Simplified procedural feature generation

- Fungi build stem roles directly without intermediate maps or coordinate arrays
- Tree palettes reuse one random source per object
- Persistent leaves skip distance traversal when plausibility is disabled
- Tree support scans avoid copied coordinate sets
- Coral arm samples reuse their endpoint array
- Sea decorators share scaled stack limits and respect output bounds
- Unresolved sea floor palette entries preserve existing water
- Tests cover stem geometry persistent leaves and sea stack limits

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

@@ -474,7 +474,7 @@ final class DecoratorCore {
                 && (!caveSkipFluid || !B.isFluid(lower) && !B.isFluid(upper));
     }
 
-    private static int computeStack(IrisDecorator decorator, RNG rng, double realX, double realZ,
+    static int computeStack(IrisDecorator decorator, RNG rng, double realX, double realZ,
                                     IrisData irisData, int max) {
         int stack = decorator.getHeight(rng, realX, realZ, irisData);
         if (decorator.isScaleStack()) {

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

@@ -39,6 +39,10 @@ public class IrisSeaFloorDecorator extends IrisEngineDecorator {
     @Override
     public void decorate(int x, int z, int realX, int realX1, int realX_1, int realZ, int realZ1, int realZ_1,
                          Hunk<PlatformBlockState> data, IrisBiome biome, int height, int max) {
+        int limit = Math.min(max, Math.min(getEngine().getHeight(), data.getHeight()));
+        if (height < 0 || height >= limit) {
+            return;
+        }
         RNG rng = getRNG(realX, realZ);
         IrisDecorator decorator = DecoratorCore.pickDecorator(biome, getPart(), partRNG, rng, getData(), realX, realZ);
 
@@ -51,34 +55,25 @@ public class IrisSeaFloorDecorator extends IrisEngineDecorator {
                     && !decorator.getSlopeCondition().isValid(getComplex().getSlopeStream().get(realX, realZ))) {
                 return;
             }
-            if (height >= 0 && height < getEngine().getHeight()) {
-                data.set(x, height, z, decorator.getBlockData100(biome, rng, realX, height, realZ, getData()));
+            PlatformBlockState block = decorator.getBlockData100(biome, rng, realX, height, realZ, getData());
+            if (block != null) {
+                data.set(x, height, z, block);
             }
             return;
         }
 
-        int stack = decorator.getHeight(rng, realX, realZ, getData());
-        if (decorator.isScaleStack()) {
-            stack = (int) Math.ceil((double) (max - height) * ((double) stack / 100));
-        } else {
-            stack = Math.min(stack, max - height);
-        }
-
-        if (stack == 1) {
-            data.set(x, height, z, decorator.getBlockDataForTop(biome, rng, realX, height, realZ, getData()));
-            return;
-        }
-
-        int engineHeight = getEngine().getHeight();
+        int stack = Math.min(limit - height,
+                DecoratorCore.computeStack(decorator, rng, realX, realZ, getData(), max - height));
         for (int i = 0; i < stack; i++) {
             int h = height + i;
-            if (h > max || h > engineHeight) {
-                continue;
-            }
-            double threshold = ((double) i) / (stack - 1);
-            data.set(x, h, z, threshold >= decorator.getTopThreshold()
+            double threshold = stack == 1 ? 1.0 : ((double) i) / (stack - 1);
+            PlatformBlockState block = threshold >= decorator.getTopThreshold()
                     ? decorator.getBlockDataForTop(biome, rng, realX, h, realZ, getData())
-                    : decorator.getBlockData100(biome, rng, realX, h, realZ, getData()));
+                    : decorator.getBlockData100(biome, rng, realX, h, realZ, getData());
+            if (block == null) {
+                break;
+            }
+            data.set(x, h, z, block);
         }
     }
 }

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

@@ -58,10 +58,7 @@ public class IrisSeaSurfaceDecorator extends IrisEngineDecorator {
             return;
         }
 
