riversong code showcase

Source/Riversong/Game/Input/PointerSystem.cs

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+using UnityEngine;
+using UnityEngine.InputSystem;
+using UnityEngine.UIElements;
+
+namespace DanieleMarotta.RiversongCodeShowcase
+{
+    [Service(typeof(IPointerService))]
+    [GameSystemGroup(typeof(EarlyGameSystemGroup))]
+    public class PointerSystem : GameSystem, IUpdatable, IPointerService
+    {
+        [InjectService]
+        private IScene _scene;
+
+        [InjectService]
+        private GameConfig _config;
+
+        [InjectService]
+        private ITileSpace _tileSpace;
+
+        [InjectService]
+        private World _world;
+
+        [InjectService]
+        private UIService _uiService;
+
+        private int _leftButtonClickCount;
+
+        private Vector3? _positionOnTerrain;
+
+        public PointerSystem(IServiceLocator serviceLocator) : base(serviceLocator)
+        {
+        }
+
+        public bool IsPointerOverUI { get; private set; }
+
+        public void Update()
+        {
+            _leftButtonClickCount = 0;
+
+            UpdateIsPointerOverUIFlag();
+
+            UpdatePositionOnTerrain();
+        }
+
+        private void UpdateIsPointerOverUIFlag()
+        {
+            var panel = _uiService.UIRoot.RootVisualElement.panel;
+
+            var position = Mouse.current.position.ReadValue();
+            position.y = Screen.height - position.y;
+            position = RuntimePanelUtils.ScreenToPanel(panel, position);
+
+            IsPointerOverUI = panel.Pick(position) != null;
+        }
+
+        private void UpdatePositionOnTerrain()
+        {
+            _positionOnTerrain = null;
+
+            var ray = _scene.MainCamera.ScreenPointToRay(Mouse.current.position.ReadValue());
+            if (Physics.Raycast(ray, out var hit, float.PositiveInfinity))
+            {
+                if (!Mathf.Approximately(Vector3.Dot(hit.normal, Vector3.up), 1)) return;
+
+                if (_tileSpace.GetElevation(hit.point.y) != _config.GeneralSettings.BaseElevation) return;
+
+                _positionOnTerrain = hit.point;
+            }
+        }
+
+        public bool TryGetPositionOnTerrain(out Vector3 position)
+        {
+            position = _positionOnTerrain ?? Vector3.zero;
+            return _positionOnTerrain != null;
+        }
+
+        public bool TryConsumeLeftClick(int maxClickCount = 0)
+        {
+            return !IsPointerOverUI && Mouse.current.leftButton.wasPressedThisFrame && _leftButtonClickCount++ <= maxClickCount;
+        }
+    }
+}