Detecting touch on a specific object in Unity - unity3d

Question

working on an android game in Unity 2D. Long story short, I have two separate objects in the scene which have this script attached on:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class SwipeScript : MonoBehaviour
{
Vector2 startPos, endPos, direction;
float touchTimeStart, touchTimeFinish, timeInterval;
public static int brojbacanja=0;
public static bool bacenaprva = false;
[Range (0.05f, 1f)]
public float throwForce = 0.3f;
void Update(){
if (Input.touchCount > 0 && Input.GetTouch (0).phase == TouchPhase.Began && brojbacanja == 0) {
touchTimeStart = Time.time;
startPos = Input.GetTouch (0).position;
}
if (Input.touchCount > 0 && Input.GetTouch (0).phase == TouchPhase.Ended && brojbacanja == 0) {
touchTimeFinish = Time.time;
timeInterval = touchTimeFinish - touchTimeStart;
endPos = Input.GetTouch (0).position;
direction = startPos - endPos;
GetComponent<Rigidbody2D> ().AddForce (-direction / timeInterval * throwForce);
brojbacanja = 1;
bacenaprva = true;
}
}
}
What this does is pretty much alowing me to swipe anywhere on the screen and throw an object which it's attached to. Since I have two different objects which I would like to throw separately, I want to change it a bit so when I touch object which I want to throw, other one stays still. I read about this problem alredy and tried using Raycast and OnMouseDown() but didn't know how to implement it.
If anyone can help, would be grateful.

Answer 1

Since this script will be on each object in the scene you will need to have an extra variable and a check to see if the initial touch is intersecting your object.
If you are using 3D objects (which I am assuming because you mentioned ray tracing), then you will want something that converts the touch position on the screen to a ray, that you then cast to see if it intersects your object. Your object will have to have collision for this to work.
public class SwipeScript : MonoBehaviour
{
// added these two values, set the coll value to your collider on this object.
bool isTouching;
public Collider coll;
Vector2 startPos, endPos, direction;
float touchTimeStart, touchTimeFinish, timeInterval;
public static int brojbacanja=0;
public static bool bacenaprva = false;
[Range (0.05f, 1f)]
public float throwForce = 0.3f;
void Update(){
if (Input.touchCount > 0 && Input.GetTouch (0).phase == TouchPhase.Began && brojbacanja == 0) {
if(IsTouchOverThisObject(Input.GetTouch(0))) {
isTouching = true;
touchTimeStart = Time.time;
startPos = Input.GetTouch (0).position;
}
}
if (isTouching && Input.touchCount > 0 && Input.GetTouch (0).phase == TouchPhase.Ended && brojbacanja == 0) {
isTouching = false;
touchTimeFinish = Time.time;
timeInterval = touchTimeFinish - touchTimeStart;
endPos = Input.GetTouch (0).position;
direction = startPos - endPos;
GetComponent<Rigidbody2D> ().AddForce (-direction / timeInterval * throwForce);
brojbacanja = 1;
bacenaprva = true;
}
}
bool IsTouchOverThisObject(Touch touch) {
Ray ray = Camera.main.ScreenPointToRay(new Vector3(touch.position.x, touch.position.y, 0));
RaycastHit hit;
// you may need to adjust the max distance paramter here based on your
// scene size/scale.
return coll.Raycast(ray, out hit, 1000.0f);
}
}