XRSession.onsqueeze

The XRSession interface's onsqueeze event handler property can be set to a function which is then invoked to handle the squeeze event that's sent when the user successfully completes a primary squeeze action on a WebXR input device. These actions represent the user squeezing or gripping an object or controller.

To learn more about how to use and handle WebXR controller inputs, see Inputs and input sources.

A function to be invoked whenever the XRSession receives a squeeze event.

This snippet of code adds a simple handler for the squeeze event, which responds only to events on the user's off-hand (that is, the hand that isn't their dominant hand). This is determined by comparing the input source's handedness against the value of a handedness property on a user object we've established previously.

xrSession.onsqueeze = event => {
  if (event.inputSource.handedness != user.handedness) {
    handleOffhandSqueeze(event.inputSource, event.frame);
  }
};

This example exapnds somewhat on the previous example by demonstrating a way to implement the ability for the user to drop an object that was previously picked up by the user.. This is just a snippet of code, but should establish the general idea.

After checking that the event occurred on the user's dominant hand, the pose's target ray is obtained. Then we pass the currently held object and the target ray's transform matrix into a function we call dropObjectUsingRay() to drop the object, using the target ray to determine the surface upon which the object should be placed. This also clears the value of heldObject so we know that there's no longer an object in hand.

xrSession.onsqueeze = event => {
  if (event.inputSource.handedness == user.handedness) {
    let targetRayPose = event.frame.getPose(event.inputSource.targetRaySpace, myRefSpace);

    if (user.heldObject && targetRayPose) {
      dropObjectUsingRay(user.heldObject, targetRayPose.transform.matrix):
    }
  }
};

See the examples in the onsqueezestart and onsqueezeend event handlers for the reset of the event handling related to this approach.

• Inputs and input sources
• The other onsqueeze* handlers: onsqueezestart and onsqueezeend
• The squeeze, squeezestart, and squeezeend events