Dynamic space world generation and debris. (#15120)

* World generation (squash)

* Test fixes.

* command

* o

* Access cleanup.

* Documentation touchups.

* Use a prototype serializer for BiomeSelectionComponent

* Struct enumerator in SimpleFloorPlanPopulatorSystem

* Safety margins around PoissonDiskSampler, cookie acquisition methodologies

* Struct enumerating PoissonDiskSampler; internal side

* Struct enumerating PoissonDiskSampler: Finish it

* Update WorldgenConfigSystem.cs

awa

---------

Co-authored-by: moonheart08 <moonheart08@users.noreply.github.com>
Co-authored-by: 20kdc <asdd2808@gmail.com>

Content.Server/Worldgen/Systems/Debris/SimpleFloorPlanPopulatorSystem.cs

@@ -0,0 +1,49 @@
+using Content.Server.Worldgen.Components.Debris;
+using Content.Shared.Maps;
+using Robust.Shared.Map;
+using Robust.Shared.Map.Components;
+using Robust.Shared.Random;
+
+namespace Content.Server.Worldgen.Systems.Debris;
+
+/// <summary>
+///     This handles populating simple structures, simply using a loot table for each tile.
+/// </summary>
+public sealed class SimpleFloorPlanPopulatorSystem : BaseWorldSystem
+{
+    [Dependency] private readonly IRobustRandom _random = default!;
+    [Dependency] private readonly ITileDefinitionManager _tileDefinition = default!;
+
+    /// <inheritdoc />
+    public override void Initialize()
+    {
+        SubscribeLocalEvent<SimpleFloorPlanPopulatorComponent, LocalStructureLoadedEvent>(OnFloorPlanBuilt);
+    }
+
+    private void OnFloorPlanBuilt(EntityUid uid, SimpleFloorPlanPopulatorComponent component,
+        LocalStructureLoadedEvent args)
+    {
+        var placeables = new List<string?>(4);
+        var grid = Comp<MapGridComponent>(uid);
+        var enumerator = grid.GetAllTilesEnumerator();
+        while (enumerator.MoveNext(out var tile))
+        {
+            var coords = grid.GridTileToLocal(tile.Value.GridIndices);
+            var selector = tile.Value.Tile.GetContentTileDefinition(_tileDefinition).ID;
+            if (!component.Caches.TryGetValue(selector, out var cache))
+                continue;
+
+            placeables.Clear();
+            cache.GetSpawns(_random, ref placeables);
+
+            foreach (var proto in placeables)
+            {
+                if (proto is null)
+                    continue;
+
+                Spawn(proto, coords);
+            }
+        }
+    }
+}
+