aframe-html-shader

A shader to render DOM Element for A-Frame VR.

Usage no npm install needed!

<script type="module">
  import aframeHtmlShader from 'https://cdn.skypack.dev/aframe-html-shader';
</script>

README

A-Frame HTML Shader

A shader to render 2D HTML and CSS to a texture for A-Frame.

Inspired by:

DEMO

example

The screenshot of the HTML element is done via html2canvas. To learn more about the library, check out html2canvas's documentation

Properties

  • A-Frame's basic material properties still supported (e.g., side, transparent).
  • width and height are sizes to capture. For example, if the HTML element's dimensions are 640x480 and width: 200; height: 100, then the rendered HTML canvas will be cropped to 200px width and 100px height from the left-top position.
  • fps is the framerate to render per second. If we only need to render once and be static, we can keep the value at 0.
  • ratio lets us use the HTML element's natural aspect ratio. If we keep the value as null, the generated canvas will scaled for fit to the entity's geometry. If we set ratio: width, the geometry's height will be changed to match the HTML element's ratio, and vice-versa for ratio: height.
Property Description Default Value
target DOM element to render, given by a CSS selector (e.g., #foo). null
width Width to capture. Target's width
height height to capture. Target's height
fps FPS to render. For example, providing 10 will refresh the material against the HTML 10 times per second. By default, the material will be static. 0
ratio Use target's ratio (i.e., width, height). height
debug For debugging purposes, a DOM element which to append a rendered canvas to. Provided via a CSS selector (e.g., #debug). debug DOM to append generated canvas from html2canvas null

For reference, check out the following links:

Available options by html2canvas will be ready for properties soon.

Limitations

We will often see that the rendered looks different from how the source HTML in 2D. The process takes trial-and-error and can also depend on the device.

To check what is actually rendered by html2canvas, set the debug property to append and view the generated canvas. More for limitations, see html2canvas's documentation on limitations.

Method

The following method is coming soon:

  • render() (This is useful when you set fps as 0)

Events

The following events are coming soon:

  • html-ready when html2canvas set and ready to render
  • html-draw each time it renders

Visibility

For the conversion to canvas to work, we need to make the target HTML element technically visible and within the viewport, but we also don't want it to get in the way of our scene. We usually want to give the HTML element a fixed position and z-index it under everything:

<div id="targetHTML" style="width: 100%; height: 100%; position: fixed; left: 0; top: 0; z-index: -1; overflow: hidden"></div>

Usage

Browser Installation

Install and use by directly including the browser files:

<head>
  <title>My A-Frame Scene</title>
  <script src="https://aframe.io/releases/0.5.0/aframe.min.js"></script>
  <script src="https://unpkg.com/aframe-html-shader@0.5.0/dist/aframe-html-shader.min.js"></script>
</head>

<body>
  <a-scene>
    <a-entity geometry="primitive: box" material="shader: html; target: #htmlElement"></a-entity>
  </a-scene>

  <div style="width: 100%; height: 100%; position: fixed; left: 0; top: 0; z-index: -1; overflow: hidden">
    <div id="htmlElement" style="background: #F8F8F8; color: #333; font-size: 48px">Hello, HTML!</div>
  </div>
</body>

NPM Installation

Install via NPM:

npm install --save aframe-html-shader

Then register and use.

import 'aframe'
import 'aframe-html-shader'