gistfile1.txt

using UnityEngine;
using System.Collections.Generic;

public class HandGrab : MonoBehaviour
{
    SteamVR_TrackedObject trackedObj;
    SteamVR_Controller.Device controller { get { return SteamVR_Controller.Input((int)trackedObj.index); } }
    GameObject pickUp;
    ConfigurableJoint joint, joint2;
    public TextMesh describe;

    void Start()
    {
        trackedObj = GetComponent<SteamVR_TrackedObject>();
        pickUp = null;
    }

    Transform GetRoot(GameObject o)
    {
        var t = o.transform;
        while (t.parent != null)
            t = t.parent;
        return t;
    }

    void OnTriggerEnter(Collider collider)
    {
        // don't consider anything that's in our hierarchy. we don't want the hands
        // to collide with themselves, with each other, with the body, etc...
        // DONT do this using collision layers - we don't know how many players there will be.
        if (GetRoot(collider.gameObject) == GetRoot(gameObject))
            return;

        // don't consider things that are not rigid bodies. we /might/ be able to fix this in future
        // to use layers.
        if (collider.gameObject.GetComponent<Rigidbody>() == null)
            return;

        pickUp = collider.gameObject;
    }

    void OnTriggerExit(Collider collider)
    {
        if (pickUp == collider.gameObject)
            pickUp = null;
    }

    void ConfigureJoint(float mass, bool driveRotation, ConfigurableJoint j)
    {
        var springFactor = 3000f;
        var damperFactor = 10f;
        var maxForceFactor = 70f;
        var breakFactor = 150f;

        JointDrive drive = j.xDrive;
        drive.positionSpring = springFactor * mass;
        drive.positionDamper = damperFactor * mass;
        drive.maximumForce = maxForceFactor * mass;
        j.xDrive = drive;

        drive = j.yDrive;
        drive.positionSpring = springFactor * mass;
        drive.positionDamper = damperFactor * mass;
        drive.maximumForce = maxForceFactor * mass;
        j.yDrive = drive;

        drive = j.zDrive;
        drive.positionSpring = springFactor * mass;
        drive.positionDamper = damperFactor * mass;
        drive.maximumForce = maxForceFactor * mass;
        j.zDrive = drive;

        if (driveRotation)
        {
            var angularSpringFactor = 30f;
            var angularDamperFactor = 1f;

            j.rotationDriveMode = RotationDriveMode.XYAndZ;
            drive = j.angularYZDrive;
            drive.positionSpring = angularSpringFactor * mass;
            drive.positionDamper = angularDamperFactor * mass;
            j.angularYZDrive = drive;

            drive = j.angularXDrive;
            drive.positionSpring = angularSpringFactor * mass;
            drive.positionDamper = angularDamperFactor * mass;
            j.angularXDrive = drive;
        }

        j.breakForce = breakFactor * mass;
    }

    Vector3 grabPoint;
    Quaternion grabOrientation;

    void Update()
    {
        if (controller.GetPressDown(Valve.VR.EVRButtonId.k_EButton_Grip) && pickUp != null)
        {
            var rb = pickUp.GetComponent<Rigidbody>();
            if (rb.isKinematic)
            {
                // this constraint will allow us to pull/push ourselves through the space.
                var rootGameObject = GetRoot(gameObject).gameObject;

                if (joint2 == null)
                    joint2 = rootGameObject.AddComponent<ConfigurableJoint>();
                joint2.connectedBody = null;
                joint2.anchor = transform.localPosition;
                grabPoint = transform.localPosition;
                grabOrientation = transform.localRotation;
                joint2.connectedAnchor = new Vector3(0, 0, 0);
                joint2.autoConfigureConnectedAnchor = false;
                joint2.configuredInWorldSpace = false;
                ConfigureJoint(rootGameObject.GetComponent<Rigidbody>().mass, true, joint2);
            }
            else
            {
                // this constraint will allow us to hold a free object.
                if (joint == null)
                    joint = gameObject.AddComponent<ConfigurableJoint>();

                joint.connectedBody = rb;
                ConfigureJoint(rb.mass, true, joint);
            }
        }

        if (joint2 != null)
        {
            joint2.targetPosition = transform.localPosition - grabPoint;
            joint2.targetRotation = transform.localRotation * Quaternion.Inverse(grabOrientation);
        }

        if (controller.GetPressUp(Valve.VR.EVRButtonId.k_EButton_Grip))
        {
            if (joint != null)
            {
                Destroy(joint);
                joint = null;
            }

            if (joint2 != null)
            {
                Destroy(joint2);
                joint2 = null;
            }
        }
    }
}