-        int stack = decorator.getHeight(rng, realX, realZ, getData());
-        if (decorator.isScaleStack()) {
-            stack = (int) Math.ceil((double) (max - height) * ((double) stack / 100));
-        }
+        int stack = DecoratorCore.computeStack(decorator, rng, realX, realZ, getData(), max - height);
 
         if (stack == 1) {
             int targetY = height + 1;

core/src/main/java/art/arcane/iris/engine/object/coral/CoralGenerator.java

@@ -170,7 +170,9 @@ public final class CoralGenerator {
             int y = (int) Math.round(oy + dy * t);
             int z = (int) Math.round(oz + dz * t - sway);
             canvas.set(x, y, z, CoralCanvas.Role.STRUCTURE);
-            tip = new double[]{x, y, z};
+            tip[0] = x;
+            tip[1] = y;
+            tip[2] = z;
         }
         return tip;
     }

core/src/main/java/art/arcane/iris/engine/object/fungi/FungusGenerator.java

@@ -63,11 +63,7 @@ public final class FungusGenerator {
 
     private static void buildUpright(Map<Vector3i, FungusCellRole> roles, IrisFungus fungus, int height, RNG rng, long baseSeed) {
         int stemHeight = Math.max(1, height);
-        Map<Vector3i, PlatformBlockState> stemCells = new HashMap<>();
-        double[] top = FungusStemBuilder.build(stemCells, fungus, stemHeight, baseSeed);
-        for (Vector3i v : stemCells.keySet()) {
-            roles.put(v, FungusCellRole.STEM);
-        }
+        double[] top = FungusStemBuilder.build(roles, fungus, stemHeight, baseSeed);
 
         int radius = pickRadius(fungus, rng);
         double cx = top[0];

core/src/main/java/art/arcane/iris/engine/object/fungi/FungusStemBuilder.java

@@ -20,7 +20,6 @@ package art.arcane.iris.engine.object.fungi;
 
 import art.arcane.iris.engine.object.IrisFungus;
 import art.arcane.iris.engine.object.tree.TreeFunctions;
-import art.arcane.iris.spi.PlatformBlockState;
 import art.arcane.iris.util.common.math.Vector3i;
 
 import java.util.Map;
@@ -29,7 +28,7 @@ public final class FungusStemBuilder {
     private FungusStemBuilder() {
     }
 
-    public static double[] build(Map<Vector3i, PlatformBlockState> stemCells, IrisFungus fungus, int stemHeight, long seed) {
+    public static double[] build(Map<Vector3i, FungusCellRole> roles, IrisFungus fungus, int stemHeight, long seed) {
         int width = Math.max(1, Math.min(3, fungus.getStemWidth()));
         double maxLean = stemHeight * Math.tan(Math.toRadians(Math.max(0.0, fungus.getStemCurve())));
         double leanRad = Math.toRadians(fungus.getStemLeanAzimuth());
@@ -40,6 +39,7 @@ public final class FungusStemBuilder {
         double waveAzimuth = Math.toRadians(fungus.getStemLeanAzimuth() + 90.0);
         double waveX = Math.sin(waveAzimuth);
         double waveZ = Math.cos(waveAzimuth);
+        double wavePhase = TreeFunctions.valueNoise1D(seed, seed) * Math.PI * 2.0;
 
         double topCx = 0.0;
         double topCz = 0.0;
@@ -48,12 +48,16 @@ public final class FungusStemBuilder {
         for (int y = 0; y < stemHeight; y++) {
             double t = stemHeight <= 1 ? 0.0 : y / (double) (stemHeight - 1);
             double lean = maxLean * (t * t);
-            double wave = waveAmp * Math.sin(2.0 * Math.PI * wavePeriods * t + TreeFunctions.valueNoise1D(seed, seed) * Math.PI * 2.0);
+            double wave = waveAmp * Math.sin(2.0 * Math.PI * wavePeriods * t + wavePhase);
             double cx = lean * leanX + wave * waveX;
             double cz = lean * leanZ + wave * waveZ;
 
