test: end-to-end streaming + modification-store roundtrip

VoxelEngine.Tests/Streaming/StreamingIntegrationTests.cs

@@ -0,0 +1,84 @@
+using OpenTK.Mathematics;
+using VoxelEngine.Core;
+using VoxelEngine.World;
+using VoxelEngine.World.Blocks;
+using VoxelEngine.World.Chunk;
+using VoxelEngine.World.Persistence;
+using VoxelEngine.World.Streaming;
+using VoxelEngine.World.WorldGen;
+using Xunit;
+
+namespace VoxelEngine.Tests.Streaming;
+
+public class StreamingIntegrationTests
+{
+    private static (ChunkStreamer streamer, World.World world, InMemoryChunkModificationStore store)
+        BuildRealStack(Configuration cfg)
+    {
+        var registry = new BlockRegistry();
+        var store = new InMemoryChunkModificationStore();
+        var world = new World.World(registry, store);
+        var gen = new WorldGenerator(seed: 1337, blocks: registry);
+        var mesher = new ChunkMesher(atlasWidthPixels: 128, atlasHeightPixels: 32);
+        var executor = new SynchronousJobExecutor();
+        Func<float[], IChunkRenderer> factory = m => new FakeRenderer(m);
+        var streamer = new ChunkStreamer(cfg, world, gen.Generate, mesher, registry, executor, factory);
+        return (streamer, world, store);
+    }
+
+    [Fact]
+    public void PlayerWalksAcrossWorld_LoadBoxFollowsPlayer()
+    {
+        var cfg = new Configuration
+        {
+            RenderDistanceHorizontal = 1,
+            RenderDistanceVertical = 0,
+            MaxGenerateJobsInFlight = 100,
+            MaxMeshUploadsPerFrame = 100,
+        };
+        var (streamer, world, _) = BuildRealStack(cfg);
+
+        for (int step = 0; step < 5; step++)
+        {
+            streamer.Tick(new Vector3i(step, 0, 0));
+
+            for (int dx = -1; dx <= 1; dx++)
+            for (int dz = -1; dz <= 1; dz++)
+            {
+                var pos = new Vector3i(step + dx, 0, dz);
+                Assert.NotNull(world.GetChunk(pos));
+                Assert.True(streamer.IsReady(pos));
+            }
+        }
+    }
+
+    [Fact]
+    public void ModificationStore_SurvivesUnloadReload()
+    {
+        var cfg = new Configuration
+        {
+            RenderDistanceHorizontal = 0,
+            RenderDistanceVertical = 0,
+            MaxGenerateJobsInFlight = 100,
+            MaxMeshUploadsPerFrame = 100,
+        };
+        var (streamer, world, store) = BuildRealStack(cfg);
+
+        // Use a block id that differs from what WorldGenerator places at
+        // world (0,0,0). At y=0 every biome's "Under" block is Stone (id 1),
+        // so SetBlock(..., Stone) would hit World.SetBlock's no-op guard and
+        // skip the diff record. Dirt (id 2) is always a real change.
+        var pos = new Vector3i(0, 0, 0);
+        streamer.Tick(pos);
+        Assert.True(streamer.IsReady(pos));
+        Assert.True(world.SetBlock(0, 0, 0, /*Dirt*/ (ushort)2));
+
+        streamer.Tick(new Vector3i(50, 0, 0));
+        Assert.Null(world.GetChunk(pos));
+        Assert.True(store.HasDiff(pos));
+
+        streamer.Tick(pos);
+        Assert.NotNull(world.GetChunk(pos));
+        Assert.Equal((ushort)2, world.GetBlock(0, 0, 0).Id);
+    }
+}