Question How to map touch point to the 3D unity space

Hi all,

I need to map the touch point to the unity world space to understand the relative position change.
Here I want to use Camera.ScreenToWorldPoint to map the touch point to world space in Unity.
The code below is used to simulate the screen touch using mouse position.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class TestScreenPointToRayTest : MonoBehaviour
6. {
7.     Camera cam;
8.     public GameObject cube;
9.     public Vector2 MousePos = new Vector3(0, 0);
10.     Vector3 touchWorldPoint;
11.     // Start is called before the first frame update
12.     void Start()
13.     {
14.         cam = Camera.main;
15.     }
16.  
17.     // Update is called once per frame
18.     void Update()
19.     {
20.         MousePos = Input.mousePosition;
21.         Ray ray = cam.ScreenPointToRay(MousePos);
22.         //ray through camera
23.         Debug.DrawRay(ray.origin,ray.direction * 1000, Color.yellow);
24.         //camera to cube
25.         //Debug.DrawRay(cam.gameObject.transform.position,cube.transform.position);
26.         touchWorldPoint = cam.ScreenToWorldPoint(MousePos);
27.         //touch world point to cube
28.         Debug.DrawRay(touchWorldPoint, cube.transform.position);
29.         if (touchWorldPoint == cam.ScreenToWorldPoint(MousePos + new Vector2(10, 10))) {
30.             Debug.Log("ScreenToWorldPoint is wrong");
31.         }
32.         if (touchWorldPoint == cam.transform.position) {
33.             Debug.Log("Touch to world point simply returns the camera position");
34.         }
35.  
36.  
37.  
38.     }
39. }

With the 2 Debug logs I want to test whether the ScreenToWorldPoint actually returns a position based on the touch position. However, the 2 debug log shows all the time. I am kind of confused. Can anyone help me regarding that problem?

Best
ZaoTX

 

I found the problem. It is important to add cam.nearClipPlane to the input of ScreenToWorldPoint