PositionSensorVRDevice: getState() method

{{deprecated_header}}{{APIRef("WebVR API")}}{{Non-standard_header}}

The getState() method of the {{domxref("PositionSensorVRDevice")}} interface returns the current state of the position sensor for the current frame (e.g., within the current {{domxref("window.requestAnimationFrame")}} callback) or for the previous frame, contained with a {{domxref("VRPose")}} object. This is the method you'd normally want to use, vs. {{domxref("PositionSensorVRDevice.getImmediateState")}}.

Syntax

getState()

Parameters

None.

Return value

A {{domxref("VRPose")}} object.

Examples

The following example uses the WebVR API to update the view of a simple {{domxref("CanvasRenderingContext2D")}} scene on each frame of a {{domxref("window.requestAnimationFrame()","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 {{domxref("VRPose")}} object using getState() and storing it in posState. We then check to make sure that position and orientation info is present in the current frame using {{domxref("VRPose.position")}} and {{domxref("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

{{Compat}}

See also

• WebVR API