repa-shader

Web component to render webgl shaders

I'm planning to create a custom web component to easily embed fragment shaders to any website for a long time. Here it is finally - now that webgpu appeared, so I can move on to create something similar with that ;)

I've tried to create <repa-component> to be TWIGL compatible, supporting (and more-or-less autodetecting) geekest mode and MRT as well. (But it supports only 300 es mode.)

Basic usage

Include the repa-shader.js module in your HTML, then add your fragment shader code into a <repa-shader> element. That's it. Here's a simple red background:

<script type="module" src="repa-shader.js"></script>
<repa-shader width=400 height=400>
void main() {
  outColor = vec4(1.0, 0.0, 0.0, 1.0);
}
</repa-shader>

You can include your shader code in <script type="x-shader/x-fragment">[your code here]</script> tags as well, in this way you can override the default vertex shader too (using x-shader/x-fragment type).

<repa-shader>

Supported attributes

• width, height: embedded canvas size
• alpha: trasparent background
• snippets: list of snippets to load
• snippet-prefix: URL prefix of the snippets (/snippets by default)
• mouse: mouse support
• orientation: device orientation support
• mode: shader mode
  • raw: nothing is added, in this way you can embed version 200 shaders too
  • classic: ~ twigl classic 300 es mode
  • geeker: ~ twigl geeker 300 es mode
  • geekest: ~ twigl geekest 300 es mode (noise.glsl snippet automatically included)
• render-target-count: MRT target count
• src: external fragment shader source
• fs-input: id of the input/textarea element containing the shader source

Uniforms

• time float, seconds from start (also available as t)
• frame float, frame number from start (f)
• resolution vec2, shader resolution (r)
• mouse vec3, mouse position + button state (m)
• orientation vec3, device orientation

<repa-texture>

You can add textures using the <repa-texture> component included inside your <repa-shader>.

Attributes

• src: texture source
• ref: id of the referred texture element (like an existing image or video in the page)
• type: texture type - sane autodetection available
  • image
  • video
  • webcam
  • canvas
  • audio
  • shader - other instance of <repa-shader>
  • raw - content provided via JS or as JSON
• min-filter, mag-filter (both set by filter): WebGL filtering
• wrap-s, wrap-t, wrap-r (all set by wrap): WebGL wrapping
• format: WebGL format
• internal-format: WebGL internal format
• t3d: 3d texture

More about filtering/wrapping/formats at MDN

Examples

Demo running in my website

Check the demo folder for more detailed examples.