Make procgen use weighted variants (#24669)

Content.Shared/Maps/TileSystem.cs

@@ -25,12 +25,29 @@ public sealed class TileSystem : EntitySystem
     ///     Returns a weighted pick of a tile variant.
     /// </summary>
     public byte PickVariant(ContentTileDefinition tile)
+    {
+        return PickVariant(tile, _robustRandom.GetRandom());
+    }
+
+    /// <summary>
+    ///     Returns a weighted pick of a tile variant.
+    /// </summary>
+    public byte PickVariant(ContentTileDefinition tile, int seed)
+    {
+        var rand = new System.Random(seed);
+        return PickVariant(tile, rand);
+    }
+
+    /// <summary>
+    ///     Returns a weighted pick of a tile variant.
+    /// </summary>
+    public byte PickVariant(ContentTileDefinition tile, System.Random random)
     {
         var variants = tile.PlacementVariants;
 
         var sum = variants.Sum();
         var accumulated = 0f;
-        var rand = _robustRandom.NextFloat() * sum;
+        var rand = random.NextFloat() * sum;
 
         for (byte i = 0; i < variants.Length; ++i)
         {
@@ -44,6 +61,23 @@ public sealed class TileSystem : EntitySystem
         throw new InvalidOperationException($"Invalid weighted variantize tile pick for {tile.ID}!");
     }
 
+    /// <summary>
+    ///     Returns a tile with a weighted random variant.
+    /// </summary>
+    public Tile GetVariantTile(ContentTileDefinition tile, System.Random random)
+    {
+        return new Tile(tile.TileId, variant: PickVariant(tile, random));
+    }
+
+    /// <summary>
+    ///     Returns a tile with a weighted random variant.
+    /// </summary>
+    public Tile GetVariantTile(ContentTileDefinition tile, int seed)
+    {
+        var rand = new System.Random(seed);
+        return new Tile(tile.TileId, variant: PickVariant(tile, rand));
+    }
+
     public bool PryTile(Vector2i indices, EntityUid gridId)
     {
         var grid = Comp<MapGridComponent>(gridId);