Detect hand swipe gesture in Unity using Kinect with OpenNI

Question

I have a 3D model in my Unity project and I have a JavaScript that rotates the camera based on keyboard arrow keys (left/right).

Now, I need to have a script that detects a horizontal swipe hand gesture and returns a vector that I would use to rotate the camera.

I am using the ZigFu SDK with PrimeSense OpenNI/NITE. The ZigFu SDK comes with sample scripts, one of which is SwipeDetector - I am wondering how does it work?

My setup: I have 3 GameObjects: a 3D model, a MainCamera, and a Directional Light.

So, how do I use the SwipeDetector script in my project? The way I do it right now is 1)Create an empty game object "SwipeDetection", 2) "drag and drop" the SwipeDetector script from ZigFu. I've put in logs in the SwipeDetector script, but I don't see them.

Answer 1

The Zigfu bindings (I'm assuming you're using version 1.4?) dont have a SwipeDetector sample, but they do include a SwipeDetector MonoBehaviour. The SwipeDetector detects vertical and horizontal swipes, but unfortunately doesn't detect the velocity of the swipe.

You have a few options:

1. Use the provided Swipe Detector, and rotate the camera by a fixed amount every time you detect a horizontal swipe (SwipeDetector_Left or SwipeDetector_Right events)

2. Use the provided Swipe Detector, start rotating on Swipe, and stop rotating on the SwipeDetector_Release event. This would be similar to pressing on the arrow keys (assuming you have the same behaviour on keydown/keyup events)

3. Keep track of the hand velocity, and check its value when the swipe occurs. Use this value to rotate the camera. You can keep track of velocity by creating a new MonoBehaviour, and implementing Hand_Create, Hand_Update, and Hand_Destroy (look at any of the scripts in the HandpointControls folder). Keep a queue with the hand points from the last n frames. The delta between the newest & oldest points will be your velocity for those n frames (I recommend you start with 15 frames, or about half a second)

(This will be included in a future Zigfu release :))

Your game object setup sounds right - if you dont see any logs you may not be performing the 'focus gesture' correctly. Try waving or performing a tap towards the sensor - this should cause the Hand_Create event to be called. Once you have a valid handpoint you should get the proper events from the Swipe Detector.

Also worth mentioning your swipe detection game object should have a HandPointControl component (added implicitly with RequireComponent) and that 'ActiveOnStart' should be true.