floatt

core/src/main/java/art/arcane/iris/core/nms/INMSBinding.java

@@ -46,7 +46,6 @@ import org.bukkit.inventory.ItemStack;
 
 import java.awt.Color;
 import java.util.List;
-import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 
 public interface INMSBinding {
@@ -162,10 +161,6 @@ public interface INMSBinding {
 
     KMap<Material, List<BlockProperty>> getBlockProperties();
 
-    default Map<String, byte[]> extractVanillaDatapack() {
-        return Map.of();
-    }
-
     private void validateDimensionTypes(WorldCreator c) {
         if (c.generator() instanceof PlatformChunkGenerator gen
                 && missingDimensionTypes(gen.getTarget().getDimension().getDimensionTypeKey())) {

core/src/main/java/art/arcane/iris/engine/decorator/FloatingDecorator.java

@@ -0,0 +1,134 @@
+/*
+ * Iris is a World Generator for Minecraft Bukkit Servers
+ * Copyright (c) 2022 Arcane Arts (Volmit Software)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package art.arcane.iris.engine.decorator;
+
+import art.arcane.iris.Iris;
+import art.arcane.iris.engine.framework.Engine;
+import art.arcane.iris.engine.object.IrisBiome;
+import art.arcane.iris.engine.object.IrisDecorationPart;
+import art.arcane.iris.engine.object.IrisDecorator;
+import art.arcane.iris.util.project.hunk.Hunk;
+import art.arcane.volmlib.util.collection.KList;
+import art.arcane.volmlib.util.math.RNG;
+import org.bukkit.block.data.Bisected;
+import org.bukkit.block.data.BlockData;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+/*
+ * Floating island decoration path. Bypasses all canGoOn, slope, whitelist, and blacklist
+ * gating from IrisSurfaceDecorator — the island top IS the biome's designated surface by
+ * construction, so those material-compatibility checks are never meaningful here.
+ */
+public class FloatingDecorator {
+    public static final AtomicLong decCandidatesNull = new AtomicLong();
+
+    private static final long SEED_SALT = 29356788L;
+    private static final long PART_SALT = 10439677L;
+
+    public static int decorateColumn(Engine engine, IrisBiome target, IrisDecorationPart part,
+                                     int xf, int zf, int realX, int realZ,
+                                     int height, int max, Hunk<BlockData> data, RNG rng) {
+        long gSeed = engine.getSeedManager().getDecorator() + SEED_SALT - (part.ordinal() * PART_SALT);
+        RNG gRNG = new RNG(gSeed);
+        KList<IrisDecorator> candidates = new KList<>();
+
+        for (IrisDecorator d : target.getDecorators()) {
+            try {
+                if (d.getPartOf().equals(part) && d.getBlockData(target, gRNG, realX, realZ, engine.getData()) != null) {
+                    candidates.add(d);
+                }
+            } catch (Throwable e) {
+                Iris.reportError(e);
+            }
+        }
+
+        if (candidates.isEmpty()) {
+            decCandidatesNull.incrementAndGet();
+            return 0;
+        }
+
+        IrisDecorator decorator = candidates.get(rng.nextInt(candidates.size()));
+
+        if (!decorator.isStacking()) {
+            return placeSimple(decorator, target, xf, zf, realX, realZ, height, max, data, rng, engine);
+        } else {
+            return placeStacked(decorator, target, xf, zf, realX, realZ, height, max, data, rng, engine);
+        }
+    }
+
+    private static int placeSimple(IrisDecorator decorator, IrisBiome target,
+                                   int xf, int zf, int realX, int realZ,
+                                   int height, int max, Hunk<BlockData> data, RNG rng, Engine engine) {
+        BlockData bd = decorator.getBlockData100(target, rng, realX, height, realZ, engine.getData());
+        if (bd == null) {
+            return 0;
+        }
+
+        if (bd instanceof Bisected) {
+            BlockData top = bd.clone();
+            ((Bisected) top).setHalf(Bisected.Half.TOP);
+            try {
+                if (max > 2) {
+                    data.set(xf, height + 2, zf, top);
+                }
+            } catch (Throwable e) {
+                Iris.reportError(e);
+            }
+            bd = bd.clone();
+            ((Bisected) bd).setHalf(Bisected.Half.BOTTOM);
+        }
+
+        if (max > 1) {
+            data.set(xf, height + 1, zf, bd);
+            return 1;
+        }
+        return 0;
+    }
+
+    private static int placeStacked(IrisDecorator decorator, IrisBiome target,
+                                    int xf, int zf, int realX, int realZ,
+                                    int height, int max, Hunk<BlockData> data, RNG rng, Engine engine) {
+        int stack = decorator.getHeight(rng, realX, realZ, engine.getData());
+
+        if (decorator.isScaleStack()) {
+            stack = Math.min((int) Math.ceil((double) max * ((double) stack / 100)), decorator.getAbsoluteMaxStack());
+        } else {
+            stack = Math.min(max, stack);
+        }
+
+        int placed = 0;
+        for (int i = 0; i < stack; i++) {
+            int h = height + 1 + i;
+            if (h >= height + max) {
+                break;
+            }
+            double threshold = stack == 1 ? 0.0 : ((double) i) / (stack - 1);
+            BlockData bd = threshold >= decorator.getTopThreshold()
+                    ? decorator.getBlockDataForTop(target, rng, realX, height + i, realZ, engine.getData())
+                    : decorator.getBlockData100(target, rng, realX, height + i, realZ, engine.getData());
+            if (bd == null) {
+                break;
+            }
+            data.set(xf, h, zf, bd);
+            placed++;
+        }
+        return placed;
+    }
+}

core/src/main/java/art/arcane/iris/engine/decorator/IrisFloatingSurfaceDecorator.java

@@ -1,33 +0,0 @@
-/*
- * Iris is a World Generator for Minecraft Bukkit Servers
- * Copyright (c) 2022 Arcane Arts (Volmit Software)
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-package art.arcane.iris.engine.decorator;
-
-import art.arcane.iris.engine.framework.Engine;
-import art.arcane.iris.engine.object.IrisDecorator;
-
-public class IrisFloatingSurfaceDecorator extends IrisSurfaceDecorator {
-    public IrisFloatingSurfaceDecorator(Engine engine) {
-        super(engine, "Floating Surface");
-    }
-
-    @Override
-    protected boolean isSlopeValid(IrisDecorator decorator, int realX, int realZ) {
-        return true;
-    }
-}

core/src/main/java/art/arcane/iris/engine/mantle/components/IslandObjectPlacer.java

