VRDisplay.requestPresent()

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

The requestPresent() method of the VRDisplay interface starts the VRDisplay presenting a scene.

Syntax

vrDisplayInstance.requestPresent(layers).then(function() {
  // Do something after the presentation has begun
});

Parameters

layers
An array of VRLayerInit objects representing the scene you want to present. At the moment, this can be a minimum of 0 and a maximum of 1.

Return value

A promise that resolves once the presentation has begun. there are a number of rules surrounding the promise's fulfillment or rejection:

  • If VRDisplayCapabilities.canPresent is false, or if the VRLayer array contains more than VRDisplayCapabilities.maxLayers layers, the promise will be rejected.
  • If the VRDisplay is already presenting when requestPresent() is called, the VRDisplay will update the VRLayer array being presented.
  • If a call to requestPresent() is rejected while the VRDisplay is already presenting it will end its presentation.
  • If requestPresent() is called outside of an engagement gesture the promise will be rejected unless the VRDisplay was already presenting. This engagement gesture is also sufficient to allow requestPointerLock() calls until presentation has ended.

Examples

if(navigator.getVRDisplays) {
  console.log('WebVR 1.1 supported');
  // Then get the displays attached to the computer
  navigator.getVRDisplays().then(function(displays) {
    // If a display is available, use it to present the scene
    if(displays.length > 0) {
      vrDisplay = displays[0];
      console.log('Display found');
      // Starting the presentation when the button is clicked: It can only be called in response to a user gesture
      btn.addEventListener('click', function() {
        if(btn.textContent === 'Start VR display') {
          vrDisplay.requestPresent([{ source: canvas }]).then(function() {
            console.log('Presenting to WebVR display');

            // Set the canvas size to the size of the vrDisplay viewport

            var leftEye = vrDisplay.getEyeParameters('left');
            var rightEye = vrDisplay.getEyeParameters('right');

            canvas.width = Math.max(leftEye.renderWidth, rightEye.renderWidth) * 2;
            canvas.height = Math.max(leftEye.renderHeight, rightEye.renderHeight);

            // stop the normal presentation, and start the vr presentation
            window.cancelAnimationFrame(normalSceneFrame);
            drawVRScene();

            btn.textContent = 'Exit VR display';
          });
        } else {
          vrDisplay.exitPresent();
          console.log('Stopped presenting to WebVR display');

          btn.textContent = 'Start VR display';

          // Stop the VR presentation, and start the normal presentation
          vrDisplay.cancelAnimationFrame(vrSceneFrame);
          drawScene();
        }
      });
    }
  });
}

Note: You can see this complete code at raw-webgl-example.

Specifications

Specification Status Comment
WebVR 1.1
The definition of 'requestPresent()' in that specification.
Draft Initial definition

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic support
Experimental
Chrome No support NoEdge Full support 15Firefox Full support 55
Notes
Full support 55
Notes
Notes Windows support was enabled in Firefox 55.
Full support 63
Notes
Notes macOS support was enabled in Firefox 63.
IE No support NoOpera ? Safari ? WebView Android No support NoChrome Android Full support 56
Notes Disabled
Full support 56
Notes Disabled
Notes Only works in an experimental version of Chrome. (Other builds won't return any devices when Navigator.getVRDisplays() is invoked.)
Notes Daydream View supported in Chrome 56.
Notes Google Cardboard supported in Chrome 57.
Disabled From version 56: this feature is behind the WebVR preference. To change preferences in Chrome, visit chrome://flags.
Edge Mobile ? Firefox Android ? Opera Android ? Safari iOS ? Samsung Internet Android Full support 6.0

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
See implementation notes.
See implementation notes.
User must explicitly enable this feature.
User must explicitly enable this feature.

See also

Document Tags and Contributors

Contributors to this page: fscholz, chrisdavidmills, abbycar
Last updated by: fscholz,