MovementTests/systems/head/HeadSystem.cs

using System;
using Godot;

namespace Movementtests.systems;

public partial class HeadSystem : Node3D
{
    private Camera3D _camera;
    private Marker3D _cameraAnchor;
	
    [Export(PropertyHint.Range, "0,10,0.1,or_greater")]
    public float LookSensitivity { get; set; } = 1f;
    
    public void Init()
    {
        Input.SetMouseMode(Input.MouseModeEnum.Captured);
        _camera = GetNode<Camera3D>("CameraSmooth/Camera3D");
        _cameraAnchor = GetNode<Marker3D>("CameraAnchor");
    }

    public void LookAround(Vector2 lookDir, float sensitivitMultiplier = 1f)
    {
        // Horizontal movement of head
        float angleForHorizontalRotation = lookDir.X * LookSensitivity * sensitivitMultiplier;
        RotateY(angleForHorizontalRotation);

        // Vertical movement of head
        Vector3 currentCameraRotation = _cameraAnchor.Rotation;
        currentCameraRotation.X += Convert.ToSingle(lookDir.Y * LookSensitivity * sensitivitMultiplier);
        currentCameraRotation.X = Mathf.Clamp(currentCameraRotation.X, Mathf.DegToRad(-90f), Mathf.DegToRad(90f));
        _cameraAnchor.Rotation = currentCameraRotation;
        
        _camera.GlobalTransform = _cameraAnchor.GetGlobalTransformInterpolated();
    }

    public Vector3 GetForwardHorizontalVector()
    {
        return GetGlobalTransform().Basis.Z;
    }

    public void SetHeight(float height)
    {
        Position = new Vector3(Position.X, height, Position.Z);
    }
}