@@ -0,0 +1,213 @@
+/*
+ * Iris is a World Generator for Minecraft Bukkit Servers
+ * Copyright (c) 2022 Arcane Arts (Volmit Software)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package art.arcane.iris.engine.mantle.components;
+
+import art.arcane.iris.core.loader.IrisData;
+import art.arcane.iris.engine.framework.Engine;
+import art.arcane.iris.engine.mantle.MantleWriter;
+import art.arcane.iris.engine.object.FloatingIslandSample;
+import art.arcane.iris.engine.object.IObjectPlacer;
+import art.arcane.iris.engine.object.TileData;
+import art.arcane.iris.util.common.data.B;
+import org.bukkit.block.data.BlockData;
+import org.jetbrains.annotations.Nullable;
+
+public class IslandObjectPlacer implements IObjectPlacer {
+    private static final int OVERHANG_RADIUS = 2;
+
+    private final MantleWriter wrapped;
+    private final FloatingIslandSample[] samples;
+    private final int minX;
+    private final int minZ;
+    private final int chunkMaxIslandTopY;
+    private final int anchorTopY;
+    private int writesAttempted;
+    private int writesDroppedBelow;
+    private int writesDroppedOverhang;
+
+    public IslandObjectPlacer(MantleWriter wrapped, FloatingIslandSample[] samples, int minX, int minZ, int anchorTopY) {
+        this.wrapped = wrapped;
+        this.samples = samples;
+        this.minX = minX;
+        this.minZ = minZ;
+        this.anchorTopY = anchorTopY;
+        int maxY = -1;
+        for (FloatingIslandSample s : samples) {
+            if (s != null) {
+                int ty = s.topY();
+                if (ty > maxY) {
+                    maxY = ty;
+                }
+            }
+        }
+        this.chunkMaxIslandTopY = maxY;
+    }
+
+    public int getWritesAttempted() {
+        return writesAttempted;
+    }
+
+    public int getWritesDroppedBelow() {
+        return writesDroppedBelow;
+    }
+
+    public int getWritesDroppedOverhang() {
+        return writesDroppedOverhang;
+    }
+
+    private boolean shouldSkipAirColumn(int x, int y, int z) {
+        writesAttempted++;
+        if (sampleAt(x, z) != null) {
+            return false;
+        }
+        if (y <= anchorTopY) {
+            writesDroppedBelow++;
+            return true;
+        }
+        if (!hasIslandNeighborWithin(x, z, OVERHANG_RADIUS)) {
+            writesDroppedOverhang++;
+            return true;
+        }
+        return false;
+    }
+
+    private boolean hasIslandNeighborWithin(int x, int z, int radius) {
+        int xf = x - minX;
+        int zf = z - minZ;
+        boolean touchedChunkEdge = false;
+        for (int dx = -radius; dx <= radius; dx++) {
+            int nxf = xf + dx;
+            for (int dz = -radius; dz <= radius; dz++) {
+                int nzf = zf + dz;
+                if (nxf < 0 || nxf >= 16 || nzf < 0 || nzf >= 16) {
+                    touchedChunkEdge = true;
+                    continue;
+                }
+                if (samples[(nzf << 4) | nxf] != null) {
+                    return true;
+                }
+            }
+        }
+        return touchedChunkEdge;
+    }
+
+    private @Nullable FloatingIslandSample sampleAt(int x, int z) {
+        int xf = x - minX;
+        int zf = z - minZ;
+        if (xf < 0 || xf >= 16 || zf < 0 || zf >= 16) {
+            return null;
+        }
+        return samples[(zf << 4) | xf];
+    }
+
+    @Override
+    public int getHighest(int x, int z, IrisData data) {
+        FloatingIslandSample s = sampleAt(x, z);
+        if (s != null) {
+            return s.topY();
+        }
+        return chunkMaxIslandTopY;
+    }
+
+    @Override
+    public int getHighest(int x, int z, IrisData data, boolean ignoreFluid) {
+        FloatingIslandSample s = sampleAt(x, z);
+        if (s != null) {
+            return s.topY();
+        }
+        return chunkMaxIslandTopY;
+    }
+
+    @Override
+    public boolean isUnderwater(int x, int z) {
+        return false;
+    }
+
+    @Override
+    public boolean isSolid(int x, int y, int z) {
+        FloatingIslandSample s = sampleAt(x, z);
+        if (s != null) {
+            int idx = y - s.islandBaseY;
+            if (idx >= 0 && idx < s.solidMask.length) {
+                return s.solidMask[idx];
+            }
+            return false;
+        }
+        return wrapped.isSolid(x, y, z);
+    }
+
+    @Override
+    public boolean isCarved(int x, int y, int z) {
+        return wrapped.isCarved(x, y, z);
+    }
+
+    @Override
+    public void set(int x, int y, int z, BlockData d) {
+        if (shouldSkipAirColumn(x, y, z)) {
+            return;
+        }
+        wrapped.set(x, y, z, d);
+    }
+
+    @Override
+    public BlockData get(int x, int y, int z) {
+        return wrapped.get(x, y, z);
+    }
+
+    @Override
+    public boolean isPreventingDecay() {
+        return wrapped.isPreventingDecay();
+    }
+
+    @Override
+    public int getFluidHeight() {
+        return wrapped.getFluidHeight();
+    }
+
+    @Override
+    public boolean isDebugSmartBore() {
+        return wrapped.isDebugSmartBore();
+    }
+
+    @Override
+    public void setTile(int xx, int yy, int zz, TileData tile) {
+        if (shouldSkipAirColumn(xx, yy, zz)) {
+            return;
+        }
+        wrapped.setTile(xx, yy, zz, tile);
+    }
+
+    @Override
+    public <T> void setData(int xx, int yy, int zz, T data) {
+        if (shouldSkipAirColumn(xx, yy, zz)) {
+            return;
+        }
+        wrapped.setData(xx, yy, zz, data);
+    }
+
+    @Override
+    public <T> @Nullable T getData(int xx, int yy, int zz, Class<T> t) {
+        return wrapped.getData(xx, yy, zz, t);
+    }
+
+    @Override
+    public Engine getEngine() {
+        return wrapped.getEngine();
+    }
+}

core/src/main/java/art/arcane/iris/engine/mantle/components/MantleFloatingObjectComponent.java

@@ -27,12 +27,14 @@ import art.arcane.iris.engine.mantle.EngineMantle;
 import art.arcane.iris.engine.mantle.IrisMantleComponent;
 import art.arcane.iris.engine.mantle.MantleWriter;
 import art.arcane.iris.engine.modifier.IrisFloatingChildBiomeModifier;
-import art.arcane.iris.engine.object.CarvingMode;
 import art.arcane.iris.engine.object.FloatingIslandSample;
+import art.arcane.iris.engine.object.FloatingObjectFootprint;
 import art.arcane.iris.engine.object.IrisBiome;
 import art.arcane.iris.engine.object.IrisFloatingChildBiomes;
 import art.arcane.iris.engine.object.IrisObject;
 import art.arcane.iris.engine.object.IrisObjectPlacement;
+import art.arcane.iris.engine.object.IrisObjectRotation;
+import art.arcane.iris.engine.object.IrisObjectTranslate;
 import art.arcane.iris.engine.object.ObjectPlaceMode;
 import art.arcane.iris.util.project.context.ChunkContext;
 import art.arcane.volmlib.util.collection.KList;
@@ -40,13 +42,108 @@ import art.arcane.volmlib.util.documentation.ChunkCoordinates;
 import art.arcane.volmlib.util.mantle.flag.ReservedFlag;
 import art.arcane.volmlib.util.math.RNG;
 
+import java.util.concurrent.atomic.AtomicLong;
+
 @ComponentFlag(ReservedFlag.FLOATING_OBJECT)
 public class MantleFloatingObjectComponent extends IrisMantleComponent {
+    public static final AtomicLong objectsAttempted = new AtomicLong();
+    public static final AtomicLong objectsPlaced = new AtomicLong();
+    public static final AtomicLong objectsSkippedNoFlat = new AtomicLong();
+    public static final AtomicLong objectsSkippedNoInterior = new AtomicLong();
+    public static final AtomicLong objectsRelaxed = new AtomicLong();
+    public static final AtomicLong objectsSkippedShrink = new AtomicLong();
+    public static final AtomicLong objectsSkippedNullObj = new AtomicLong();
+    public static final AtomicLong terrainMismatchWarnings = new AtomicLong();
+    public static final AtomicLong writesAttemptedTotal = new AtomicLong();
+    public static final AtomicLong writesDroppedBelowTotal = new AtomicLong();
+    public static final AtomicLong writesDroppedOverhangTotal = new AtomicLong();
+    private static final int TERRAIN_MISMATCH_WARNING_CAP = 200;
+    private static final AtomicLong heavyClipWarnings = new AtomicLong();
+    private static final int HEAVY_CLIP_WARNING_CAP = 30;
+    private static final double HEAVY_CLIP_RATIO = 0.5;
+    private static final int MIN_FOOTPRINT_CELLS_CHECKED = 3;
+    public static final java.util.concurrent.ConcurrentHashMap<String, AtomicLong> anchorYHisto = new java.util.concurrent.ConcurrentHashMap<>();
 
     public MantleFloatingObjectComponent(EngineMantle engineMantle) {
         super(engineMantle, ReservedFlag.FLOATING_OBJECT, 2);
     }
 
