Assets/Drag.cs(12,66): error CS0121: The call is ambiguous between the following methods or properties: UnityEngine.Vector3.operator -(UnityEngine.Vector3, UnityEngine.Vector3)' and UnityEngine.Vector2.operator -(UnityEngine.Vector2, UnityEngine.Vector2)’
using UnityEngine;
using System.Collections;
[RequireComponent(typeof(BoxCollider2D))]
public class Drag : MonoBehaviour {
private Vector3 screenPoint;
private Vector3 offset;
void OnMouseDown() {
offset = gameObject.GetComponent<Rigidbody2D> ().velocity - Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z));
}
void OnMouseDrag()
{
Vector3 curScreenPoint = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z);
Vector3 curPosition = Camera.main.ScreenToWorldPoint(curScreenPoint) + offset;
GetComponent<Rigidbody2D> ().velocity = curPosition;
}
}
RigidBody2D.velocity is a Vector2, and ScreenToWorldPoint returns a Vector3 so you’re subtracting a Vector3 from a Vector2 on line 12 in your sample code. There isn’t a vector subtraction operator overload which allows that, so you get the error.
You can resolve this by typecasting the result of ScreenToWorldPoint to a Vector2.
offset = gameObject.GetComponent<Rigidbody2D> ().velocity -
(Vector2)Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z));
