PositionSensorVRDevice.getImmediateState()

Obsolete
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

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

The getImmediateState() method of the VRDevice interface returns the current instantaneous position sensor state. This is intended to only be used rarely, for certain special uses, for example sampling the immediate position of a hand orientation sensor — or at least it will be, in the future.

For most standard uses, you'll probably want to use PositionSensorVRDevice.getState instead.

Syntax

var myPositionstate = PositionSensorVRDevice.getImmediateState();

Parameters

None.

Returns

A VRPositionState object.

Examples

Our positionsensorvrdevice demo uses the WebVR API to update the view of a simple 2D canvas scene on each frame of a requestAnimationFrame loop. The main function that updates the view data is as follows:

function setView() {
  var posState = gPositionSensor.getImmediateState();
  if(posState.hasPosition) {
    posPara.textContent = 'Position: x' + roundToTwo(posState.position.x) + " y"
                                + roundToTwo(posState.position.y) + " z"
                                + roundToTwo(posState.position.z);
    xPos = -posState.position.x * WIDTH * 2;
    yPos = posState.position.y * HEIGHT * 2;
    if(-posState.position.z > 0.01) {
      zPos = -posState.position.z;
    } else {
      zPos = 0.01;
    }
  }

  if(posState.hasOrientation) {
    orientPara.textContent = 'Orientation: x' + roundToTwo(posState.orientation.x) + " y"
                                + roundToTwo(posState.orientation.y) + " z"
                                + roundToTwo(posState.orientation.z);
    xOrient = posState.orientation.x * WIDTH;
    yOrient = -posState.orientation.y * HEIGHT * 2;
    zOrient = posState.orientation.z * 180;

  }
}

Here we are grabbing a VRPositionState object using getImmediateState() and storing it in posState (the actual live demo uses getState(), but both seem to do the same thing currently.) We then check to make sure that position and orientation info is present in the current frame using VRPositionState.hasPosition and VRPositionState.hasOrientation (these return null if, for example the head mounted display is turned off or not pointing at the position sensor, which would cause an error.)

We then output the x, y and z position and orientation values for informational purposes, and use those values to update the xPos, yPos, zPos, xOrient, yOrient, and zOrient variables, which are used to update the scene rendering on each frame.

Specifications

Specification Status Comment
Unknown
The definition of 'PositionSensorVRDevice' in that specification.
Unknown Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes1 No392 3 No No No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support No No No

393 4

445

No No No

1. The support in Chrome is currently experimental. To find information on Chrome's WebVR implementation status including supporting builds, check out Bringing VR to Chrome by Brandon Jones.

2. The support for this feature is currently disabled by default in Firefox. To enable WebVR support in Firefox Nightly/Developer Edition, you can go to about:config and enable the dom.vr* prefs. A better option however is to install the WebVR Enabler Add-on, which does this for you and sets up other necessary parts of the environment

3. From version 39: this feature is behind the dom.vr* preference. To change preferences in Firefox, visit about:config.

4. The support for this feature is currently disabled by default in Firefox. To enable WebVR support in Firefox Nightly/Developer Edition, you can go to about:config and enable the dom.vr* prefs. A better option however is to install the WebVR Enabler Add-on, which does this for you and sets up other necessary parts of the environment.

5. The dom.vr* prefs are enabled by default at this point, in Nightly/Aurora editions.

See also

Document Tags and Contributors

Contributors to this page: ExE-Boss, chrisdavidmills, Sebastianz
Last updated by: ExE-Boss,