+    public static void resetObjectCounters() {
+        objectsAttempted.set(0);
+        objectsPlaced.set(0);
+        objectsSkippedNoFlat.set(0);
+        objectsSkippedNoInterior.set(0);
+        objectsRelaxed.set(0);
+        objectsSkippedShrink.set(0);
+        objectsSkippedNullObj.set(0);
+        terrainMismatchWarnings.set(0);
+        writesAttemptedTotal.set(0);
+        writesDroppedBelowTotal.set(0);
+        writesDroppedOverhangTotal.set(0);
+        heavyClipWarnings.set(0);
+        anchorYHisto.clear();
+    }
+
+    private static void recordWriteStats(IrisObject obj, int wx, int wz, int pickTopY, IslandObjectPlacer islandPlacer) {
+        int attempted = islandPlacer.getWritesAttempted();
+        int below = islandPlacer.getWritesDroppedBelow();
+        int overhang = islandPlacer.getWritesDroppedOverhang();
+        writesAttemptedTotal.addAndGet(attempted);
+        writesDroppedBelowTotal.addAndGet(below);
+        writesDroppedOverhangTotal.addAndGet(overhang);
+        int dropped = below + overhang;
+        if (attempted >= 32 && dropped >= attempted * HEAVY_CLIP_RATIO) {
+            long warned = heavyClipWarnings.get();
+            if (warned < HEAVY_CLIP_WARNING_CAP && heavyClipWarnings.incrementAndGet() <= HEAVY_CLIP_WARNING_CAP) {
+                String objKey = obj == null ? "<null>" : obj.getLoadKey();
+                Iris.warn("[FloatingWriteClip] object=" + objKey
+                        + " at=(" + wx + "," + (pickTopY + 1) + "," + wz + ")"
+                        + " attempted=" + attempted
+                        + " droppedBelow=" + below
+                        + " droppedOverhang=" + overhang
+                        + " written=" + (attempted - dropped));
+            }
+        }
+    }
+
+    private static void verifyTerrainBelowObject(MantleWriter writer, IrisObject obj, int wx, int wz, int pickTopY, FloatingIslandSample sample) {
+        long warned = terrainMismatchWarnings.get();
+        if (warned >= TERRAIN_MISMATCH_WARNING_CAP) {
+            return;
+        }
+        boolean mantleSolid;
+        try {
+            mantleSolid = writer.isSolid(wx, pickTopY, wz);
+        } catch (Throwable t) {
+            mantleSolid = false;
+        }
+        boolean sampleSolid = sample != null
+                && sample.solidMask != null
+                && sample.topIdx >= 0
+                && sample.topIdx < sample.solidMask.length
+                && sample.solidMask[sample.topIdx];
+        if (mantleSolid && sampleSolid) {
+            return;
+        }
+        if (terrainMismatchWarnings.incrementAndGet() > TERRAIN_MISMATCH_WARNING_CAP) {
+            return;
+        }
+        String objKey = obj == null ? "<null>" : obj.getLoadKey();
+        String sampleTop = sample == null ? "null" : String.valueOf(sample.topY());
+        String sampleBase = sample == null ? "null" : String.valueOf(sample.islandBaseY);
+        String sampleTopIdx = sample == null ? "null" : String.valueOf(sample.topIdx);
+        String sampleMaskLen = sample == null || sample.solidMask == null ? "null" : String.valueOf(sample.solidMask.length);
+        Iris.warn("[FloatingTerrainCheck] object=" + objKey
+                + " at=(" + wx + "," + (pickTopY + 1) + "," + wz + ")"
+                + " expected solid below at y=" + pickTopY
+                + " mantleSolid=" + mantleSolid
+                + " sampleSolid=" + sampleSolid
+                + " sampleTopY=" + sampleTop
+                + " sampleBaseY=" + sampleBase
+                + " sampleTopIdx=" + sampleTopIdx
+                + " sampleMaskLen=" + sampleMaskLen);
+    }
+
     @Override
     public void generateLayer(MantleWriter writer, int x, int z, ChunkContext context) {
         IrisComplex complex = context.getComplex();
@@ -68,7 +165,7 @@ public class MantleFloatingObjectComponent extends IrisMantleComponent {
                 if (parent == null || parent.getFloatingChildBiomes() == null || parent.getFloatingChildBiomes().isEmpty()) {
                     continue;
                 }
-                FloatingIslandSample sample = FloatingIslandSample.sampleMemoized(parent, wx, wz, chunkHeight, baseSeed, data, complex, getEngineMantle().getEngine());
+                FloatingIslandSample sample = FloatingIslandSample.sampleMemoized(parent, wx, wz, chunkHeight, baseSeed, data, getEngineMantle().getEngine());
                 if (sample != null) {
                     samples[(zf << 4) | xf] = sample;
                 }
@@ -103,14 +200,14 @@ public class MantleFloatingObjectComponent extends IrisMantleComponent {
 
             if (entry.isInheritObjects() && target != null) {
                 for (IrisObjectPlacement placement : target.getSurfaceObjects()) {
-                    tryPlaceAnchoredChunk(writer, complex, chunkRng, data, placement, samples, columns, minX, minZ, entry);
+                    tryPlaceAnchoredChunk(writer, complex, chunkRng, data, placement, samples, columns, minX, minZ, entry, target);
                 }
             }
 
             KList<IrisObjectPlacement> extras = entry.getExtraObjects();
             if (extras != null && !extras.isEmpty()) {
                 for (IrisObjectPlacement placement : extras) {
-                    tryPlaceAnchoredChunk(writer, complex, chunkRng, data, placement, samples, columns, minX, minZ, entry);
+                    tryPlaceAnchoredChunk(writer, complex, chunkRng, data, placement, samples, columns, minX, minZ, entry, target);
                 }
             }
         }
@@ -124,20 +221,24 @@ public class MantleFloatingObjectComponent extends IrisMantleComponent {
         int density = placement.getDensity(rng, minX, minZ, data);
         double perAttempt = placement.getChance();
         for (int i = 0; i < density; i++) {
+            objectsAttempted.incrementAndGet();
             if (!rng.chance(perAttempt + rng.d(-0.005, 0.005))) {
                 continue;
             }
             IrisObject raw = placement.getObject(complex, rng);
             if (raw == null) {
+                objectsSkippedNullObj.incrementAndGet();
                 continue;
             }
             IrisObject obj0 = placement.getScale().get(rng, raw);
             if (obj0 == null) {
+                objectsSkippedShrink.incrementAndGet();
                 continue;
             }
             if (entry != null && entry.hasObjectShrink()) {
                 obj0 = entry.getShrinkScale().get(rng, obj0);
                 if (obj0 == null) {
+                    objectsSkippedShrink.incrementAndGet();
                     continue;
                 }
             }
@@ -156,6 +257,7 @@ public class MantleFloatingObjectComponent extends IrisMantleComponent {
                         writer.setData(b.getX(), b.getY(), b.getZ(), marker);
                     }
                 }, null, data);
+                objectsPlaced.incrementAndGet();
             } catch (Throwable e) {
                 Iris.reportError(e);
             }
@@ -163,67 +265,138 @@ public class MantleFloatingObjectComponent extends IrisMantleComponent {
     }
 
