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This feature is obsolete.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
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 PositionSensorVRDevice
interface of the WebVR API represents VR hardware's position sensor. You can access information such as the current position and orientation of the sensor in relation to the head mounted display through the PositionSensorVRDevice.getState()
method.
Methods
PositionSensorVRDevice.getState()
- Returns the current state of the position sensor for the current frame (e.g. within the current
window.requestAnimationFrame
callback) or for the previous frame, contained with aVRPositionState
object. This is the method you'd normally want to use, versusgetImmediateState()
. PositionSensorVRDevice.getImmediateState()
- 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.
PositionSensorVRDevice.resetSensor()
- Can be used to reset the sensor if desired, returning the position and orientation values to zero.
Properties
This interface doesn't define any properties of its own, but it does inherit the properties of its parent interface, VRDevice
.
VRDevice.hardwareUnitId
Read only- Returns the distinct hardware ID for the overall hardware unit that this
VRDevice
is a part of. All devices that are part of the same physical piece of hardware will have the samehardwareUnitId
. VRDevice.deviceId
Read only- Returns the ID for this specific
VRDevice
. The ID shouldn’t change across browser restarts, allowing configuration data to be saved based on it. VRDevice.deviceName
Read only- A human-readable name to identify the
VRDevice
.
Examples
The following example is taken from our positionsensorvrdevice demo, which uses the WebVR API to update the view of a simple 2D canvas
scene on each frame of a requestAnimationFrame
loop.
function setView() { var posState = gPositionSensor.getState(); 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 PositionSensorVRDevice.getState()
and storing it in posState
. 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 |
---|---|---|
WebVR The definition of 'PositionSensorVRDevice' in that specification. |
Editor's Draft | Initial definition |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | (Yes)[1] | 39 (39)[2] | No support | No support | No support |
Feature | Android | Firefox Mobile (Gecko) | Firefox OS (Gecko) | IE Phone | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|
Basic support | No support | 39.0 (39)[2] 44.0 (44)[3] |
No support | No support | No support | No support | No support |
- [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 thedom.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] The
dom.vr*
prefs are enabled by default at this point, in Nightly/Aurora editions.
See also
- WebVR API homepage.
- MozVr.com — demos, downloads, and other resources from the Mozilla VR team.