Unityでダブルタップやトリプルタップを直接取れないプラットフォームでダブルタップを扱う何か。

WrappedInput.cs

using UnityEngine;
using System.Collections.Generic;
using System.Linq;

/// <summary>
/// Touchのラッパー的なクラス。
/// </summary>
public struct WrappedTouch
{
    public Touch original { get; private set; }

    public int tapCount { get; private set; }

    public Vector2 deltaPosition { get; private set; }

    public float deltaTime { get; private set; }

    public int fingerId  { get; private set; }

    public TouchPhase phase { get; private set; }

    public Vector2 position { get; private set; }

    public WrappedTouch(Touch touch, int tapCount = 0)
    {
        this.tapCount = tapCount;
        original = touch;
        deltaPosition = original.deltaPosition;
        deltaTime = original.deltaTime;
        fingerId = original.fingerId;
        phase = original.phase;
        position = original.position;
    }

    public WrappedTouch(WrappedTouch wt, int tapCount = 0)
    {
        this.tapCount = tapCount;
        original = wt.original;
        deltaPosition = wt.deltaPosition;
        deltaTime = wt.deltaTime;
        fingerId = wt.fingerId;
        phase = wt.phase;
        position = wt.position;
    }

    public WrappedTouch(Vector2 dp, float dt, int id, TouchPhase ph, Vector2 p)
    {
        deltaPosition = dp;
        deltaTime = dt;
        fingerId = id;
        phase = ph;
        position = p;
    }
}

/// <summary>
/// 複数回タップを考慮したInput。マウスもTouchに含める。
/// ExecutionOrderをマイナスにすること。
/// </summary>
public class WrappedInput : MonoBehaviour
{
    const int mouseFingerId = int.MinValue;
    Vector2 lastMouse;
    float lastTime;

    [SerializeField] float multiTapIntervalMax = 0.3f;
    [SerializeField] float multiTapInchMax = 0.2f;
    [SerializeField] int multiTapCountMax = 3;
    [SerializeField] bool simulateTouchWithMouse = true;

    WrappedTouch[] m_touches = new WrappedTouch[0];
    List<WrappedTouch> tempTouches = new List<WrappedTouch>();
    List<QueuedTouch> touchQueue = new List<QueuedTouch>();
    List<QueuedTouch> freeTouches = new List<QueuedTouch>();

#if DEBUG_WRAPPED_INPUT
    [SerializeField] List<string> queue;
    [SerializeField] List<string> free;
#endif

    class QueuedTouch
    {
        public int count;
        public float time;
        public WrappedTouch touch;
        public bool free;
        public bool remove;

        public QueuedTouch(WrappedTouch touch)
        {
            this.time = Time.realtimeSinceStartup;
            this.touch = touch;
            this.count = 1;
        }

        public void ApplyNext(WrappedTouch touch)
        {
            this.time = Time.realtimeSinceStartup;
            this.touch = touch;
            this.count ++;
        }
    }

    /// <summary>
    /// シングルトン
    /// </summary>
    static WrappedInput instance;
    public static WrappedInput Instance
    {
        get
        {
            if (!instance)
            {
                instance = FindObjectOfType<WrappedInput>();
                if (!instance)
                {
                    var go = new GameObject("WrappedInput");
                    instance = go.AddComponent<WrappedInput>();
                }
            }
            return instance;
        }
    }

    void Awake()
    {
        instance = this;
        Input.simulateMouseWithTouches = !simulateTouchWithMouse;
    }

    public static WrappedTouch[] touches
    {
        get
        {
            return Instance.m_touches;
        }
    }

    void Update()
    {
        var multiTapDistMax = multiTapInchMax * Screen.dpi;
        tempTouches.Clear();
        var touches = Input.touches;

        // マウスをタップに加える
        WrappedTouch mouse = new WrappedTouch();
        int loop = touches.Length;
        if (!Input.simulateMouseWithTouches)
        {
            loop++;
            var dt = Time.realtimeSinceStartup - lastTime;
            var dp = (Vector2)Input.mousePosition - lastMouse;
            if (Input.GetMouseButtonDown(0))
                mouse = new WrappedTouch(dp, dt, mouseFingerId, TouchPhase.Began, Input.mousePosition);
            else if (Input.GetMouseButtonUp(0))
                mouse = new WrappedTouch(dp, dt, mouseFingerId, TouchPhase.Ended, Input.mousePosition);
            else if (Input.GetMouseButton(0))
                mouse = new WrappedTouch(dp, dt, mouseFingerId, TouchPhase.Moved, Input.mousePosition);
            else
                loop--;
            lastMouse = Input.mousePosition;
            lastTime = Time.realtimeSinceStartup;
        }

        for (int i = 0; i < loop; i ++)
        {
            var currentTouch = i == touches.Length ? mouse : new WrappedTouch(touches[i]);