     @ChunkCoordinates
-    private void tryPlaceAnchoredChunk(MantleWriter writer, IrisComplex complex, RNG rng, IrisData data, IrisObjectPlacement placement, FloatingIslandSample[] samples, KList<Integer> columns, int minX, int minZ, IrisFloatingChildBiomes entry) {
+    private void tryPlaceAnchoredChunk(MantleWriter writer, IrisComplex complex, RNG rng, IrisData data, IrisObjectPlacement placement, FloatingIslandSample[] samples, KList<Integer> columns, int minX, int minZ, IrisFloatingChildBiomes entry, IrisBiome target) {
         if (placement == null || columns.isEmpty()) {
             return;
         }
-        KList<Integer> interior = interiorColumns(samples, columns);
-        KList<Integer> pickPool = interior.isEmpty() ? columns : interior;
         int density = placement.getDensity(rng, minX, minZ, data);
         double perAttempt = placement.getChance();
+        KList<Integer> interior = interiorColumns(samples, columns);
+
         for (int i = 0; i < density; i++) {
+            objectsAttempted.incrementAndGet();
             if (!rng.chance(perAttempt + rng.d(-0.005, 0.005))) {
                 continue;
             }
+
             IrisObject raw = placement.getObject(complex, rng);
             if (raw == null) {
+                objectsSkippedNullObj.incrementAndGet();
                 continue;
             }
             IrisObject obj0 = placement.getScale().get(rng, raw);
             if (obj0 == null) {
+                objectsSkippedShrink.incrementAndGet();
                 continue;
             }
             if (entry != null && entry.hasObjectShrink()) {
                 obj0 = entry.getShrinkScale().get(rng, obj0);
                 if (obj0 == null) {
+                    objectsSkippedShrink.incrementAndGet();
                     continue;
                 }
             }
             final IrisObject obj = obj0;
 
-            int key = pickPool.get(rng.i(0, pickPool.size() - 1));
-            int xf = key & 15;
-            int zf = key >> 4;
-            FloatingIslandSample sample = samples[(zf << 4) | xf];
-            if (sample == null) {
+            FloatingObjectFootprint fp = FloatingObjectFootprint.compute(obj);
+
+            KList<Integer> pool = interior.isEmpty() ? columns : interior;
+            if (interior.isEmpty()) {
+                objectsSkippedNoInterior.incrementAndGet();
+            }
+
+            int pickedKey = pool.get(rng.i(0, pool.size() - 1));
+            int pickedXf = pickedKey & 15;
+            int pickedZf = pickedKey >> 4;
+            FloatingIslandSample pickedSample = samples[(pickedZf << 4) | pickedXf];
+            if (pickedSample == null) {
+                objectsSkippedNoFlat.incrementAndGet();
                 continue;
             }
-            int wx = minX + xf;
-            int wz = minZ + zf;
+            int pickTopY = pickedSample.topY();
 
-            int anchorY = sample.topY() + 1 + obj.getCenter().getBlockY();
-            int id = rng.i(0, Integer.MAX_VALUE);
+            if (!isFootprintFlat(fp, pickedXf, pickedZf, pickTopY, samples, 2)) {
+                if (!isFootprintFlat(fp, pickedXf, pickedZf, pickTopY, samples, 4)) {
+                    objectsSkippedNoFlat.incrementAndGet();
+                    continue;
+                }
+                objectsRelaxed.incrementAndGet();
+            }
+
+            int wx = minX + pickedXf - fp.getTallestKx();
+            int wz = minZ + pickedZf - fp.getTallestKz();
 
             IrisObjectPlacement anchored = placement.toPlacement(obj.getLoadKey());
-            anchored.setCarvingSupport(CarvingMode.ANYWHERE);
+            anchored.setMode(translateStiltModeForFloating(anchored.getMode()));
+            anchored.setTranslate(new IrisObjectTranslate());
+            anchored.setRotation(IrisObjectRotation.of(0, 0, 0));
             anchored.setForcePlace(true);
-            anchored.setMode(ObjectPlaceMode.STRUCTURE_PIECE);
-            anchored.setBore(false);
-            anchored.setMeld(false);
+            anchored.setBottom(false);
+
+            int yv = pickTopY + 1 - fp.getLowestSolidKeyY();
+
+            IslandObjectPlacer islandPlacer = new IslandObjectPlacer(writer, samples, minX, minZ, pickTopY);
+            int id = rng.i(0, Integer.MAX_VALUE);
 
             try {
-                obj.place(wx, anchorY, wz, writer, anchored, rng, (b, bd) -> {
+                obj.place(wx, yv, wz, islandPlacer, anchored, rng, (b, bd) -> {
                     String marker = placementMarker(obj, id);
                     if (marker != null) {
                         writer.setData(b.getX(), b.getY(), b.getZ(), marker);
                     }
                 }, null, data);
+                objectsPlaced.incrementAndGet();
+                recordAnchorYHisto(pickTopY);
+                int trunkWx = minX + pickedXf;
+                int trunkWz = minZ + pickedZf;
+                verifyTerrainBelowObject(writer, obj, trunkWx, trunkWz, pickTopY, pickedSample);
+                recordWriteStats(obj, trunkWx, trunkWz, pickTopY, islandPlacer);
             } catch (Throwable e) {
                 Iris.reportError(e);
             }
         }
     }
 
+    private static boolean isFootprintFlat(FloatingObjectFootprint fp, int pickedXf, int pickedZf, int pickTopY, FloatingIslandSample[] samples, int tolerance) {
+        int tallestKx = fp.getTallestKx();
+        int tallestKz = fp.getTallestKz();
+        int checked = 0;
+        boolean touchedChunkEdge = false;
+        for (long encoded : fp.footprintXZ()) {
+            int kx = (int) (encoded >> 32);
+            int kz = (int) (encoded & 0xFFFFFFFFL);
+            int colXf = pickedXf + (kx - tallestKx);
+            int colZf = pickedZf + (kz - tallestKz);
+            if (colXf < 0 || colXf >= 16 || colZf < 0 || colZf >= 16) {
+                touchedChunkEdge = true;
+                continue;
+            }
+            FloatingIslandSample s = samples[(colZf << 4) | colXf];
+            if (s == null || Math.abs(s.topY() - pickTopY) > tolerance) {
+                return false;
+            }
+            checked++;
+        }
+        if (checked >= MIN_FOOTPRINT_CELLS_CHECKED) {
+            return true;
+        }
+        return touchedChunkEdge;
+    }
+
+    private static void recordAnchorYHisto(int topY) {
+        String bucket = String.valueOf(topY >> 3);
+        if (anchorYHisto.size() < 32) {
+            anchorYHisto.computeIfAbsent(bucket, k -> new AtomicLong()).incrementAndGet();
+        } else {
+            AtomicLong existing = anchorYHisto.get(bucket);
+            if (existing != null) {
+                existing.incrementAndGet();
+            } else {
+                anchorYHisto.computeIfAbsent("other", k -> new AtomicLong()).incrementAndGet();
+            }
+        }
+    }
+
     private static KList<Integer> interiorColumns(FloatingIslandSample[] samples, KList<Integer> columns) {
         KList<Integer> interior = new KList<>();
         for (int key : columns) {
@@ -252,23 +425,64 @@ public class MantleFloatingObjectComponent extends IrisMantleComponent {
         return key + "@" + id;
     }
 
