StickerGesturesCtrl.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using DigitalRubyShared;
using UnityEngine;
using UnityEngine.EventSystems;
using TouchPhase = DigitalRubyShared.TouchPhase;


public class VectorPair
{
	public Vector2 Current;
	public Vector2 Previous;

	public Vector2 Delta
	{
		get { return Current - Previous; }
	}
}
public class StickerGesturesCtrl : MonoBehaviour
{
	public Action<GameObject, VectorPair> OnStickerPan;
	public Action<GameObject, VectorPair, VectorPair> OnStickerPinch;//<figer1, finger2> (each has current and rprevious)
	public Action OnAllGesturesDone;
	
	private int _stickerLayer;
	private PanGestureRecognizer _panGesture;
	private Camera _camera;
	void Awake ()
	{
		_camera = Camera.main;		
		_stickerLayer = 1 << this.gameObject.layer;
		_panGesture = new PanGestureRecognizer { MinimumNumberOfTouchesToTrack = 1, MaximumNumberOfTouchesToTrack = 5, ThresholdUnits = 0.0f };		
	}

	private void OnEnable()
	{
		FingersScript.Instance.AddGesture(_panGesture);
		_panGesture.StateUpdated += OnPanStateUpdated;
	}

	private void OnDisable()
	{
		_panGesture.StateUpdated -= OnPanStateUpdated;
		FingersScript.Instance.RemoveGesture(_panGesture);
	}

	private void OnPanStateUpdated(GestureRecognizer gesture)
	{
		switch (gesture.State)
		{
			case GestureRecognizerState.Began:
			case GestureRecognizerState.Executing:
			case GestureRecognizerState.Ended:
				UpdateDragStates();
				break;
		}
	}

	
	Dictionary<int, StickerInfo> _stickerInfoByTouchId= new Dictionary<int, StickerInfo>();
	Dictionary<GameObject, StickerInfo> _stickerInfoByGO = new Dictionary<GameObject, StickerInfo>();
	
	private void UpdateDragStates()
	{
		// collect objects by finger id
		foreach (GestureTouch touch in _panGesture.CurrentTrackedTouches)
		{
			if (_stickerInfoByTouchId.ContainsKey(touch.Id))
			{
				// already have one - do nothing?
			}
			else
			{
				// find gameobject
				GameObject stickerGO = GetGOForTouch(touch);				
				if (stickerGO != null)
				{
					StickerInfo stickerInfo;
					if (_stickerInfoByGO.ContainsKey(stickerGO))
					{
						stickerInfo = _stickerInfoByGO[stickerGO];
						if (!stickerInfo.TouchID.Contains(touch.Id))
						{	
							stickerInfo.TouchID.Add(touch.Id);
						}
					}
					else
					{
						stickerInfo = new StickerInfo()
						{
							Sticker = stickerGO,
							TouchID = new List<int>() {touch.Id}
						};
						_stickerInfoByGO.Add(stickerGO, stickerInfo);
					}
					_stickerInfoByTouchId.Add(touch.Id, stickerInfo);						
				}
				else
				{
					// didn't WheelHit any sticker here
				}				
			}
		}

		//iterate over all fingers and report movement
		foreach (StickerInfo stickerInfo in _stickerInfoByGO.Values)
		{			
			GestureTouch gt = GetTouchById(stickerInfo.TouchID[0]);
			if (stickerInfo.TouchID.Count == 1)
			{
				if (gt.TouchPhase == TouchPhase.Moved)
				{					
					OnStickerPan.Invoke(stickerInfo.Sticker,
						new VectorPair()
						{
							Current = _camera.ScreenToWorldPoint(gt.ScreenPosition),
							Previous = _camera.ScreenToWorldPoint(gt.PreviousPosition)
						});
				}
			}
			else
			{
				GestureTouch gt2 = GetTouchById(stickerInfo.TouchID[1]);
				if (gt.TouchPhase == TouchPhase.Moved || gt2.TouchPhase == TouchPhase.Moved)
				{					
					OnStickerPinch.Invoke(stickerInfo.Sticker,
						new VectorPair()
						{
							Current = _camera.ScreenToWorldPoint(gt.ScreenPosition),
							Previous = _camera.ScreenToWorldPoint(gt.PreviousPosition)
						},
						new VectorPair()
						{
							Current = _camera.ScreenToWorldPoint(gt2.ScreenPosition),
							Previous = _camera.ScreenToWorldPoint(gt2.PreviousPosition)
						});
				}
			}
		}
		
		if (_panGesture.State == GestureRecognizerState.Ended)
		{
			_stickerInfoByGO.Clear();
			_stickerInfoByTouchId.Clear();
			
			OnAllGesturesDone.Invoke();
		}
				
	}

	
	GestureTouch GetTouchById(int id)
	{
		return _panGesture.CurrentTrackedTouches.First(touch => touch.Id == id);
	}
	
	GameObject GetGOForTouch(GestureTouch touch)
	{
		int nativeTouchId = touch.Id;
//		if (EventSystem.current.IsPointerOverGameObject(nativeTouchId))
//		{
//			return null;
//		}
		
		var inputModule =  EventSystem.current.currentInputModule;
		MethodInfo methodInfo = inputModule.GetType().GetMethod("GetLastPointerEventData", BindingFlags.Instance | BindingFlags.NonPublic);
		PointerEventData pointerEventData =
			(PointerEventData) methodInfo.Invoke(inputModule, new object[] {nativeTouchId});		
		if (pointerEventData != null && pointerEventData.pointerDrag != null && pointerEventData.pointerDrag.layer != this.gameObject.layer)
		{			
			return null;			
		}
		 		
		var ray = _camera.ScreenPointToRay(touch.ScreenPosition);
		var intersection = Physics2D.GetRayIntersection(ray, 1000, _stickerLayer);
		return intersection != null && intersection.collider != null ? intersection.transform.gameObject : null;
	}

	
	

	private class StickerInfo
	{
		public GameObject Sticker;
		public List<int> TouchID;
	}
}