JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//cdn.rawgit.com/mrdoob/three.js/master/build/three.min.js"></script>
<script src="https://abberg.github.io/lib/shaders/CopyShader.js"></script>
<script src="https://abberg.github.io/lib/postprocessing/EffectComposer.js"></script>
<script src="https://abberg.github.io/lib/postprocessing/RenderPass.js"></script>
<script src="https://abberg.github.io/lib/postprocessing/ShaderPass.js"></script>

JavaScript

THREE.VolumetericLightShader = {
  uniforms: {
    tDiffuse: {value:null},
    lightPosition: {value: new THREE.Vector2(0.5, 0.5)},
    exposure: {value: 0.18},
    decay: {value: 0.95},
    density: {value: 0.8},
    weight: {value: 0.4},
    samples: {value: 50}
  },

  vertexShader: [
    "varying vec2 vUv;",
    "void main() {",
      "vUv = uv;",
      "gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",
    "}"
  ].join("\n"),

  fragmentShader: [
    "varying vec2 vUv;",
    "uniform sampler2D tDiffuse;",
    "uniform vec2 lightPosition;",
    "uniform float exposure;",
    "uniform float decay;",
    "uniform float density;",
    "uniform float weight;",
    "uniform int samples;",
    "const int MAX_SAMPLES = 100;",
    "void main()",
    "{",
      "vec2 texCoord = vUv;",
      "vec2 deltaTextCoord = texCoord - lightPosition;",
      "deltaTextCoord *= 1.0 / float(samples) * density;",
      "vec4 color = texture2D(tDiffuse, texCoord);",
      "float illuminationDecay = 1.0;",
      "for(int i=0; i < MAX_SAMPLES; i++)",
      "{",
        "if(i == samples){",
          "break;",
        "}",
        "texCoord -= deltaTextCoord;",
        "vec4 sample = texture2D(tDiffuse, texCoord);",
        "sample *= illuminationDecay * weight;",
        "color += sample;",
        "illuminationDecay *= decay;",
      "}",
      "gl_FragColor = color * exposure;",
    "}"
  ].join("\n")
};

THREE.AdditiveBlendingShader = {
  uniforms: {
    tDiffuse: { value:null },
    tAdd: { value:null }
  },

  vertexShader: [
    "varying vec2 vUv;",
    "void main() {",
      "vUv = uv;",
      "gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",
    "}"
  ].join("\n"),

  fragmentShader: [
    "uniform sampler2D tDiffuse;",
    "uniform sampler2D tAdd;",
    "varying vec2 vUv;",
    "void main() {",
      "vec4 color = texture2D( tDiffuse, vUv );",
      "vec4 add = texture2D( tAdd, vUv );",
      "gl_FragColor = color + add;",
 ...