+    private static ObjectPlaceMode translateStiltModeForFloating(ObjectPlaceMode m) {
+        return switch (m) {
+            case STILT -> ObjectPlaceMode.MAX_HEIGHT;
+            case FAST_STILT -> ObjectPlaceMode.FAST_MAX_HEIGHT;
+            case MIN_STILT -> ObjectPlaceMode.MIN_HEIGHT;
+            case FAST_MIN_STILT -> ObjectPlaceMode.FAST_MIN_HEIGHT;
+            case CENTER_STILT -> ObjectPlaceMode.CENTER_HEIGHT;
+            case ERODE_STILT -> ObjectPlaceMode.MAX_HEIGHT;
+            case STRUCTURE_PIECE -> ObjectPlaceMode.CENTER_HEIGHT;
+            default -> m;
+        };
+    }
+
     @Override
     protected int computeRadius() {
-        int maxThickness = 0;
-        int maxHeightAbove = 0;
+        int maxObjectExtent = 0;
+        java.util.Set<String> objectKeys = new java.util.HashSet<>();
         try {
+            IrisData data = getData();
             for (IrisBiome biome : getDimension().getAllBiomes(this::getData)) {
                 KList<IrisFloatingChildBiomes> entries = biome.getFloatingChildBiomes();
                 if (entries == null || entries.isEmpty()) {
                     continue;
                 }
                 for (IrisFloatingChildBiomes entry : entries) {
-                    maxThickness = Math.max(maxThickness, entry.getMaxThickness());
-                    maxHeightAbove = Math.max(maxHeightAbove, entry.getMaxHeightAboveSurface());
+                    collectPlacementKeys(entry.getFloatingObjects(), objectKeys);
+                    collectPlacementKeys(entry.getExtraObjects(), objectKeys);
+                    if (entry.isInheritObjects()) {
+                        try {
+                            IrisBiome target = entry.getRealBiome(biome, data);
+                            if (target != null) {
+                                collectPlacementKeys(target.getSurfaceObjects(), objectKeys);
+                            }
+                        } catch (Throwable ignored) {
+                        }
+                    }
+                }
+            }
+            for (String key : objectKeys) {
+                try {
+                    java.io.File f = data.getObjectLoader().findFile(key);
+                    if (f == null) continue;
+                    org.bukkit.util.BlockVector sz = IrisObject.sampleSize(f);
+                    int extent = Math.max(sz.getBlockX(), sz.getBlockZ());
+                    if (extent > maxObjectExtent) maxObjectExtent = extent;
+                } catch (Throwable ignored) {
                 }
             }
         } catch (Throwable ignored) {
         }
-        return Math.max(1, (maxThickness + maxHeightAbove) >> 4);
+        return Math.max(16, maxObjectExtent);
+    }
+
+    private static void collectPlacementKeys(KList<IrisObjectPlacement> placements, java.util.Set<String> out) {
+        if (placements == null) return;
+        for (IrisObjectPlacement p : placements) {
+            if (p == null || p.getPlace() == null) continue;
+            out.addAll(p.getPlace());
+        }
     }
 }

core/src/main/java/art/arcane/iris/engine/modifier/IrisFloatingChildBiomeModifier.java

@@ -21,15 +21,17 @@ package art.arcane.iris.engine.modifier;
 import art.arcane.iris.core.loader.IrisData;
 import art.arcane.iris.core.nms.INMS;
 import art.arcane.iris.engine.IrisComplex;
-import art.arcane.iris.engine.decorator.IrisFloatingSurfaceDecorator;
+import art.arcane.iris.engine.decorator.FloatingDecorator;
 import art.arcane.iris.engine.decorator.IrisSeaSurfaceDecorator;
 import static art.arcane.iris.engine.mantle.EngineMantle.AIR;
 import art.arcane.iris.engine.framework.Engine;
 import art.arcane.iris.engine.framework.EngineAssignedModifier;
 import art.arcane.iris.engine.framework.EngineDecorator;
+import art.arcane.iris.engine.mantle.components.MantleFloatingObjectComponent;
 import art.arcane.iris.engine.object.FloatingIslandSample;
 import art.arcane.iris.engine.object.IrisBiome;
 import art.arcane.iris.engine.object.IrisBiomeCustom;
+import art.arcane.iris.engine.object.IrisDecorationPart;
 import art.arcane.iris.engine.object.IrisDimension;
 import art.arcane.iris.engine.object.IrisFloatingChildBiomes;
 import art.arcane.iris.util.common.data.B;
@@ -43,21 +45,23 @@ import art.arcane.volmlib.util.scheduling.PrecisionStopwatch;
 import org.bukkit.block.Biome;
 import org.bukkit.block.data.BlockData;
 
+import java.util.concurrent.atomic.AtomicLong;
+
 public class IrisFloatingChildBiomeModifier extends EngineAssignedModifier<BlockData> {
     public static final long FLOATING_BASE_SEED_SALT = 0x5EED_F107_00F1B10CL;
-    private static final java.util.concurrent.atomic.AtomicLong columnsChecked = new java.util.concurrent.atomic.AtomicLong();
-    private static final java.util.concurrent.atomic.AtomicLong samplesAccepted = new java.util.concurrent.atomic.AtomicLong();
-    private static final java.util.concurrent.atomic.AtomicLong decorateInvocations = new java.util.concurrent.atomic.AtomicLong();
-    private static final java.util.concurrent.atomic.AtomicLong decorateSkippedNotAir = new java.util.concurrent.atomic.AtomicLong();
-    private static final java.util.concurrent.atomic.AtomicLong decorateSkippedNoInherit = new java.util.concurrent.atomic.AtomicLong();
-    private static final java.util.concurrent.atomic.AtomicLong decoratePhaseColumns = new java.util.concurrent.atomic.AtomicLong();
-    private static final java.util.concurrent.atomic.AtomicLong decoratePlaced = new java.util.concurrent.atomic.AtomicLong();
-    private static final java.util.concurrent.atomic.AtomicLong decorateNoChange = new java.util.concurrent.atomic.AtomicLong();
-    private static final java.util.concurrent.atomic.AtomicLong decorateFloorNull = new java.util.concurrent.atomic.AtomicLong();
-    private static final java.util.concurrent.ConcurrentHashMap<String, java.util.concurrent.atomic.AtomicLong> floorMatHisto = new java.util.concurrent.ConcurrentHashMap<>();
-    private static final java.util.concurrent.atomic.AtomicLong lastReportMs = new java.util.concurrent.atomic.AtomicLong(0L);
+    private static final AtomicLong columnsChecked = new AtomicLong();
+    private static final AtomicLong samplesAccepted = new AtomicLong();
+    private static final AtomicLong decorateInvocations = new AtomicLong();
+    private static final AtomicLong decorateSkippedNotAir = new AtomicLong();
+    private static final AtomicLong decorateSkippedNoInherit = new AtomicLong();
+    private static final AtomicLong decoratePhaseColumns = new AtomicLong();
+    private static final AtomicLong decoratePlaced = new AtomicLong();
+    private static final AtomicLong decorateNoChange = new AtomicLong();
+    private static final AtomicLong decorateFloorNull = new AtomicLong();
+    private static final java.util.concurrent.ConcurrentHashMap<String, AtomicLong> floorMatHisto = new java.util.concurrent.ConcurrentHashMap<>();
+    private static final AtomicLong lastReportMs = new AtomicLong(0L);
+    private static final AtomicLong reportCycle = new AtomicLong(0L);
     private final RNG rng;
-    private final EngineDecorator surfaceDecorator;
     private final EngineDecorator seaSurfaceDecorator;
 
