VRDisplay.getFrameData()

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 getFrameData() method of the VRDisplay interface accepts a VRFrameData object and populates it with the information required to render the current frame.

This includes the VRPose and view and projection matricies for the current frame.

Syntax

vrDisplayInstance.getFrameData(frameData);

Parameters

frameData
The VRFrameData object you want to populate.

Return value

A Boolean — a value of true is returned if the VRFrameData object was successfully populated, or false if it wasn't.

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
  // curFramePose is a VRPose object
  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 'getEyeParameters()' in that specification.
Editor's Draft Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic Support (Yes)1 2 (Yes)553 No ? ?
FeatureAndroidChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic Support No (Yes)4 ? ? No ? ?

1. Only works on desktop in an experimental version of Chrome (other builds won't return any devices when Navigator.getVRDisplays() is invoked).

2. , this feature is behind the WebVR preference. To change preferences in Chrome, visit chrome://flags.

3. Currently only Windows support is enabled by default. Mac support is available in Firefox Nightly.

4. Currently supported only by Google Daydream.

See also

Document Tags and Contributors

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