LeapMotion + Unity: Moving an object in a 3D world based on the angle of a finger

Question

I am trying to create an aiming system in Unity, where index finger is being used to control a crosshair. The game is being played with Oculus and Leap Motion is mounted on to the Oculus headset.

I have tried to calculate the position for the crosshair based on the angle of the index finger and draw a ray based on a given distance. I have also tried calculating the crosshair location just based on the direction of the index finger and given distance like this:

Vector3 targetPoint = direction * direction;

Here is what I have tried:

void Start () {
    crossHair = GameObject.Find("Crosshair Component");
    myCamera = GameObject.Find("CenterEyeAnchor");
    target = crossHair.transform;
    controller = new Controller(); 
    indexFinger = new Finger();

    void Update () {

    crossHair.transform.position = myCamera.transform.position;
    frame = controller.Frame();
    List<Hand> handList = new List<Hand>();
    for (int h = 0; h < frame.Hands.Count; h++)
    {
        Hand leapHand = frame.Hands[h];
        handList.Add(leapHand);
    }

    if (handList != null && frame.Hands.Count > 0) {
        indexFinger = frame.Hands[0].Fingers[(int)Finger.FingerType.TYPE_INDEX];
        if (indexFinger.IsExtended)
        {
            Vector3 fingerTipPos = indexFinger.TipPosition.ToUnityScaled();

            Vector3 originAngle = indexFinger.TipPosition.ToUnityScaled();
            Vector3 targetAngle = crossHair.transform.position;
            float distance = 1; 

            Vector3 direction = indexFinger.Direction.ToUnityScaled();
            Ray rayToTest = new Ray(originAngle, targetAngle);
            Vector3 targetPoint = rayToTest.GetPoint(distance);

            //Problem is here. How should these targetPoint values be used to calculate correct position for the crosshair?
            crossHair.transform.position = new Vector3(crossHair.transform.position.x + (targetPoint.x), y,
                                                    crossHair.transform.position.z + (targetPoint.z));
        }


    }
}

}

With similar calculations as these I have been able to move the crosshair accordingly on horizontal level by modifying x and z values but the y-axis seems to be the biggest problem. Y-axis seems to always receive too low values. The crosshair element is placed as a child element for the CenterEyeAnchor camera object in Unity.

So questions are: Is the way of calculating the target point position right as I have been trying to make it? What kind of calculations would I have to make for the crosshairs position based on the new target point value to make it behave accordingly to the index finger movement? Scaling factors for the values?

i'm very familiar with oculus and familiar with leap, but it's almost impossible to help unless you include some sort of screen shot showing the setup of your objects. it's absolutely impossible to "know where anything is" currently. — Fattie

Sakhas Sakhas · Accepted Answer · 2016-04-18T07:50:49

Pictures of the project setup and current object positions attached.

Here is the image for the setup of objects

Here is the image of the crosshair's false position

LeapMotion + Unity: Moving an object in a 3D world based on the angle of a finger

1 Answers