     public static void reportFloatingStats() {
@@ -66,15 +70,36 @@ public class IrisFloatingChildBiomeModifier extends EngineAssignedModifier<Block
                 .sorted((a, b) -> Long.compare(b.getValue().get(), a.getValue().get()))
                 .limit(5)
                 .forEach(e -> topFloors.append(' ').append(e.getKey()).append('=').append(e.getValue().get()));
-        art.arcane.iris.Iris.info("[floating-debug] columns=" + columnsChecked.get()
+
+        StringBuilder topAnchorY = new StringBuilder();
+        MantleFloatingObjectComponent.anchorYHisto.entrySet().stream()
+                .sorted((a, b) -> Long.compare(b.getValue().get(), a.getValue().get()))
+                .limit(5)
+                .forEach(e -> topAnchorY.append(' ').append(e.getKey()).append('=').append(e.getValue().get()));
+
+        art.arcane.iris.Iris.info("[floating-debug]"
+                + " columns=" + columnsChecked.get()
                 + " samples=" + samplesAccepted.get()
                 + " decInvoke=" + decorateInvocations.get()
                 + " decPlaced=" + decoratePlaced.get()
                 + " decNoChange=" + decorateNoChange.get()
                 + " decFloorNull=" + decorateFloorNull.get()
+                + " decCandidatesNull=" + FloatingDecorator.decCandidatesNull.get()
                 + " decSkipNonAir=" + decorateSkippedNotAir.get()
                 + " decSkipNoInherit=" + decorateSkippedNoInherit.get()
                 + " decPhaseCols=" + decoratePhaseColumns.get()
+                + " objAttempt=" + MantleFloatingObjectComponent.objectsAttempted.get()
+                + " objPlaced=" + MantleFloatingObjectComponent.objectsPlaced.get()
+                + " objNoFlat=" + MantleFloatingObjectComponent.objectsSkippedNoFlat.get()
+                + " objNoInterior=" + MantleFloatingObjectComponent.objectsSkippedNoInterior.get()
+                + " objRelax=" + MantleFloatingObjectComponent.objectsRelaxed.get()
+                + " objShrinkDrop=" + MantleFloatingObjectComponent.objectsSkippedShrink.get()
+                + " objNullObj=" + MantleFloatingObjectComponent.objectsSkippedNullObj.get()
+                + " writeAttempt=" + MantleFloatingObjectComponent.writesAttemptedTotal.get()
+                + " writeDropBelow=" + MantleFloatingObjectComponent.writesDroppedBelowTotal.get()
+                + " writeDropOverhang=" + MantleFloatingObjectComponent.writesDroppedOverhangTotal.get()
+                + " terrainMismatch=" + MantleFloatingObjectComponent.terrainMismatchWarnings.get()
+                + " anchorY:" + (topAnchorY.length() == 0 ? " <none>" : topAnchorY.toString())
                 + " topFloors:" + (topFloors.length() == 0 ? " <none>" : topFloors.toString()));
     }
 
@@ -83,13 +108,44 @@ public class IrisFloatingChildBiomeModifier extends EngineAssignedModifier<Block
         long last = lastReportMs.get();
         if (now - last >= 10000L && lastReportMs.compareAndSet(last, now)) {
             reportFloatingStats();
+            if (reportCycle.incrementAndGet() >= 30) {
+                reportCycle.set(0);
+                resetAllCounters();
+            }
+        }
+    }
+
+    private static void resetAllCounters() {
+        columnsChecked.set(0);
+        samplesAccepted.set(0);
+        decorateInvocations.set(0);
+        decorateSkippedNotAir.set(0);
+        decorateSkippedNoInherit.set(0);
+        decoratePhaseColumns.set(0);
+        decoratePlaced.set(0);
+        decorateNoChange.set(0);
+        decorateFloorNull.set(0);
+        floorMatHisto.clear();
+        FloatingDecorator.decCandidatesNull.set(0);
+        MantleFloatingObjectComponent.resetObjectCounters();
+    }
+
+    private static void recordFloorMat(String matKey) {
+        if (floorMatHisto.size() < 32) {
+            floorMatHisto.computeIfAbsent(matKey, k -> new AtomicLong()).incrementAndGet();
+        } else {
+            AtomicLong existing = floorMatHisto.get(matKey);
+            if (existing != null) {
+                existing.incrementAndGet();
+            } else {
+                floorMatHisto.computeIfAbsent("other", k -> new AtomicLong()).incrementAndGet();
+            }
         }
     }
 
     public IrisFloatingChildBiomeModifier(Engine engine) {
         super(engine, "FloatingChildBiomes");
         rng = new RNG(engine.getSeedManager().getTerrain() ^ 0x7EB0A73F1DCE514DL);
-        surfaceDecorator = new IrisFloatingSurfaceDecorator(engine);
         seaSurfaceDecorator = new IrisSeaSurfaceDecorator(engine);
     }
 
@@ -112,7 +168,7 @@ public class IrisFloatingChildBiomeModifier extends EngineAssignedModifier<Block
                 }
                 columnsChecked.incrementAndGet();
 
-                FloatingIslandSample sample = FloatingIslandSample.sampleMemoized(parent, wx, wz, chunkHeight, baseSeed, data, complex, getEngine());
+                FloatingIslandSample sample = FloatingIslandSample.sampleMemoized(parent, wx, wz, chunkHeight, baseSeed, data, getEngine());
                 if (sample == null) {
                     continue;
                 }
@@ -202,7 +258,7 @@ public class IrisFloatingChildBiomeModifier extends EngineAssignedModifier<Block
                 if (parent == null || parent.getFloatingChildBiomes() == null || parent.getFloatingChildBiomes().isEmpty()) {
                     continue;
                 }
-                FloatingIslandSample sample = FloatingIslandSample.sampleMemoized(parent, wx, wz, chunkHeight, baseSeed, data, complex, getEngine());
+                FloatingIslandSample sample = FloatingIslandSample.sampleMemoized(parent, wx, wz, chunkHeight, baseSeed, data, getEngine());
                 if (sample == null) {
                     continue;
                 }
@@ -225,20 +281,19 @@ public class IrisFloatingChildBiomeModifier extends EngineAssignedModifier<Block
                         if (floor == null) {
                             decorateFloorNull.incrementAndGet();
                         } else {
-                            String matKey = floor.getMaterial().getKey().getKey();
-                            floorMatHisto.computeIfAbsent(matKey, k -> new java.util.concurrent.atomic.AtomicLong()).incrementAndGet();
+                            recordFloorMat(floor.getMaterial().getKey().getKey());
                         }
                         try {
-                            surfaceDecorator.decorate(xf, zf, wx, wz, output, target, topY, max);
+                            RNG colRng = rng.nextParallelRNG((int) FloatingIslandSample.columnSeed(baseSeed, wx, wz));
+                            int placed = FloatingDecorator.decorateColumn(getEngine(), target, IrisDecorationPart.NONE, xf, zf, wx, wz, topY, max, output, colRng);
+                            if (placed > 0) {
+                                decoratePlaced.addAndGet(placed);
+                            } else {
+                                decorateNoChange.incrementAndGet();
+                            }
                         } catch (Throwable e) {
                             art.arcane.iris.Iris.reportError(e);
                         }
-                        BlockData afterAbove = output.get(xf, topY + 1, zf);
-                        if (afterAbove != null && !B.isAir(afterAbove)) {
-                            decoratePlaced.incrementAndGet();
-                        } else {
-                            decorateNoChange.incrementAndGet();
-                        }
                     } else {
                         decorateSkippedNotAir.incrementAndGet();
                     }
@@ -269,10 +324,7 @@ public class IrisFloatingChildBiomeModifier extends EngineAssignedModifier<Block
                     }
                     if (fluidTopY > 0 && fluidTopY + 1 < chunkHeight && B.isAir(output.get(xf, fluidTopY + 1, zf))) {
                         try {
-                            seaSurfaceDecorator.decorate(xf, zf,
-                                    wx, wx + 1, wx - 1,
-                                    wz, wz + 1, wz - 1,
-                                    output, target, fluidTopY, chunkHeight);
+                            seaSurfaceDecorator.decorate(xf, zf, wx, wx + 1, wx - 1, wz, wz + 1, wz - 1, output, target, fluidTopY, chunkHeight);
                         } catch (Throwable e) {
                             art.arcane.iris.Iris.reportError(e);
                         }

core/src/main/java/art/arcane/iris/engine/object/FloatingIslandSample.java

@@ -20,7 +20,6 @@ package art.arcane.iris.engine.object;
 
 import art.arcane.iris.Iris;
 import art.arcane.iris.core.loader.IrisData;
-import art.arcane.iris.engine.IrisComplex;
 import art.arcane.iris.engine.framework.Engine;
 import art.arcane.iris.util.project.noise.CNG;
 import art.arcane.volmlib.util.collection.KList;
@@ -63,13 +62,13 @@ public final class FloatingIslandSample {
         CHUNK_MEMO.get().clear();
     }
 
