feat(world-gen): integrate CaveCarver into WorldGenerator.Generate

Core/Game.cs

@@ -55,7 +55,7 @@ public sealed class Game : GameWindow
         this._world = new World.World(this._registry, this._modStore);
 
         int seed = this._cfg.Seed ?? new Random().Next();
-        this._generator = new WorldGenerator(seed, this._registry);
+        this._generator = new WorldGenerator(seed, this._registry, this._cfg);
 
         // Spawn at terrain surface above (0, 0).
         int surfaceY = this._generator.SurfaceHeightAt(0, 0);

VoxelEngine.Tests/Streaming/StreamingIntegrationTests.cs

@@ -18,7 +18,7 @@ public class StreamingIntegrationTests
         var registry = new BlockRegistry();
         var store = new InMemoryChunkModificationStore();
         var world = new World.World(registry, store);
-        var gen = new WorldGenerator(seed: 1337, blocks: registry);
+        var gen = new WorldGenerator(seed: 1337, blocks: registry, cfg: new Configuration());
         var mesher = new ChunkMesher(atlasWidthPixels: 128, atlasHeightPixels: 32);
         var executor = new SynchronousJobExecutor();
         Func<float[], IChunkRenderer> factory = m => new FakeRenderer(m);

VoxelEngine.Tests/WorldGen/WorldGeneratorTests.cs

@@ -1,4 +1,5 @@
 using OpenTK.Mathematics;
+using VoxelEngine.Core;
 using VoxelEngine.World.Blocks;
 using VoxelEngine.World.Chunk;
 using VoxelEngine.World.WorldGen;
@@ -58,8 +59,8 @@ public class WorldGeneratorTests
     [Fact]
     public void Generate_IsDeterministic()
     {
-        var gen1 = new WorldGenerator(99, Blocks);
+        var gen1 = new WorldGenerator(99, Blocks, new Configuration());
-        var gen2 = new WorldGenerator(99, Blocks);
+        var gen2 = new WorldGenerator(99, Blocks, new Configuration());
         Chunk a = gen1.Generate(new Vector3i(0, 4, 0));
         Chunk b = gen2.Generate(new Vector3i(0, 4, 0));
         for (int x = 0; x < Chunk.Size; x++)
@@ -67,4 +68,32 @@ public class WorldGeneratorTests
         for (int z = 0; z < Chunk.Size; z++)
             Assert.Equal(a[x, y, z], b[x, y, z]);
     }
+
+    [Fact]
+    public void Generate_AppliesCaves_ProducesAirVoxelsBelowSurface()
+    {
+        var gen = new WorldGenerator(seed: 12345, Blocks, new Configuration());
+        // A chunk well below typical surface height — guaranteed mostly stone before carving.
+        Chunk c = gen.Generate(new Vector3i(0, 1, 0)); // worldY = 16..31
+
+        int airCount = 0;
+        for (int x = 0; x < Chunk.Size; x++)
+        for (int y = 0; y < Chunk.Size; y++)
+        for (int z = 0; z < Chunk.Size; z++)
+            if (c[x, y, z] == Blocks.Air.Id) airCount++;
+
+        Assert.True(airCount > 0,
+            "Deep chunk had zero air voxels after generation — caves not running?");
+    }
+
+    [Fact]
+    public void Generate_PreservesBedrockFloor_Y0_IsStone()
+    {
+        var gen = new WorldGenerator(seed: 12345, Blocks, new Configuration());
+        Chunk c = gen.Generate(new Vector3i(0, 0, 0)); // worldY = 0..15
+
+        for (int x = 0; x < Chunk.Size; x++)
+        for (int z = 0; z < Chunk.Size; z++)
+            Assert.Equal(Blocks.Stone.Id, c[x, 0, z]);
+    }
 }

World/WorldGen/WorldGenerator.cs

@@ -1,4 +1,5 @@
 using OpenTK.Mathematics;
+using VoxelEngine.Core;
 using VoxelEngine.World.Blocks;
 using VoxelChunk = VoxelEngine.World.Chunk.Chunk;
 
@@ -12,8 +13,9 @@ public sealed class WorldGenerator
     private readonly BlockRegistry _blocks;
     private readonly BiomeMap _biomeMap;
     private readonly TerrainSampler _terrain;
+    private readonly CaveCarver _caves;
 
-    public WorldGenerator(int seed, BlockRegistry blocks)
+    public WorldGenerator(int seed, BlockRegistry blocks, Configuration cfg)
     {
         this._blocks = blocks;
         NoiseSource noise = new(seed);
@@ -21,6 +23,7 @@ public sealed class WorldGenerator
         BiomeRegistry biomes = new(seed, blocks);
         this._biomeMap = new BiomeMap(noise, cells, biomes);
         this._terrain = new TerrainSampler(noise, this._biomeMap);
+        this._caves = new CaveCarver(seed, blocks, cfg);
     }
 
     public int SurfaceHeightAt(int worldX, int worldZ) => this._terrain.HeightAt(worldX, worldZ);
@@ -46,10 +49,11 @@ public sealed class WorldGenerator
                 chunk[x, y, z] = WorldGenerator.BlockAt(worldY, height, biome, this._blocks);
             }
         }
+
+        this._caves.Carve(chunk, chunkPos);
         return chunk;
     }
 
-    // Pure column fill rule, extracted for testability.
     public static ushort BlockAt(int worldY, int surfaceHeight, IBiome biome, BlockRegistry blocks)
     {
         if (worldY > surfaceHeight)