riversong code showcase

Source/Riversong/Game/EditTools/BuildTool/BuildToolPreview.cs

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+using Unity.Mathematics;
+using UnityEngine;
+using UnityEngine.Pool;
+using Object = UnityEngine.Object;
+
+namespace DanieleMarotta.RiversongCodeShowcase
+{
+    public class BuildToolPreview
+    {
+        private readonly GameConfig.UIConfig.BuildToolConfig _config;
+
+        private readonly ITileSpace _tileSpace;
+
+        private BuildingDefinition _building;
+
+        private Vector3 _tilt;
+
+        private Vector3 _tiltVelocity;
+
+        private float _yaw;
+
+        private float _yawVelocity;
+
+        public BuildToolPreview(GameConfig.UIConfig.BuildToolConfig config, ITileSpace tileSpace)
+        {
+            _config = config;
+            _tileSpace = tileSpace;
+        }
+
+        public GameObject PreviewObject { get; private set; }
+
+        public bool IsVisible => PreviewObject && PreviewObject.activeSelf;
+
+        public float3 Position => PreviewObject ? PreviewObject.transform.position : Vector3.zero;
+
+        public void PrepareForBuilding(BuildingDefinition building)
+        {
+            _building = building;
+        }
+
+        public void Release()
+        {
+            ClearPreviewObject();
+        }
+
+        public void Update(bool isValid, Vector3 pointer, Directions orientation)
+        {
+            if (!PreviewObject)
+            {
+                if (_building.Visualization.IsDone)
+                    CreatePreviewObject();
+                else
+                    return;
+            }
+
+            var snap = !PreviewObject.activeSelf && isValid;
+            if (snap)
+            {
+                _tilt = Vector3.zero;
+                _tiltVelocity = Vector3.zero;
+            }
+
+            PreviewObject.SetActive(isValid);
+            if (!isValid) return;
+
+            var rect = TileMath.GetBuildingRect(_tileSpace.WorldToTile(pointer), orientation, _building.Width, _building.Height);
+            var position = _tileSpace.GetRectWorldCenter(rect);
+            position.y += _config.Height;
+
+            var dt = Time.unscaledDeltaTime;
+
+            position = snap ? position : Vector3.Lerp(PreviewObject.transform.position, position, _config.LerpFactor * dt);
+
+            var yaw = orientation.ToQuaternion().eulerAngles.y;
+            _yaw = snap ? yaw : Mathf.SmoothDampAngle(_yaw, yaw, ref _yawVelocity, 0.1f, Mathf.Infinity, dt);
+            var rotation = Quaternion.Euler(0, _yaw, 0);
+            if (!snap) rotation = SimulateSpring(position, dt) * rotation;
+
+            PreviewObject.transform.SetPositionAndRotation(position, rotation);
+        }
+
+        private Quaternion SimulateSpring(Vector3 targetPosition, float dt)
+        {
+            var positionDelta = targetPosition - PreviewObject.transform.position;
+
+            _tilt -= positionDelta * _config.ImpulseScale;
+            _tilt = _tilt.normalized * Mathf.Min(_tilt.magnitude, _config.MaxTilt);
+
+            _tiltVelocity -= _tilt * (_config.Elasticity * dt);
+            _tiltVelocity *= Mathf.Pow(1 - _config.Damping, dt);
+
+            _tilt += _tiltVelocity * dt;
+
+            if (_tilt.sqrMagnitude > 0.001f)
+            {
+                var axis = Vector3.Cross(Vector3.down, _tilt.normalized);
+                var angle = _tilt.magnitude / _config.MaxTilt * _config.MaxTiltAngle;
+                return Quaternion.AngleAxis(angle, axis);
+            }
+
+            return Quaternion.identity;
+        }
+
+        private void CreatePreviewObject()
+        {
+            PreviewObject = Object.Instantiate((GameObject)_building.Visualization.Asset);
+            PreviewObject.SetLayerRecursively<Renderer>(GameObjectLayers.IgnoreAoE);
+
+            using var _ = ListPool<HideOnBuildingPreview>.Get(out var hide);
+            PreviewObject.GetComponentsInChildren(hide);
+            foreach (var obj in hide) obj.gameObject.SetActive(false);
+
+            // Start the preview in the disabled state, causes the position to be snapped when enabled
+            PreviewObject.SetActive(false);
+        }
+
+        public void ClearPreviewObject()
+        {
+            if (PreviewObject)
+            {
+                Object.Destroy(PreviewObject);
+                PreviewObject = null;
+            }
+        }
+    }
+}