XRWebGLSubImage: imageIndex property

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 read-only imageIndex property of the XRWebGLSubImage interface is a number representing the offset into the texture array if the layer was requested with texture-array; null otherwise.

Value

A number or null if the layer wasn't requested with texture-array.

Using imageIndex

The imageIndex property can be passed WebGL2RenderingContext.framebufferTextureLayer() to attach the depth and color textures to a framebuffer with the correct layer index.

js
const xrGlBinding = new XRWebGLBinding(xrSession, gl);
const layer = xrGlBinding.createProjectionLayer({
  textureType: "texture-array",
});
const framebuffer = gl.createFramebuffer();

xrSession.updateRenderState({ layers: [layer] });
xrSession.requestAnimationFrame(onXRFrame);

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

  gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
  const viewport = xrGlBinding.getSubImage(layer, xrFrame).viewport;
  gl.viewport(viewport.x, viewport.y, viewport.width, viewport.height);

  for (const view in xrViewerPose.views) {
    const subImage = xrGlBinding.getViewSubImage(layer, view);
    gl.framebufferTextureLayer(
      gl.FRAMEBUFFER,
      gl.COLOR_ATTACHMENT0,
      subImage.colorTexture,
      0,
      subImage.imageIndex,
    );
    gl.framebufferTextureLayer(
      gl.FRAMEBUFFER,
      gl.DEPTH_ATTACHMENT,
      subImage.depthStencilTexture,
      0,
      subImage.imageIndex,
    );

    // Render from the viewpoint of xrView
  }
}

Specifications

Specification
WebXR Layers API Level 1
# dom-xrwebglsubimage-imageindex

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
imageIndex
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