Move object by touch input

Questions & Answers
1

Hi

I’m trying to implement a touch function into my game which lets the player object move to the left or to the right (2D game) depending on the x position the user touches on the screen.

So for example, if the user presses for a long time on the left side of the screen (-x coordinate) the player object moves to the left.

I have the following code in C# but it doesn’t respond to my touches:

using UnityEngine;
using System.Collections;

public class Touch : MonoBehaviour {

	public GameObject player;

	// Use this for initialization
	void Start () {
		
	}
	
	// Update is called once per frame
	void Update () {

		if(Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Stationary)
		{
			Vector2 touchDeltaPosition = Input.GetTouch(0).deltaPosition;

			//Check if it is left or right?
			if(touchDeltaPosition.x < 0.0f){
				player.transform.Translate(Vector3.left * 10 * Time.deltaTime);
			} else if (touchDeltaPosition.x > 0.0f) {
				player.transform.Translate(Vector3.right * 10 * Time.deltaTime);
			}

		}
	}
}

Please note that I’m new to Unity.

Thanks for your help in advance!

2

Delta position is the change in position since the last frame. You want the position of the touch instead.

Your if left/right statements will need to be changed as well since touchPosition will now be in pixels instead of world position.

Replace:

Vector2 touchDeltaPosition = Input.GetTouch(0).deltaPosition;

With:

Vector3 touchPosition = Input.GetTouch(0).position;
3

Just in case someone is wondering how I managed to fix this. I used the following code.
This code is not optimized but it shows you how to get started:

using UnityEngine;
using System.Collections;

public class Touch : MonoBehaviour {

	public GameObject player;

	// Use this for initialization
	void Start () {
		
	}
	
	// Update is called once per frame
	void Update () {

		if(Input.touchCount > 0 && Input.GetTouch(0).phase == TouchPhase.Stationary)
		{
			Vector2 touchPosition = Input.GetTouch(0).position;
			double halfScreen = Screen.width / 2.0;

			//Check if it is left or right?
			if(touchPosition.x < halfScreen){
				player.transform.Translate(Vector3.left * 5 * Time.deltaTime);
			} else if (touchPosition.x > halfScreen) {
				player.transform.Translate(Vector3.right * 5 * Time.deltaTime);
			}

		}

	}
}
4

How would you clamp this so that it cannot go past a certain area or range on the x axis? @monserboy

5

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

public class ObjectTouchMove : MonoBehaviour {

private Vector3 _touchPosition;
private Rigidbody2D _rb;
private Vector3 _direction;
private float _moveSpeed = 10f;

// Use this for initialization
void Start () {
    _rb = GetComponent<Rigidbody2D>();
}

// Update is called once per frame
void Update () {
    if (Input.touchCount > 0)
    {
        Touch touch = Input.GetTouch(0);
        _touchPosition = Camera.main.ScreenToWorldPoint(touch.position);
        _touchPosition.z = 0;
        _direction = (_touchPosition - transform.position);
        _rb.velocity = new Vector2(_direction.x, _direction.y) * _moveSpeed;

        if (touch.phase == TouchPhase.Ended)
        {
            _rb.velocity = Vector2.zero;
        }
    }
}

}