How to limit the rotation of an object (248308)

Archived Forums Questions & Answers
1

I have a code that allows me to rotate my tank tower and its barrel using UI Joystick. The controls part is working, the problem is that I can’t limit the rotation of my barrel (I need to lock it on 15 degrees). I’ve tried literally everything that my newbie hands can, but nothing works.

The closest I could get to my goal is the thing you see in the code (I commented it). It works, kinda. When I start a game, the barrel’s X axis locks on -15 degrees and when I try to rotate the barrel up, as it reaches 0 degrees it changes to -15 degrees back. Please help!

185889-2021-09-06-222119.png
185889-2021-09-06-222119.png713×358 166 KB

using UnityEngine;

public class TurretJoystick : MonoBehaviour
{
    public float rotationYSpeed = 35f;
    public float rotationXSpeed = 35f;
    public VariableJoystick gunJoystick;
    
    public GameObject Gun; //tank barrel

    void Update()
    {
        //rotate turret (everything works because i don't need to lock the rotation)
        float turretRotation = gunJoystick.Horizontal * rotationYSpeed;
        turretRotation *= Time.deltaTime;
        transform.Rotate(0f, turretRotation, 0f);

        //rotate gun
        float gunRotation = gunJoystick.Vertical * rotationXSpeed;
        gunRotation *= Time.deltaTime;
        Gun.transform.Rotate(gunRotation, 0f, 0f);

        //this is the part where i tried to lock the rotation
        float minRotation = -15;
        float maxRotation = 15;
        Vector3 currentRotation = Gun.transform.localRotation.eulerAngles;
        currentRotation.x = Mathf.Clamp(currentRotation.x, minRotation, maxRotation);
        Gun.transform.localRotation = Quaternion.Euler(currentRotation);    
    }
}
3

The problem with BobyStar’s solutioni is that he keeps reacquiring euler angles from the rotation. This will cause the angles to ‘snap around’ sometimes. For example, the same rotation can be described by many different values. -90 degrees is the same rotation as 270 degrees. This messes with your clamping.
Instead, try to keep the euler angles in a local variable (Vector3 currentRotation in your case), and don’t set it from Gun.transform. That way, your gun rotation will always be represented by eulerAngles, so no ‘snapping around’ happens (since they are just floats in a vector).

2

Instead of rotating the transform, you should change currentRotation.x by the gunRotation then limit the rotation. Lastly set the transform’s local rotation to the new currentRotation:

 // rotates currentRotation
 Vector3 currentRotation = Gun.transform.localEulerAngles; // get local euler angles
 float gunRotation = gunJoystick.Vertical * rotationXSpeed;
 gunRotation *= Time.deltaTime;
 currentRotation.x += gunRotation; // adds gunRotation to the x axis of the currentRotation

 // limits currentRotation.x and applies it to the transform
 float minRotation = -15;
 float maxRotation = 15;
 currentRotation.x = Mathf.Clamp(currentRotation.x, minRotation, maxRotation);
 Gun.transform.localEulerAngles = currentRotation; // you can just use transform.localEulerAngles
4

This may help someone, for the issue of resetting back to 15

// rotates currentRotation
  Vector3 currentRotation = Gun.transform.localEulerAngles; // get local euler angles
  float gunRotation = gunJoystick.Vertical * rotationXSpeed;
  gunRotation *= Time.deltaTime;
 if(currentRotation.x > 180) { currentRotation.x -= 360; } // added
  currentRotation.x += gunRotation; // adds gunRotation to the x axis of the currentRotation
  // limits currentRotation.x and applies it to the transform
  float minRotation = -15;
  float maxRotation = 15;
  currentRotation.x = Mathf.Clamp(currentRotation.x, minRotation, maxRotation);
  Gun.transform.localEulerAngles = currentRotation; // you can just use transform.localEulerAngles