Deferred cave pool terrain

- Opened the cave pool terrain view only for chunks that draw a pool site
- Added a test that chunks without a pool site never open their caves

core/src/main/java/art/arcane/iris/generation/hydrology/underground/CavePoolFiller.java

@@ -10,6 +10,7 @@ import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
 
 import java.util.Arrays;
 import java.util.Set;
+import java.util.function.Supplier;
 
 public final class CavePoolFiller {
     public static final int REACH = HydrologySettings.MAX_CAVE_POOL_RADIUS + 1;
@@ -40,15 +41,19 @@ public final class CavePoolFiller {
         this.density = settings.density();
     }
 
-    public void fill(int chunkX, int chunkZ, CarvedTerrain carved, MantleWriter writer, long seed) {
+    public void fill(int chunkX, int chunkZ, Supplier<? extends CarvedTerrain> terrain, MantleWriter writer, long seed) {
         if (!pools.enabled() || density == 0f) {
             return;
         }
         int attempts = attempts(seed, chunkX, chunkZ);
+        CarvedTerrain carved = null;
         for (int attempt = 0; attempt < attempts; attempt++) {
             if (density < 1f && CellHash.unit(CellHash.mix(seed, SALT_DENSITY + attempt, chunkX, chunkZ)) >= density) {
                 continue;
             }
+            if (carved == null) {
+                carved = terrain.get();
+            }
             long column = CellHash.mix(seed, SALT_COLUMN + attempt, chunkX, chunkZ);
             int x = (chunkX << 4) + (int) (column & 15);
             int z = (chunkZ << 4) + (int) ((column >>> 4) & 15);

core/src/main/java/art/arcane/iris/generation/mantle/MantleHydrologyComponent.java

@@ -85,8 +85,9 @@ public final class MantleHydrologyComponent extends IrisMantleComponent {
         generateFalls(writer, complex, runtime, own, chunkX, chunkZ);
         if (poolsActive()) {
             HydrologySettings settings = runtime.settings();
-            new CavePoolFiller(settings).fill(chunkX, chunkZ,
-                    new MantleCarvedTerrain(writer, complex, getEngineMantle().getEngine(), chunkX, chunkZ), writer, settings.seed());
+            Engine engine = getEngineMantle().getEngine();
+            new CavePoolFiller(settings).fill(chunkX, chunkZ, () -> new MantleCarvedTerrain(writer, complex, engine, chunkX, chunkZ), writer,
+                    settings.seed());
         }
     }
 

core/src/test/java/art/arcane/iris/generation/hydrology/underground/CavePoolFillerTest.java

@@ -15,6 +15,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Consumer;
 import java.util.function.IntFunction;
 
@@ -50,18 +51,37 @@ public class CavePoolFillerTest {
             return 0;
         });
         for (int chunkX = 0; chunkX < 1024; chunkX++) {
-            filler.fill(chunkX, 0, carved, writer, SEED);
+            filler.fill(chunkX, 0, () -> carved, writer, SEED);
         }
         assertTrue("half density samples approximately half the candidate columns", columns.size() > 3600 && columns.size() < 4500);
         Set<Long> repeated = new HashSet<>(columns);
         columns.clear();
         for (int chunkX = 1023; chunkX >= 0; chunkX--) {
-            filler.fill(chunkX, 0, carved, writer, SEED);
+            filler.fill(chunkX, 0, () -> carved, writer, SEED);
         }
         assertEquals(repeated, columns);
         verifyNoInteractions(writer);
     }
 
+    @Test
+    public void chunksWithoutAPoolSiteNeverOpenTheirCaves() {
+        IrisHydrology config = new IrisHydrology().setDensity(0.5D);
+        config.getUnderground().getCavePools().setDensity(0.05D);
+        CavePoolFiller filler = new CavePoolFiller(HydrologySettings.compile(config, SEED, 63, 0, 384));
+        CarvedTerrain carved = mock(CarvedTerrain.class);
+        MantleWriter writer = mock(MantleWriter.class);
+        AtomicInteger opened = new AtomicInteger();
+        int chunks = 1024;
+        for (int chunkX = 0; chunkX < chunks; chunkX++) {
+            filler.fill(chunkX, 0, () -> {
+                opened.incrementAndGet();
+                return carved;
+            }, writer, SEED);
+        }
+        assertTrue("only chunks drawing a pool site open their caves, opened " + opened.get(), opened.get() > 0 && opened.get() < chunks / 8);
+        verifyNoInteractions(writer);
+    }
+
     @Test
     public void zeroGlobalDensityDoesNotReadCaves() {
         IrisHydrology config = new IrisHydrology().setDensity(0D);
@@ -69,7 +89,7 @@ public class CavePoolFillerTest {
         CavePoolFiller filler = new CavePoolFiller(HydrologySettings.compile(config, SEED, 63, 0, 384));
         CarvedTerrain carved = mock(CarvedTerrain.class);
         MantleWriter writer = mock(MantleWriter.class);
-        filler.fill(0, 0, carved, writer, SEED);
+        filler.fill(0, 0, () -> carved, writer, SEED);
         verifyNoInteractions(carved, writer);
     }
 
@@ -143,10 +163,10 @@ public class CavePoolFillerTest {
         MantleWriter forwardWriter = writer(forward);
         MantleWriter reverseWriter = writer(reverse);
         for (int index = 0; index < 9; index++) {
-            new CavePoolFiller(settings).fill(index % 3 - 1, index / 3 - 1, world, forwardWriter, SEED);
+            new CavePoolFiller(settings).fill(index % 3 - 1, index / 3 - 1, () -> world, forwardWriter, SEED);
         }
         for (int index = 8; index >= 0; index--) {
-            new CavePoolFiller(settings).fill(index % 3 - 1, index / 3 - 1, world, reverseWriter, SEED);
+            new CavePoolFiller(settings).fill(index % 3 - 1, index / 3 - 1, () -> world, reverseWriter, SEED);
         }
 
         assertFalse(forward.isEmpty());
@@ -284,7 +304,7 @@ public class CavePoolFillerTest {
 
     private static Map<Long, HydrologyCaveCell> fill(HydrologySettings settings, VoxelWorld world, int chunkX, int chunkZ) {
         Map<Long, HydrologyCaveCell> written = new HashMap<>();
-        new CavePoolFiller(settings).fill(chunkX, chunkZ, world, writer(written), SEED);
+        new CavePoolFiller(settings).fill(chunkX, chunkZ, () -> world, writer(written), SEED);
         return written;
     }
 

core/src/test/java/art/arcane/iris/generation/mantle/MantleCarvedTerrainTest.java

@@ -324,7 +324,7 @@ public class MantleCarvedTerrainTest {
                 for (SeaInlet inlet : complex.getHydrologyRuntime().inlets(0, chunkZ)) {
                     rasterizer.write(inlet, 0, chunkZ, writer, HydrologyCaveCell.SEA_FLUID, "", SeaInletRasterizer.SubterrainFluid.NOWHERE);
                 }
-                new CavePoolFiller(settings).fill(0, chunkZ, new MantleCarvedTerrain(writer, complex, engine, 0, chunkZ), writer, SEED);
+                new CavePoolFiller(settings).fill(0, chunkZ, () -> new MantleCarvedTerrain(writer, complex, engine, 0, chunkZ), writer, SEED);
             }
             return cells;
         }