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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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Adding Classes

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Insecure Resource

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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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About Vendor Prefixing

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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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Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

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HTML 

              
                <canvas></canvas>
<div id="controls"></div>
<script id="vs" type="notjs">
uniform mat4 u_worldViewProjection;

attribute vec4 a_position;
attribute vec2 a_texcoord;

varying vec4 v_position;
varying vec2 v_texCoord;

void main() {
  v_texCoord = a_texcoord;
  gl_Position = u_worldViewProjection * a_position;
}
</script>
<script id="fs" type="notjs">
precision mediump float;
uniform sampler2D u_texture;
uniform vec4 u_frontColor;
uniform vec4 u_backColor;
varying vec2 v_texCoord;

void main() {
  gl_FragColor = texture2D(u_texture, v_texCoord) * (gl_FrontFacing ? u_frontColor : u_backColor);
}
</script>
<script src="//twgljs.org/dist/twgl-full.min.js"></script>
!

CSS 

              
                body, html {
  height: 100%;
  margin: 0;
  font-family: monospace;
}
canvas {
  width: 100%;
  height: 100%;
}
#controls {
  position: absolute;
  left: 10px;
  top: 10px;
  z-index: 2;
  background-color: rgba(0,0,0,0.5);
  width: 30%;
  padding: 5px;
}
input[type=range] {
  width: 100%;
  display: block;
}
!

JS 

              
                "use strict";
var m4 = twgl.m4;
var $ = document.getElementById.bind(document);
twgl.setAttributePrefix("a_");
var gl = twgl.getWebGLContext(document.querySelector("canvas"));
                                                 var programInfo = twgl.createProgramInfo(gl, ["vs", "fs"], ["a_position", "a_texcoord"]);

var bufferInfo = twgl.primitives.createSphereBufferInfo(gl, 1, 24, 12);
var bufferInfo2 = twgl.primitives.createCubeBufferInfo(gl, 2);

var textures = twgl.createTextures(gl, {
  // A 2x2 pixel texture from a JavaScript array
  checker: {
    mag: gl.NEAREST,
    min: gl.LINEAR,
    src: [
      255, 255, 255, 255,
      192, 192, 192, 255,
      192, 192, 192, 255,
      255, 255, 255, 255,
    ],
  },
});

var g = {
  zNear: 3,
  zFar: 7,
  fovy: 45,
};

function setupRange(id, value, min, max) {
  var range = document.createElement("input");
  range.type = "range";
  range.value = value;
  range.min = min;
  range.max = max;
  range.step = 0.01;
  var label = document.createElement("label");
  label.appendChild(document.createTextNode(id + ": "));
  var span = document.createTextNode("");
  range.addEventListener('input', function(e) {
    span.nodeValue = e.target.value;
    g[id] = parseFloat(e.target.value);
  });
  span.nodeValue = range.value;
  label.appendChild(span);
  $("controls").appendChild(label);
  $("controls").appendChild(range);
}

setupRange("zNear", 3, 3, 7);
setupRange("zFar", 7, 3, 7);
//setupRange("fovy", 45, 20, 70);

var uniforms = {
  u_worldViewProjection: m4.identity(),
  u_frontColor: [1, 0, 1, 1],
  u_backColor: [0, 1, 1, 1],
  u_texture: textures.checker,
};  

var projection;

function draw(bufferInfo, translation, time) {
  var world =  m4.identity();
  m4.translate(world, translation, world);
  m4.rotateY(world, time, world);
  m4.rotateZ(world, time, world);
  m4.multiply(world, projection, uniforms.u_worldViewProjection);

  twgl.setBuffersAndAttributes(gl, programInfo, bufferInfo);
  twgl.setUniforms(programInfo, uniforms);
  twgl.drawBufferInfo(gl, gl.TRIANGLES, bufferInfo);
}

function render(time) {
  time *= 0.001;
  twgl.resizeCanvasToDisplaySize(gl.canvas);
  gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
  gl.enable(gl.DEPTH_TEST);

  var aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;
  projection = m4.perspective(g.fovy * Math.PI / 180, aspect, g.zNear, g.zFar);
  
  gl.useProgram(programInfo.program);
  
  draw(bufferInfo , [ 2, 0, -5], time);
  draw(bufferInfo2, [-2, 0, -5], time);
  
  requestAnimationFrame(render);
}
requestAnimationFrame(render);
!
999px

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