ThrowableObject FindNearestObject(ThrowableObject[] objects, Vector3 position)
{
ThrowableObject nearestObject = null;
float lowestDist = Mathf.Infinity;
foreach (var throwable in objects)
{
foreach (var collider in throwable.colliders)
{
float dist = Vector3.Distance(position, collider.ClosestPoint(position));
if (dist < GRAB_RANGE && dist < lowestDist)
{
lowestDist = dist;
nearestObject = throwable;
}
}
}
return(nearestObject);
}
// For each given hand: Grab, Move, or Release a GameObject
void UpdateForHand(XRNode handNode, HandData handData)
{
InputDevice device = InputDevices.GetDeviceAtXRNode(handNode);
bool deviceHasData = device.TryGetFeatureValue(CommonUsages.isTracked, out bool deviceIsTracked);
bool? isGrabbing = TryGetIsGrabbing(device);
bool isDeviceTapped = isGrabbing ?? false;
deviceHasData &= (isGrabbing != null);
deviceHasData &= device.TryGetFeatureValue(CommonUsages.devicePosition, out Vector3 devicePosition);
deviceHasData &= device.TryGetFeatureValue(CommonUsages.deviceRotation, out Quaternion deviceRotation);
if (!deviceHasData || !deviceIsTracked)
{
return;
}
// Update the hand's transform for use below
handData.transform.SetPositionAndRotation(devicePosition, deviceRotation);
// If this hand should grab an object, look for one nearby
if (handData.objectHeld == null && isDeviceTapped && !handData.wasTapped)
{
ThrowableObject nearestObject = FindNearestObject(m_throwableObjects, devicePosition);
if (nearestObject != null)
{
// Grab the object
handData.objectHeld = new ObjectHeldData {
rigidbody = nearestObject.GetComponent <Rigidbody>()
};
handData.objectHeld.rigidbody.isKinematic = true;
// Record the offset from the hand pose to the object origin pose
handData.objectHeld.positionInHandSpace = handData.transform.InverseTransformPoint(handData.objectHeld.rigidbody.position);
handData.objectHeld.rotationInHandSpace = Quaternion.Inverse(deviceRotation) * handData.objectHeld.rigidbody.rotation;
}
}
// If this hand is holding an object, update its pose.
if (handData.objectHeld != null)
{
handData.objectHeld.rigidbody.position = handData.transform.TransformPoint(handData.objectHeld.positionInHandSpace);
handData.objectHeld.rigidbody.rotation = deviceRotation * handData.objectHeld.rotationInHandSpace;
}
// If this hand should release the object, derive the new object velocity using the current hand velocity and relative object pose.
if (handData.objectHeld != null && !isDeviceTapped)
{
// Get the device's velocity and angular velocity
bool hasData = device.TryGetFeatureValue(CommonUsages.deviceVelocity, out Vector3 deviceVelocity);
hasData &= device.TryGetFeatureValue(CommonUsages.deviceAngularVelocity, out Vector3 deviceAngularVelocity);
if (!hasData)
{
deviceVelocity = Vector3.zero;
deviceAngularVelocity = Vector3.zero;
}
// As the object is released, the hand and object share an angular velocity.
handData.objectHeld.rigidbody.angularVelocity = deviceAngularVelocity;
// As the object is released, we apply two velocities - the velocity of the hand relative to the world,
// and the velocity of the object's center of mass relative to the hand.
handData.objectHeld.rigidbody.velocity = deviceVelocity +
Vector3.Cross(handData.objectHeld.rigidbody.angularVelocity, handData.objectHeld.rigidbody.worldCenterOfMass - devicePosition);
handData.objectHeld.rigidbody.isKinematic = false;
handData.objectHeld = null;
}
handData.wasTapped = isDeviceTapped;
}