XRWebGLBinding: getSubImage() method

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The getSubImage() method of the XRWebGLBinding interface returns a XRWebGLSubImage object representing the WebGL texture to render.

Syntax

js
getSubImage(layer, frame)
getSubImage(layer, frame, eye)

Parameters

layer

The XRCompositionLayer to use for rendering (can be all types of XRCompositionLayer objects except XRProjectionLayer, see XRWebGLBinding.getViewSubImage() for rendering projection layers).

frame

The XRFrame frame to use for rendering.

eye Optional

An optional XRView.eye indicating which view's eye to use for rendering. Possible values:

left

The XRView represents the point-of-view of the viewer's left eye.

The view represents the viewer's right eye.

none

The view describes a monoscopic view, or the view otherwise doesn't represent a particular eye's point-of-view. Defaults to none.

Return value

A XRWebGLSubImage object.

Exceptions

A TypeError is thrown,

Examples

Rendering an XRQuadLayer

The following example renders an XRQuadLayer.

js
const xrGlBinding = new XRWebGLBinding(xrSession, gl);
const quadLayer = xrGlBinding.createQuadLayer({
  space: xrReferenceSpace,
  viewPixelWidth: 512,
  viewPixelHeight: 512,
});

// Position 2 meters away from the origin with a width and height of 1.5 meters
quadLayer.transform = new XRRigidTransform({ z: -2 });
quadLayer.width = 1.5;
quadLayer.height = 1.5;

const framebuffer = gl.createFramebuffer();
xrSession.updateRenderState({ layers: [quadLayer] });
xrSession.requestAnimationFrame(onXRFrame);

function onXRFrame(time, xrFrame) {
  xrSession.requestAnimationFrame(onXRFrame);

  gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
  let subImage = xrGlBinding.getSubImage(quadLayer, xrFrame);
  gl.framebufferTexture2D(
    gl.FRAMEBUFFER,
    gl.COLOR_ATTACHMENT0,
    subImage.colorTexture,
    0,
  );
  let viewport = subImage.viewport;
  gl.viewport(viewport.x, viewport.y, viewport.width, viewport.height);

  // Render content for the quad layer
}

Specifications

Specification
WebXR Layers API Level 1
# dom-xrwebglbinding-getsubimage

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
getSubImage
Experimental

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
No support
No support
Experimental. Expect behavior to change in the future.

See also