Edge Glow shader preview: Flowing colour that hugs the edges, like an assistant listening.
ittybitty

Edge Glow

Flowing colour that hugs the edges, like an assistant listening.

Code

The usage always matches the preview, layers and performance settings included. No build step or package.

Copy embed gives one block to paste into any page or site builder, no setup. For your own code: add edge-glow.js, ittybitty-shader.js, runtime.js next to this page. Highlighted values follow the controls.

<!-- Quickest: one element. Size it with CSS; it fills its box. -->
<script type="module" src="./ittybitty-shader.js"></script>
<ittybitty-shader effect="edge-glow" style="width: 100%; aspect-ratio: 16 / 10;"></ittybitty-shader>

<!-- Or with JavaScript, for full control: -->
<canvas id="edge-glow" aria-hidden="true" style="width: 100%; aspect-ratio: 16 / 10; display: block"></canvas>

<script type="module">
  import { edgeGlow } from './edge-glow.js';

  const canvas = document.getElementById('edge-glow');
  const effect = edgeGlow(canvas, {
    showRim: true,
    showHaze: true,
    showWake: true,
    speed: 1,
    width: 16,
    intensity: 1,
    radius: 48,
    listen: 0.6,
    wake: 6,
    from: 'right',
    colourA: '#ff5a2e',
    colourB: '#ff3fa4',
    colourC: '#b04dff',
    colourD: '#4f78ff',
    // Performance
    dpr: 1,
    adaptive: true,
  });

  // Later: effect.set(…), effect.pause(), effect.resume(), effect.destroy()
</script>

Details

A band of vivid, flowing colour round the edges of the canvas: a thin bright rim, a band of colour in shifting patches and hot spots, and a haze that bleeds inward. It swells unevenly as if hearing a voice, and when it wakes a wave of light sweeps in from one side. The middle stays clear, so it sits over any page.

Payload
5.8 KB brotli for edge-glow.js and ittybitty-shader.js and runtime.js, measured at build time. See the method.
Resolution
Device pixel ratio capped at 1: the glow is soft, so it needs no more.
Frame rate
Display rate.
When unseen
Stops rendering when the canvas leaves the viewport or the tab is hidden, and resumes where it left off.
Reduced motion
Shows a single still frame. Controls still update it.
Layers
Up to five effects fuse into one shader and one draw call. Filters such as dithering and halftone process the layers beneath them.
Browsers
Any browser with WebGL2: Chrome and Edge 56+, Firefox 51+, Safari 15+.
Licence
MIT. Copy it, change it, ship it.