riversong-code-showcase/Source/Riversong/Game/Camera/CameraSystem.cs

using Cysharp.Threading.Tasks;
using Unity.Cinemachine;
using UnityEngine;
using UnityEngine.InputSystem;

namespace DanieleMarotta.RiversongCodeShowcase
{
    [Service(typeof(ICameraProperties))]
    public class CameraSystem : GameSystem, IInitializable, IUpdatable, ICameraProperties
    {
        [InjectService]
        private GameConfig _gameConfig;

        [InjectService]
        private IScene _scene;

        private GameConfig.CameraConfig _cameraConfig;

        private CinemachineBrain _cinemachineBrain;

        private CinemachineFollow _cinemachineFollow;

        private Transform _target;

        private float _targetZoom;

        private Vector3? _terrainDragAnchor;

        public CameraSystem(IServiceLocator serviceLocator) : base(serviceLocator)
        {
        }

        public float Zoom { get; private set; }

        public UniTask InitializeAsync()
        {
            _cameraConfig = _gameConfig.Camera;

            _cinemachineBrain = _scene.MainCamera.GetComponent<CinemachineBrain>();

            _cinemachineFollow = (CinemachineFollow)_scene.CinemachineCamera.GetCinemachineComponent(CinemachineCore.Stage.Body);
            _target = _cinemachineFollow.FollowTarget;

            Zoom = _targetZoom = _cinemachineFollow.FollowOffset.magnitude;

            return UniTask.CompletedTask;
        }

        public void Update()
        {
            var dt = Time.unscaledDeltaTime;

            UpdateZoom(dt);
            UpdatePosition(dt);
            UpdateRotation(dt);

            _cinemachineBrain.ManualUpdate();
        }

        private void UpdateZoom(float dt)
        {
            var zoomInput = -1 * Mouse.current.scroll.y.ReadValue();

            _targetZoom += zoomInput * _cameraConfig.ZoomSensitivity;
            _targetZoom = Mathf.Clamp(_targetZoom, _cameraConfig.ZoomRange.x, _cameraConfig.ZoomRange.y);

            Zoom = Mathf.Lerp(Zoom, _targetZoom, _cameraConfig.ZoomSpeed * dt);

            _cinemachineFollow.FollowOffset = _cinemachineFollow.FollowOffset.normalized * Zoom;
        }

        private void UpdatePosition(float dt)
        {
            var moveInput = Vector3.zero;

            moveInput.x += Keyboard.current.dKey.isPressed ? 1 : 0;
            moveInput.x += Keyboard.current.aKey.isPressed ? -1 : 0;
            moveInput.z += Keyboard.current.wKey.isPressed ? 1 : 0;
            moveInput.z += Keyboard.current.sKey.isPressed ? -1 : 0;

            var right = _target.right;
            var forward = _target.forward;
            forward.y = 0;
            forward.Normalize();

            var normalizedZoom = Mathf.InverseLerp(_cameraConfig.ZoomRange.x, _cameraConfig.ZoomRange.y, Zoom);
            var moveSpeed = Mathf.Lerp(_cameraConfig.MoveSpeed.x, _cameraConfig.MoveSpeed.y, normalizedZoom);
            var delta = moveSpeed * dt;

            _target.position += right * (moveInput.x * delta);
            _target.position += forward * (moveInput.z * delta);

            UpdateDraggingTerrain();
        }

        private void UpdateDraggingTerrain()
        {
            if (!Mouse.current.middleButton.isPressed)
            {
                _terrainDragAnchor = null;
                return;
            }

            var plane = new Plane(Vector3.up, new Vector3(0, _gameConfig.GeneralSettings.BaseElevation, 0));
            var ray = _scene.MainCamera.ScreenPointToRay(Mouse.current.position.ReadValue());
            if (!plane.Raycast(ray, out var enter)) return;

            var hit = ray.GetPoint(enter);
            if (_terrainDragAnchor == null)
            {
                _terrainDragAnchor = hit;
                return;
            }

            _target.position += _terrainDragAnchor.Value - hit;
        }

        private void UpdateRotation(float dt)
        {
            var keyboard = Keyboard.current;
            var rotation = _target.rotation.eulerAngles;
            var keyboardRotationDelta = Vector2.zero;

            keyboardRotationDelta.x += keyboard.eKey.isPressed ? 1 : 0;
            keyboardRotationDelta.x += keyboard.qKey.isPressed ? -1 : 0;
            keyboardRotationDelta.y += keyboard.rKey.isPressed ? 1 : 0;
            keyboardRotationDelta.y += keyboard.fKey.isPressed ? -1 : 0;

            rotation.y += keyboardRotationDelta.x * _cameraConfig.KeyboardRotationSpeed.x * dt;
            rotation.x -= keyboardRotationDelta.y * _cameraConfig.KeyboardRotationSpeed.y * dt;

            if (keyboard.leftAltKey.isPressed)
            {
                var mouseDelta = Mouse.current.delta;

                rotation.x += mouseDelta.y.ReadValue() * _cameraConfig.MouseRotationSpeed.y * dt;
                rotation.y += mouseDelta.x.ReadValue() * _cameraConfig.MouseRotationSpeed.x * dt;
            }

            rotation.x = Mathf.Clamp(rotation.x, _cameraConfig.PitchRange.x, _cameraConfig.PitchRange.y);

            _target.forward = Quaternion.Euler(rotation) * Vector3.forward;
        }
    }
}