.yy * texel).rgb * (2.0 - distance(vec2(x,y) * rr, vec2(0.0))); 
    }
  }
 
  return col / a;
}


      out vec4 fragColor;
      void main(void) {
        vec4 color = texture(uTexture, uv);
        vec4 colorB = texture(uTexture, vec2(uv.x, 1. - uv.y));
        vec3 result = (color.rgb - colorB.rgb) * 1.2;

          float amt = .4;
         vec2 texel = vec2(1.0)/ vec2(float(${innerWidth * 2}), float(${innerHeight * 2}));
    
         vec2 kd = round(vec2(amt * maxKernel + 1.0, amt * maxOffset + 1.0));
    
         vec3 blur = fastBlur(uv, texel, kd);

        fragColor = vec4(result, color.a);
      }
      `;

       const frag3 = `#version 300 es
      precision highp float;
      in vec2 uv;

       // The max kernel size (impacts performance)
#define maxKernel 4.0

// The max offset (doesn't impact performance)
#define maxOffset 34.0
      uniform sampler2D uTexture; 

      
// https://www.shadertoy.com/view/mdGcRh
vec3 fastBlur(vec2 uv, vec2 texel, vec2 kd)
{
  float r = kd.x * kd.y;
  float rr = 1.0/r;
  vec3 col = vec3(0.0);
  float a = 1.0;

  for (float x = -r; x <= r; x += kd.y) {       
    for (float y = -r; y <= r; y += kd.y)  {
      a++;
            vec2 c = uv + vec2(x,y) * texel;

            col += texture(
            
            uTexture, 
            
            c 
            + fract(sin(dot(c, vec2(2.9898, 78.233))) * 13758.5453) * texel * kd.y * 2.4
            - kd.yy * texel
            
            ).rgb * (2.0 - distance(vec2(x,y) * rr, vec2(0.0)));
    }
  }
 
  return col / a;
}


      out vec4 fragColor;
      void main(void) {
        vec4 color = texture(uTexture, uv);

          float amt = .4;
         vec2 texel = vec2(1.0)/ vec2(float(${innerWidth * 2}), float(${innerHeight * 2}));
    
         vec2 kd = round(vec2(amt * maxKernel + 1.0, amt * maxOffset + 1.0));
    
        vec4 blur = vec4(fastBlur(uv, texel, kd), 1.);
          //1-(1-A)*(1-B)
        vec3 f = 1. - (1. - color.rgb) * (1. - blur.rgb);  
       

        fragColor = vec4(f.rgb, 1.);
      } 
      `;

       

      document.body.style.background = '#000';
      const gl = document.body
        .appendChild(document.createElement('canvas'))
        .getContext('webgl2');

      Object.assign(gl.canvas.style, {
        position: 'absolute',
        left: 0,
        top: 0
      });

      const s = 1;
      const verts = new Float32Array([
        -s, -s, 0,
        s, -s, 0,
        -s, s, 0,
        s, s, 0,
      ]);

      const buffer = gl.createBuffer();
      gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
      gl.bufferData(gl.ARRAY_BUFFER, verts, gl.STATIC_DRAW);

      function createShaderProgram(vertexSource, fragmentSource) {
        const vs = gl.createShader(gl.VERTEX_SHADER);
        gl.shaderSource(vs, vertexSource);
        gl.compileShader(vs);

        const fs = gl.createShader(gl.FRAGMENT_SHADER);
        gl.shaderSource(fs, fragmentSource);
        gl.compileShader(fs);

        const program = gl.createProgram();
        gl.attachShader(program, vs);
        gl.attachShader(program, fs);
        gl.linkProgram(program);

        if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
          console.error('Could not link program:', gl.getProgramInfoLog(program));
        }

        return program;
      }

      const program1 = createShaderProgram(vert, frag1);
      const program2 = createShaderProgram(vert, frag2);
      const program3 = createShaderProgram(vert, frag3);
 
      const framebuffer1 = gl.createFramebuffer();
      const framebuffer2 = gl.createFramebuffer();
      const texture1 = gl.createTexture();
      const texture2 = gl.createTexture();

      gl.bindTexture(gl.TEXTURE_2D, texture1);
      gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, innerWidth, innerHeight, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);

      gl.bindTexture(gl.TEXTURE_2D, texture2);
      gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, innerWidth, innerHeight, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);

      gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer1);
      gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture1, 0);

      gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer2);
      gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture2, 0);

      const onResize = () => {
        gl.canvas.width = innerWidth * 2;
        gl.canvas.height = innerHeight * 2;
        gl.canvas.style.width = innerWidth + 'px'
        gl.canvas.style.height = innerHeight + 'px'
        gl.viewport(0, 0, innerWidth * 2, innerHeight * 2);
        gl.bindTexture(gl.TEXTURE_2D, texture1);
        gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, innerWidth * 2, innerHeight * 2, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
        gl.bindTexture(gl.TEXTURE_2D, texture2);
        gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, innerWidth * 2, innerHeight * 2, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
      };

      window.onresize = onResize;
      onResize();

      gl.disable(gl.DEPTH_TEST);

      let mx = 0;
      let my = 0;
      let dx = 0;
      let dy = 0;

      window.onpointermove = e => {
        mx = e.clientX;
        my = e.clientY;
      };

      const loop = () => {

        dx += (mx * 2 - (innerWidth) - dx) / 8;
        dy += (my * 2 - dy) / 8;

        // First pass
        gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer1);
        gl.useProgram(program1);

        const mxUniform = gl.getUniformLocation(program1, 'dx');
        gl.uniform1f(mxUniform, dx);

        const myUniform = gl.getUniformLocation(program1, 'dy');
        gl.uniform1f(myUniform, dy);

        gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
        const pos1 = gl.getAttribLocation(program1, 'position');
        gl.enableVertexAttribArray(pos1);
        gl.vertexAttribPointer(pos1, 3, gl.FLOAT, false, 0, 0);
        gl.clearColor(0, 0, 0, 1);
        gl.clear(gl.COLOR_BUFFER_BIT);
        gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);

         // Second pass
        gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer2);
        gl.useProgram(program2);
        gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
        const pos2 = gl.getAttribLocation(program2, 'position');
        gl.enableVertexAttribArray(pos2);
        gl.vertexAttribPointer(pos2, 3, gl.FLOAT, false, 0, 0);
        const uTexture = gl.getUniformLocation(program2, 'uTexture');
        gl.uniform1i(uTexture, 0);
        gl.activeTexture(gl.TEXTURE0);
        gl.bindTexture(gl.TEXTURE_2D, texture1);
        gl.clearColor(0, 0, 0, 1);
        gl.clear(gl.COLOR_BUFFER_BIT);
        gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);

        
         // third pass
        gl.bindFramebuffer(gl.FRAMEBUFFER, null);
        gl.useProgram(program3);
        gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
        const pos3 = gl.getAttribLocation(program3, 'position');
        gl.enableVertexAttribArray(pos3);
        gl.vertexAttribPointer(pos3, 3, gl.FLOAT, false, 0, 0);
        const u2Texture = gl.getUniformLocation(program3, 'uTexture');
        gl.uniform1i(u2Texture, 0);
        gl.activeTexture(gl.TEXTURE0);
        gl.bindTexture(gl.TEXTURE_2D, texture2);
        gl.clearColor(0, 0, 0, 1);
        gl.clear(gl.COLOR_BUFFER_BIT);
        gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4); 

        requestAnimationFrame(loop);
      };
      loop();
    })();
  </script>
</body>
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