A simple swipe detector for touchscreens for Unity3D. Four cardinal directions.

SwipeInput.cs

using UnityEngine;

public class SwipeInput : MonoBehaviour {

	public const float MAX_SWIPE_TIME = 1f; 
	
	public const float MIN_SWIPE_DISTANCE = 0.17f;

	public static bool swipedRight = false;
	public static bool swipedLeft = false;
	public static bool swipedUp = false;
	public static bool swipedDown = false;
	public static bool justTouch = false;
	
	
	public bool debugWithArrowKeys = true;

	Vector2 startPos;
	float startTime;

	public void Update()
	{
		swipedRight = false;
		swipedLeft = false;
		swipedUp = false;
		swipedDown = false;
		justTouch = false;

		if (Input.touches.Length > 0)
		{
			Touch t = Input.GetTouch(0);
			if(t.phase == TouchPhase.Began)
			{
				startPos = new Vector2(t.position.x/(float)Screen.width, t.position.y/(float)Screen.width);
				startTime = Time.time;
			}
			if(t.phase == TouchPhase.Ended)
			{
				if (Time.time - startTime > MAX_SWIPE_TIME) // press too long
					return;

				Vector2 endPos = new Vector2(t.position.x/(float)Screen.width, t.position.y/(float)Screen.width);

				Vector2 swipe = new Vector2(endPos.x - startPos.x, endPos.y - startPos.y);

				// Too short swipe, touch
				if (swipe.magnitude < MIN_SWIPE_DISTANCE)
				{
					justTouch = true;
					return;
				}

				if (Mathf.Abs (swipe.x) > Mathf.Abs (swipe.y)) { // Horizontal swipe
					if (swipe.x > 0) {
						swipedRight = true;
					}
					else {
						swipedLeft = true;
					}
				}
				else { // Vertical swipe
					if (swipe.y > 0) {
						swipedUp = true;
					}
					else {
						swipedDown = true;
					}
				}
			}
		}

		if (debugWithArrowKeys) {
			swipedDown = swipedDown || Input.GetKeyDown("down");
			swipedUp = swipedUp || Input.GetKeyDown("up");
			swipedRight = swipedRight || Input.GetKeyDown("right");
			swipedLeft = swipedLeft || Input.GetKeyDown("left");
            		justTouch = justTouch || Input.GetKeyDown("space"); 
		}
	}
}

Touch added.