-    public static FloatingIslandSample sampleMemoized(IrisBiome parent, int wx, int wz, int chunkHeight, long baseSeed, IrisData data, IrisComplex complex, Engine engine) {
+    public static FloatingIslandSample sampleMemoized(IrisBiome parent, int wx, int wz, int chunkHeight, long baseSeed, IrisData data, Engine engine) {
         long key = (((long) wx) << 32) ^ (wz & 0xFFFFFFFFL);
         HashMap<Long, FloatingIslandSample> memo = CHUNK_MEMO.get();
         if (memo.containsKey(key)) {
             return memo.get(key);
         }
-        FloatingIslandSample result = sample(parent, wx, wz, chunkHeight, baseSeed, data, complex, engine);
+        FloatingIslandSample result = sample(parent, wx, wz, chunkHeight, baseSeed, data, engine);
         memo.put(key, result);
         return result;
     }
@@ -111,7 +110,7 @@ public final class FloatingIslandSample {
         return baseSeed ^ ((long) wx * 341873128712L) ^ ((long) wz * 132897987541L);
     }
 
-    public static FloatingIslandSample sample(IrisBiome parent, int wx, int wz, int chunkHeight, long baseSeed, IrisData data, IrisComplex complex, Engine engine) {
+    public static FloatingIslandSample sample(IrisBiome parent, int wx, int wz, int chunkHeight, long baseSeed, IrisData data, Engine engine) {
         KList<IrisFloatingChildBiomes> entries = parent.getFloatingChildBiomes();
         if (entries == null || entries.isEmpty()) {
             return reject(REJECT_NO_ENTRIES);
@@ -153,8 +152,6 @@ public final class FloatingIslandSample {
             return reject(REJECT_NO_SEED);
         }
 
-        int surfaceY = (int) Math.round(complex.getHeightStream().get(wx & ~63, wz & ~63));
-
         CNG altitudeCng = entry.getAltitudeCng(baseSeed, data);
         if (altitudeCng == null) {
             warnNullCng("altitudeStyle", parent);
@@ -162,9 +159,10 @@ public final class FloatingIslandSample {
         }
         double altNoise = altitudeCng.noise(wx, wz);
         double altClamped = Math.max(0, Math.min(1, altNoise));
-        int minAlt = Math.max(0, entry.getMinHeightAboveSurface());
-        int maxAlt = Math.max(minAlt, entry.getMaxHeightAboveSurface());
-        int baseY = surfaceY + minAlt + (int) Math.round(altClamped * (maxAlt - minAlt));
+        int worldMin = engine.getWorld().minHeight();
+        int minAlt = Math.max(0, entry.getMinHeightAboveSurface() - worldMin);
+        int maxAlt = Math.max(minAlt, entry.getMaxHeightAboveSurface() - worldMin);
+        int baseY = minAlt + (int) Math.round(altClamped * (maxAlt - minAlt));
 
         IrisBiome target = entry.getRealBiome(parent, data);
         int topH = computeTopHeight(entry, target, engine, baseSeed, wx, wz, data);
@@ -188,12 +186,12 @@ public final class FloatingIslandSample {
         int botY = baseY - depth;
 
         Integer minAbsoluteY = entry.getMinAbsoluteY();
-        if (minAbsoluteY != null && botY < minAbsoluteY) {
-            botY = minAbsoluteY;
+        if (minAbsoluteY != null && botY < minAbsoluteY - worldMin) {
+            botY = minAbsoluteY - worldMin;
         }
         Integer maxAbsoluteY = entry.getMaxAbsoluteY();
-        if (maxAbsoluteY != null && topY > maxAbsoluteY) {
-            topY = maxAbsoluteY;
+        if (maxAbsoluteY != null && topY > maxAbsoluteY - worldMin) {
+            topY = maxAbsoluteY - worldMin;
         }
 
