Enhanced loot drops system

Scripts/Resources/Loot/LootDropHelper.cs

@@ -0,0 +1,68 @@
+using System.Collections.Generic;
+using System.Linq;
+using Godot;
+
+namespace Cirno.Scripts.Resources.Loot;
+
+/// <summary>
+/// Shared logic for spawning and scattering <see cref="LootDrop"/> entries in the 3D world.
+/// Used by both destructibles and enemies so the distribution behaviour stays consistent.
+/// </summary>
+public static class LootDropHelper
+{
+    /// <summary>
+    /// Rolls each drop's chance, then spawns the resulting pickups scattered uniformly
+    /// in a circle around <paramref name="center"/> with an outward + upward launch velocity
+    /// so they arc through the air and fall to the floor.
+    /// </summary>
+    /// <param name="drops">The list of possible drops to evaluate.</param>
+    /// <param name="anchor">Node used as the spawn parent / sibling reference.</param>
+    /// <param name="center">World-space centre of the scatter circle.</param>
+    /// <param name="scatterRadius">Radius of the circle in which items are spread.</param>
+    /// <param name="launchUpSpeed">Initial upward speed applied to each pickup.</param>
+    /// <param name="rng">Caller-owned RNG instance so seeds are consistent per object.</param>
+    public static void SpawnDrops(
+        IEnumerable<LootDrop> drops,
+        Node3D anchor,
+        Vector3 center,
+        float scatterRadius,
+        float launchUpSpeed,
+        RandomNumberGenerator rng)
+    {
+        var dropList = drops?.ToList();
+        if (dropList is not { Count: > 0 }) return;
+
+        // Count total spawns up front so golden-angle spacing is proportional to the full set.
+        var totalSpawns = dropList
+            .Where(d => d?.Item is not null)
+            .Sum(d => Mathf.Max(d.Count, 1));
+
+        var itemIndex = 0;
+
+        foreach (var drop in dropList)
+        {
+            if (drop?.Item is null) continue;
+
+            var roll = rng.RandfRange(0f, 100f);
+            if (roll > drop.Chance) continue;
+
+            var spawnCount = Mathf.Max(drop.Count, 1);
+            for (var i = 0; i < spawnCount; i++)
+            {
+                // Golden-angle placement gives uniform, non-clustering distribution.
+                itemIndex++;
+                var angle = itemIndex * Mathf.Tau / 1.618033988f;
+                var radius = scatterRadius * Mathf.Sqrt((float)itemIndex / Mathf.Max(totalSpawns, 1));
+                var offset = new Vector3(Mathf.Cos(angle) * radius, 0f, Mathf.Sin(angle) * radius);
+                var spawnPos = center + offset;
+
+                var lateralDir = offset.LengthSquared() > 0f ? offset.Normalized() : Vector3.Right;
+                var launch = lateralDir * (scatterRadius * 0.5f) + Vector3.Up * launchUpSpeed;
+
+                drop.Item.Spawn3D(anchor, spawnPosition: spawnPos, launchVelocity: launch);
+            }
+        }
+    }
+}
+
+