How to rotate a tank turret and gun?

Question

Hi all. I am trying to build a first person tank game. As you can see in the attached video, I have used a smooth look at action to get the turret and gun to follow where I point my mouse, however, I cannot figure out how to constrain the gun to the vertical axis. Right now it just follows anywhere. I just want the gun to move up and down to where I point the camera. Help?

https://youtu.be/mDPMGGyFF6U

Answer 1

Answer by bpaynom · Jul 09, 2019 at 06:46 PM

In the LateUpdate() callback, set the localRotation of the gun like this.

 public class ClampRotation : MonoBehaviour
 {
     public GameObject gun;
 
     void LateUpdate()
     {
         // if you want to clamp on X-Axis
         gun.transform.localEulerAngles = new Vector3( gun.transform.localEulerAngles.x, 0, 0 );
     }
 }

EDIT: If you want to clamp the the degrees then you can add two extra fields

 [SerializeField] private float minAngle, maxAngle;

 public class ClampRotation : MonoBehaviour
 {
     public GameObject gun;
 
     void LateUpdate()
     {
         float clampedAngle = Mathf.Clamp( gun.transform.localEulerAngles.x, minAngle, maxAngle );
         // if you want to clamp on X-Axis
         gun.transform.localEulerAngles = new Vector3( clampedAngle , 0, 0 );
     }
 }

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Answer 2

@ConcanoPayno thanks, but I've run into a problem. I keep getting this error that the name "gun" does not exist in the current context. Here is the source code for the gun

 using UnityEngine;
 
 namespace HutongGames.PlayMaker.Actions
 {
     [ActionCategory(ActionCategory.Transform)]
     [Tooltip("Smoothly Rotates a Game Object so its forward vector points at a Target. The target can be defined as a Game Object or a world Position. If you specify both, then the position will be used as a local offset from the object's position.")]
     public class SmoothLookAt : FsmStateAction
     {
         [RequiredField]
         [Tooltip("The GameObject to rotate to face a target.")]
         public FsmOwnerDefault gameObject;
         
         [Tooltip("A target GameObject.")]
         public FsmGameObject targetObject;
         
         [Tooltip("A target position. If a Target Object is defined, this is used as a local offset.")]
         public FsmVector3 targetPosition;
 
         [Tooltip("Used to keep the game object generally upright. If left undefined the world y axis is used.")]
         public FsmVector3 upVector;
         
         [Tooltip("Force the game object to remain vertical. Useful for characters.")]
         public FsmBool keepVertical;
         
         [HasFloatSlider(0.5f,15)]
         [Tooltip("How fast the look at moves.")]
         public FsmFloat speed;
         
         [Tooltip("Draw a line in the Scene View to the look at position.")]
         public FsmBool debug;
 
         [Tooltip("If the angle to the target is less than this, send the Finish Event below. Measured in degrees.")]
         public FsmFloat finishTolerance;
 
         [Tooltip("Event to send if the angle to target is less than the Finish Tolerance.")]
         public FsmEvent finishEvent;
 
         private GameObject previousGo; // track game object so we can re-initialize when it changes.
         private Quaternion lastRotation;
         private Quaternion desiredRotation;
 
         public override void Reset()
         {
             gameObject = null;
             targetObject = null;
             targetPosition = new FsmVector3 { UseVariable = true};
             upVector = new FsmVector3 { UseVariable = true};
             keepVertical = true;
             debug = false;
             speed = 5;
             finishTolerance = 1;
             finishEvent = null;
         }
 
         public override void OnPreprocess()
         {
             Fsm.HandleLateUpdate = true;
         }
 
         public override void OnEnter()
         {
             previousGo = null;
         }
 
         void LateUpdate()
         {
             //clamp on X-Axis
             gun.transform.localEulerAngles = new Vector3(gun.transform.localEulerAngles.x, 0, 0);
         }
 
         public override void OnLateUpdate()
         {
             DoSmoothLookAt();
         }
 
         void DoSmoothLookAt()
         {
             var go = Fsm.GetOwnerDefaultTarget(gameObject);
             if (go == null)
             {
                 return;
             }
 
             var goTarget = targetObject.Value;
             if (goTarget == null && targetPosition.IsNone)
             {
                 return;
             }
 
             // re-initialize if game object has changed
             
             if (previousGo != go)
             {
                 lastRotation = go.transform.rotation;
                 desiredRotation = lastRotation;
                 previousGo = go;
             }
             
             // desired look at position
 
             Vector3 lookAtPos;
             if (goTarget != null)
             {
                 lookAtPos = !targetPosition.IsNone ?
                     goTarget.transform.TransformPoint(targetPosition.Value) : 
                     goTarget.transform.position;
             }
             else
             {
                 lookAtPos = targetPosition.Value;
             }
             
             if (keepVertical.Value)
             {
                 lookAtPos.y = go.transform.position.y;
             }
             
             // smooth look at
 
             var diff = lookAtPos - go.transform.position;
             if (diff != Vector3.zero && diff.sqrMagnitude > 0)
             {
                 desiredRotation = Quaternion.LookRotation(diff, upVector.IsNone ? Vector3.up : upVector.Value);
             }
 
             lastRotation = Quaternion.Slerp(lastRotation, desiredRotation, speed.Value * Time.deltaTime);
             go.transform.rotation = lastRotation;
             
             // debug line to target
             
             if (debug.Value)
             {
                 Debug.DrawLine(go.transform.position, lookAtPos, Color.grey);
             }
 
             // send finish event?
 
             if (finishEvent != null)
             {
                 var targetDir = lookAtPos - go.transform.position;
                 var angle = Vector3.Angle(targetDir, go.transform.forward);
 
                 if (Mathf.Abs(angle) <= finishTolerance.Value)
                 {
                     Fsm.Event(finishEvent);
                 }
             }
         }
 
     }
 }

I apologize, but I am very new to scripting. I have been using Unity Playmaker lately and only in the past week have I started working on hand scripting. What am I doing wrong here? thanks for your time.

How to rotate a tank turret and gun?

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