PositionSensorVRDevice

Instance 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 a VRPose object. This is the method you'd normally want to use, versus getImmediateState().

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.

Instance properties

This interface doesn't define any properties of its own, but it does inherit the properties of its parent interface, VRDisplay.

VRDisplay.displayId 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.

VRDisplay.displayName Read only

A human-readable name to identify the VRDevice.

Examples

The following example uses the WebVR API to update the view of a simple 2D canvas scene on each frame of a requestAnimationFrame loop.

function setView() {
  const 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;
    zPos = -posState.position.z > 0.01 ? -posState.position.z : 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 VRPose 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 VRPose.position and VRPose.orientation (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.

Browser compatibility

See also

• WebVR API