         if (botY < 0) {

core/src/main/java/art/arcane/iris/engine/object/FloatingObjectFootprint.java

@@ -0,0 +1,242 @@
+/*
+ * Iris is a World Generator for Minecraft Bukkit Servers
+ * Copyright (c) 2022 Arcane Arts (Volmit Software)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package art.arcane.iris.engine.object;
+
+import art.arcane.iris.Iris;
+import art.arcane.iris.util.common.data.B;
+import org.bukkit.block.data.BlockData;
+import org.bukkit.util.BlockVector;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class FloatingObjectFootprint {
+    private static final ConcurrentHashMap<String, FloatingObjectFootprint> CACHE = new ConcurrentHashMap<>();
+    private static final boolean DIAGNOSTIC_LOG = Boolean.parseBoolean(System.getProperty("iris.floating.footprintLog", "true"));
+
+    private final int lowestSolidKeyY;
+    private final int centerX;
+    private final int centerY;
+    private final int centerZ;
+    private final int tallestKx;
+    private final int tallestKz;
+    private final Set<Long> footprintXZ;
+
+    private FloatingObjectFootprint(int lowestSolidKeyY, int centerX, int centerY, int centerZ, int tallestKx, int tallestKz, Set<Long> footprintXZ) {
+        this.lowestSolidKeyY = lowestSolidKeyY;
+        this.centerX = centerX;
+        this.centerY = centerY;
+        this.centerZ = centerZ;
+        this.tallestKx = tallestKx;
+        this.tallestKz = tallestKz;
+        this.footprintXZ = Collections.unmodifiableSet(footprintXZ);
+    }
+
+    public static FloatingObjectFootprint compute(IrisObject obj) {
+        String cacheKey = obj.getLoadKey() + "@" + obj.getW() + "x" + obj.getH() + "x" + obj.getD();
+        return CACHE.computeIfAbsent(cacheKey, k -> doCompute(obj, k));
+    }
+
+    private static FloatingObjectFootprint doCompute(IrisObject obj, String cacheKey) {
+        int cx = obj.getCenter().getBlockX();
+        int cy = obj.getCenter().getBlockY();
+        int cz = obj.getCenter().getBlockZ();
+        Set<Long> xzSet = new HashSet<>();
+        Map<Long, int[]> columnStats = new HashMap<>();
+
+        obj.getBlocks().forEach((BlockVector key, BlockData bd) -> {
+            if (!B.isSolid(bd)) {
+                return;
+            }
+            int kx = key.getBlockX();
+            int ky = key.getBlockY();
+            int kz = key.getBlockZ();
+            long packed = ((long) kx << 32) | (kz & 0xFFFFFFFFL);
+            xzSet.add(packed);
+            int[] stats = columnStats.get(packed);
+            if (stats == null) {
+                stats = new int[]{ky, 1};
+                columnStats.put(packed, stats);
+            } else {
+                if (ky < stats[0]) {
+                    stats[0] = ky;
+                }
+                stats[1]++;
+            }
+        });
+
+        long tallestPacked = resolveTallestColumn(columnStats);
+        int lowestSolidKeyY = columnStats.isEmpty()
+                ? cy
+                : columnStats.get(tallestPacked)[0];
+        int tallestKx = columnStats.isEmpty() ? 0 : (int) (tallestPacked >> 32);
+        int tallestKz = columnStats.isEmpty() ? 0 : (int) (tallestPacked & 0xFFFFFFFFL);
+        if (DIAGNOSTIC_LOG) {
+            logFootprintDiagnostic(cacheKey, obj, cx, cy, cz, lowestSolidKeyY, tallestKx, tallestKz, columnStats);
+        }
+        return new FloatingObjectFootprint(lowestSolidKeyY, cx, cy, cz, tallestKx, tallestKz, xzSet);
+    }
+
+    private static void logFootprintDiagnostic(String cacheKey, IrisObject obj, int cx, int cy, int cz, int anchorY, int tallestKx, int tallestKz, Map<Long, int[]> columnStats) {
+        if (columnStats.isEmpty()) {
+            Iris.info("[FloatingFootprint] key=" + cacheKey + " center=(" + cx + "," + cy + "," + cz + ") anchor=" + anchorY + " columns=0 (EMPTY)");
+            return;
+        }
+
+        int tallestCount = 0;
+        int tallestLow = Integer.MAX_VALUE;
+        int floorLow = Integer.MAX_VALUE;
+        int ceilingLow = Integer.MIN_VALUE;
+        int minKx = Integer.MAX_VALUE, maxKx = Integer.MIN_VALUE;
+        int minKz = Integer.MAX_VALUE, maxKz = Integer.MIN_VALUE;
+        TreeMap<Integer, Integer> lowYHisto = new TreeMap<>();
+        for (Map.Entry<Long, int[]> e : columnStats.entrySet()) {
+            long packed = e.getKey();
+            int kx = (int) (packed >> 32);
+            int kz = (int) (packed & 0xFFFFFFFFL);
+            if (kx < minKx) minKx = kx;
+            if (kx > maxKx) maxKx = kx;
+            if (kz < minKz) minKz = kz;
+            if (kz > maxKz) maxKz = kz;
+            int[] s = e.getValue();
+            int count = s[1];
+            int low = s[0];
+            if (count > tallestCount || (count == tallestCount && low < tallestLow)) {
+                tallestCount = count;
+                tallestLow = low;
+            }
+            if (low < floorLow) floorLow = low;
+            if (low > ceilingLow) ceilingLow = low;
+            lowYHisto.merge(low, 1, Integer::sum);
+        }
+
+        int straysBelowAnchor = 0;
+        for (int[] s : columnStats.values()) {
+            if (s[0] < anchorY) straysBelowAnchor++;
+        }
+
+        List<Map.Entry<Long, int[]>> sorted = new ArrayList<>(columnStats.entrySet());
+        sorted.sort((a, b) -> {
+            int cmp = Integer.compare(b.getValue()[1], a.getValue()[1]);
+            if (cmp != 0) return cmp;
+            return Integer.compare(a.getValue()[0], b.getValue()[0]);
+        });
+        StringBuilder topN = new StringBuilder();
+        int showN = Math.min(4, sorted.size());
+        for (int i = 0; i < showN; i++) {
+            Map.Entry<Long, int[]> e = sorted.get(i);
+            int kx = (int) (e.getKey() >> 32);
+            int kz = (int) (e.getKey() & 0xFFFFFFFFL);
+            int[] s = e.getValue();
+            if (i > 0) topN.append(",");
+            topN.append("(").append(kx).append(",").append(kz).append(")c=").append(s[1]).append(":y=").append(s[0]);
+        }
+
+        StringBuilder histo = new StringBuilder();
+        int histoEntries = 0;
+        for (Map.Entry<Integer, Integer> e : lowYHisto.entrySet()) {
+            if (histoEntries++ > 0) histo.append(",");
+            histo.append(e.getKey()).append("=").append(e.getValue());
+            if (histoEntries >= 6) {
+                if (lowYHisto.size() > 6) histo.append(",...+").append(lowYHisto.size() - 6);
+                break;
+            }
+        }
+
+        String keyStyle = (minKx >= 0 && minKz >= 0) ? "RAW" : "SIGNED";
+
+        Iris.info("[FloatingFootprint] key=" + cacheKey
+                + " dims=" + obj.getW() + "x" + obj.getH() + "x" + obj.getD()
+                + " center=(" + cx + "," + cy + "," + cz + ")"
+                + " keyStyle=" + keyStyle
+                + " kxRange=[" + minKx + "," + maxKx + "]"
+                + " kzRange=[" + minKz + "," + maxKz + "]"
+                + " cols=" + columnStats.size()
+                + " anchor=" + anchorY
+                + " relAnchor=" + (anchorY - cy)
+                + " tallestKxKz=(" + tallestKx + "," + tallestKz + ")"
+                + " floorLow=" + floorLow
+                + " ceilingLow=" + ceilingLow
+                + " tallest=count" + tallestCount + ":y" + tallestLow
+                + " straysBelow=" + straysBelowAnchor
+                + " topCols=[" + topN + "]"
+                + " lowYHisto={" + histo + "}");
+    }
+
+    private static long resolveTallestColumn(Map<Long, int[]> columnStats) {
+        long bestPacked = 0L;
+        int tallestCount = 0;
+        int tallestLow = Integer.MAX_VALUE;
+        for (Map.Entry<Long, int[]> e : columnStats.entrySet()) {
+            int[] stats = e.getValue();
+            int count = stats[1];
+            int low = stats[0];
+            if (count > tallestCount || (count == tallestCount && low < tallestLow)) {
+                tallestCount = count;
+                tallestLow = low;
+                bestPacked = e.getKey();
+            }
+        }
+        return bestPacked;
+    }
+
+    public boolean columnInFootprint(int objKeyX, int objKeyZ) {
+        return footprintXZ.contains(((long) objKeyX << 32) | (objKeyZ & 0xFFFFFFFFL));
+    }
+
+    public int lowestSolidRelCenterY() {
+        return lowestSolidKeyY - centerY;
+    }
+
+    public int getLowestSolidKeyY() {
+        return lowestSolidKeyY;
+    }
+
+    public int getCenterX() {
+        return centerX;
+    }
+
+    public int getCenterY() {
+        return centerY;
+    }
+
+    public int getCenterZ() {
+        return centerZ;
+    }
+
+    public int getTallestKx() {
+        return tallestKx;
+    }
+
+    public int getTallestKz() {
+        return tallestKz;
+    }
+
+    public Set<Long> footprintXZ() {
+        return footprintXZ;
+    }
+}

core/src/main/java/art/arcane/iris/engine/object/IrisFloatingChildBiomes.java

@@ -114,13 +114,13 @@ public class IrisFloatingChildBiomes implements IRare {
 
     @MinNumber(0)
     @MaxNumber(2032)
-    @Desc("Minimum blocks above the parent biome surface where the island base can sit.")
-    private int minHeightAboveSurface = 60;
+    @Desc("Minimum absolute world Y where the island base can sit. Island altitude is independent of the parent biome's terrain height; altitudeStyle noise varies the base between min and max per column.")
+    private int minHeightAboveSurface = 160;
 
     @MinNumber(0)
     @MaxNumber(2032)
-    @Desc("Maximum blocks above the parent biome surface where the island base can sit.")
-    private int maxHeightAboveSurface = 110;
+    @Desc("Maximum absolute world Y where the island base can sit. Island altitude is independent of the parent biome's terrain height; altitudeStyle noise varies the base between min and max per column.")
+    private int maxHeightAboveSurface = 210;
 
     @Desc("Optional absolute minimum world Y for the island base. When set, baseY is clamped upward so the tail bottom stays above this value.")
     private Integer minAbsoluteY = null;