            // 既に数える必要が無いタップ
            var iFree = freeTouches.FindIndex(x => x.touch.fingerId == currentTouch.fingerId);
            if (iFree >= 0) {
                if (currentTouch.phase == TouchPhase.Canceled
                    || currentTouch.phase == TouchPhase.Ended) {
                    freeTouches[iFree].remove = true;
                }
                tempTouches.Add(new WrappedTouch(currentTouch, freeTouches[iFree].count));
                continue;
            }

            // キューに同じIDのタッチがある場合（これはおまけ）
            var qSame = touchQueue.FindIndex(x => x.touch.phase == TouchPhase.Began && x.touch.fingerId == currentTouch.fingerId);
            if (qSame >= 0)
            {
                // キューにあるけど、範囲外
                if (Vector2.Distance(touchQueue[qSame].touch.position, currentTouch.position) > multiTapDistMax
                    || Time.realtimeSinceStartup - touchQueue[qSame].time > multiTapIntervalMax)
                {
                    // 現在のカウントで流す
                    for (int j = 0; j < touchQueue.Count; j ++)
                    {
                        if (touchQueue[j].touch.fingerId == currentTouch.fingerId)
                        {
                            tempTouches.Add(new WrappedTouch(touchQueue[j].touch, touchQueue[qSame].count));
                            touchQueue[j].remove = j != qSame;
                        }
                    }
                    touchQueue[qSame].free = true;
                    touchQueue.Add(new QueuedTouch(currentTouch));
                }
                // キューにあってタップカウントが増える
                else if (currentTouch.phase == TouchPhase.Began)
                {
                    // カウント0で流す
                    for (int j = 0; j < touchQueue.Count; j ++)
                    {
                        if (touchQueue[j].touch.fingerId == currentTouch.fingerId)
                        {
                            tempTouches.Add(new WrappedTouch(touchQueue[j].touch, 0));
                            touchQueue[j].remove = j != qSame;
                        }
                    }
                    touchQueue[qSame].ApplyNext(currentTouch);
                }
                // キューにあるのでキューに詰める
                else
                {
                    touchQueue.Add(new QueuedTouch(currentTouch));
                }
                continue;
            }

            // キューに近い位置のタップがある場合
            var qNear = touchQueue.FindIndex(
                x => x.touch.phase == TouchPhase.Began
                && Vector2.Distance(x.touch.position, currentTouch.position) < multiTapDistMax
                && Time.realtimeSinceStartup - x.time <= multiTapIntervalMax);
            if (qNear >= 0)
            {
                // カウント0で流す
                for (int j = 0; j < touchQueue.Count; j ++)
                {
                    if (touchQueue[j].touch.fingerId == touchQueue[qNear].touch.fingerId)
                    {
                        tempTouches.Add(new WrappedTouch(touchQueue[j].touch, 0));
                        touchQueue[j].remove = j != qNear;
                    }
                }
                touchQueue[qNear].ApplyNext(currentTouch);
            }
            else if (currentTouch.phase == TouchPhase.Began)
            {
                touchQueue.Add(new QueuedTouch(currentTouch));
            }
            // 開始が記録されてないタッチが検出...されることはないはず
            else
            {
                Debug.Log("Unexpected touch: " + currentTouch);
            }
        }

        // 時間切れタップ判定
        for (int i = 0; i < touchQueue.Count; i ++)
        {
            if (!touchQueue[i].free && !touchQueue[i].remove && touchQueue[i].touch.phase == TouchPhase.Began
                && Time.realtimeSinceStartup - touchQueue[i].time > multiTapIntervalMax)
            {
                var ended = touchQueue.FindIndex(x => x.touch.fingerId == touchQueue[i].touch.fingerId
                    && (x.touch.phase == TouchPhase.Ended || x.touch.phase == TouchPhase.Canceled)) >= 0;
                for (int j = 0; j < touchQueue.Count; j ++)
                {
                    if (touchQueue[j].touch.fingerId == touchQueue[i].touch.fingerId)
                    {
                        tempTouches.Add(new WrappedTouch(touchQueue[j].touch, touchQueue[i].count));
                        touchQueue[j].free =  i == j && !ended;
                        touchQueue[j].remove = i != j || ended;
                    }
                }
            }
        }
        // removeフラッグで消去、freeフラッグでfreeTouchesに移動
        freeTouches.RemoveAll(x => x.remove);
        for (int i = 0; i < touchQueue.Count; i ++)
        {
            if (touchQueue[i].free) {
                freeTouches.Add(touchQueue[i]);
            }
        }
        touchQueue.RemoveAll(x => x.remove || x.free);
        for (int i = 0; i < freeTouches.Count; i ++)
        {
            freeTouches[i].remove = false;
        }

        // コピー
        System.Array.Resize(ref m_touches, tempTouches.Count);
        tempTouches.CopyTo(m_touches);

#if DEBUG_WRAPPED_INPUT
        free = freeTouches.Select(x => x.touch.fingerId + ":" + x.touch.tapCount).ToList();
        queue = touchQueue.Select(x => x.touch.fingerId + ":" + x.touch.tapCount).ToList();
#endif
    }
}