VRDisplay.requestAnimationFrame()

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The requestAnimationFrame() method of the VRDisplay interface is a special implementation of Window.requestAnimationFrame containing a callback function that will be called every time a new frame of the VRDisplay presentation is rendered:

  • When the VRDisplay is not presenting a scene, this is functionally equivalent to Window.requestAnimationFrame.
  • When the VRDisplay is presenting, the callback is called at its native refresh rate.

Syntax

var handle = vrDisplayInstance.requestAnimationFrame(callback);

Parameters

callback
A callback function that will be called every time a new frame of the VRDisplay presentation is rendered.

Return value

A long representing the handle of the requestAnimationFrame() call. This can then be passed to a VRDisplay.cancelAnimationFrame() call to unregister the callback.

Examples

var frameData = new VRFrameData();
var vrDisplay;

navigator.getVRDisplays().then(function(displays) {
  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() {
    vrDisplay.requestPresent([{ source: canvas }]).then(function() {        
      drawVRScene();
    });
  });
});

// WebVR: Draw the scene for the WebVR display.
function drawVRScene() {
  // WebVR: Request the next frame of the animation
  vrSceneFrame = vrDisplay.requestAnimationFrame(drawVRScene);

  // Populate frameData with the data of the next frame to display
  vrDisplay.getFrameData(frameData);

  // You can get the position, orientation, etc. of the display from the current frame's pose
  var curFramePose = frameData.pose;
  var curPos = curFramePose.position;
  var curOrient = curFramePose.orientation;

  // Clear the canvas before we start drawing on it.

  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

  // WebVR: Create the required projection and view matrix locations needed
  // for passing into the uniformMatrix4fv methods below

  var projectionMatrixLocation = gl.getUniformLocation(shaderProgram, "projMatrix");
  var viewMatrixLocation = gl.getUniformLocation(shaderProgram, "viewMatrix");

  // WebVR: Render the left eye’s view to the left half of the canvas
  gl.viewport(0, 0, canvas.width * 0.5, canvas.height);
  gl.uniformMatrix4fv(projectionMatrixLocation, false, frameData.leftProjectionMatrix);
  gl.uniformMatrix4fv(viewMatrixLocation, false, frameData.leftViewMatrix);
  drawGeometry();

  // WebVR: Render the right eye’s view to the right half of the canvas
  gl.viewport(canvas.width * 0.5, 0, canvas.width * 0.5, canvas.height);
  gl.uniformMatrix4fv(projectionMatrixLocation, false, frameData.rightProjectionMatrix);
  gl.uniformMatrix4fv(viewMatrixLocation, false, frameData.rightViewMatrix);
  drawGeometry();

  function drawGeometry() {
    // draw the view for each eye 
  }

    ...

  // WebVR: Indicate that we are ready to present the rendered frame to the VR display
  vrDisplay.submitFrame();
}

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

Specifications

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

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support No support[1] (Yes) 55 (55)[2] No support No support No support
Feature Android Edge Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile Chrome for Android Samsung Internet for GearVR
Basic support No support No support 55.0 (55) No support No support No support (Yes)[3] (Yes)
 

[1] API Available on all platforms behind a flag, but currently only works on desktop in an experimental version of Chrome (other builds won't return any devices when Navigator.getVRDisplays() is invoked).

[2] Currently only Windows support is enabled by default. Mac support is available in Firefox Nightly.

[3] Currently supported only by Google Daydream.

See also

Document Tags and Contributors

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