-            for (int[] xz : squarePositions(cx, cz, width)) {
-                stemCells.put(new Vector3i(xz[0], y, xz[1]), null);
+            int ox = (width % 2 == 1 ? (int) Math.round(cx) : (int) Math.floor(cx) + 1) - width / 2;
+            int oz = (width % 2 == 1 ? (int) Math.round(cz) : (int) Math.floor(cz) + 1) - width / 2;
+            for (int dx = 0; dx < width; dx++) {
+                for (int dz = 0; dz < width; dz++) {
+                    roles.put(new Vector3i(ox + dx, y, oz + dz), FungusCellRole.STEM);
+                }
             }
 
             topCx = cx;
@@ -62,34 +66,4 @@ public final class FungusStemBuilder {
 
         return new double[]{topCx, topY, topCz};
     }
-
-    static int[][] squarePositions(double cx, double cz, int width) {
-        if (width % 2 == 1) {
-            int half = width / 2;
-            int icx = (int) Math.round(cx);
-            int icz = (int) Math.round(cz);
-            int[][] out = new int[width * width][2];
-            int idx = 0;
-            for (int dx = -half; dx <= half; dx++) {
-                for (int dz = -half; dz <= half; dz++) {
-                    out[idx][0] = icx + dx;
-                    out[idx][1] = icz + dz;
-                    idx++;
-                }
-            }
-            return out;
-        }
-        int ox = (int) Math.floor(cx) - width / 2 + 1;
-        int oz = (int) Math.floor(cz) - width / 2 + 1;
-        int[][] out = new int[width * width][2];
-        int idx = 0;
-        for (int dx = 0; dx < width; dx++) {
-            for (int dz = 0; dz < width; dz++) {
-                out[idx][0] = ox + dx;
-                out[idx][1] = oz + dz;
-                idx++;
-            }
-        }
-        return out;
-    }
 }

core/src/main/java/art/arcane/iris/engine/object/tree/ProceduralTreeGenerator.java

@@ -66,9 +66,10 @@ public final class ProceduralTreeGenerator {
         Map<TreeBlockCanvas.Vec, PlatformBlockState> resolved = new HashMap<>();
         Set<TreeBlockCanvas.Vec> trunkPositions = new HashSet<>();
         Set<TreeBlockCanvas.Vec> leafPositions = new HashSet<>();
+        RNG paletteRng = new RNG(tree.getSeed());
         for (Map.Entry<TreeBlockCanvas.Vec, TreeBlockCanvas.Cell> entry : canvas.getCells().entrySet()) {
             TreeBlockCanvas.Cell cell = entry.getValue();
-            PlatformBlockState state = TreeBlockResolver.resolve(tree, data, cell, entry.getKey());
+            PlatformBlockState state = TreeBlockResolver.resolve(tree, data, cell, entry.getKey(), paletteRng);
             if (state == null) {
                 continue;
             }

core/src/main/java/art/arcane/iris/engine/object/tree/TreeBlockResolver.java

@@ -31,10 +31,7 @@ public final class TreeBlockResolver {
     private TreeBlockResolver() {
     }
 
-    public static PlatformBlockState resolve(IrisProceduralTree tree, IrisData data, TreeBlockCanvas.Cell cell, TreeBlockCanvas.Vec pos) {
-        RNG paletteRng = new RNG(tree.getSeed());
-        RNG posRng = new RNG(tree.getSeed() ^ positionHash(pos));
-
+    public static PlatformBlockState resolve(IrisProceduralTree tree, IrisData data, TreeBlockCanvas.Cell cell, TreeBlockCanvas.Vec pos, RNG paletteRng) {
         switch (cell.role()) {
             case TRUNK -> {
                 PlatformBlockState state = resolveBlock(tree.getTrunk(), tree.getTrunkPalette(), data, pos, paletteRng);
@@ -51,7 +48,7 @@ public final class TreeBlockResolver {
                 return resolveBlock(tree.getLeaves(), tree.getLeavesPalette(), data, pos, paletteRng);
             }
             case SECONDARY_LEAF -> {
-                PlatformBlockState state = resolveSecondaryLeaf(tree, data, pos, paletteRng, posRng);
+                PlatformBlockState state = resolveSecondaryLeaf(tree, data, pos, paletteRng);
                 if (state == null) {
                     state = resolveBlock(tree.getLeaves(), tree.getLeavesPalette(), data, pos, paletteRng);
                 }
@@ -94,12 +91,12 @@ public final class TreeBlockResolver {
         return state;
     }
 
-    private static PlatformBlockState resolveSecondaryLeaf(IrisProceduralTree tree, IrisData data, TreeBlockCanvas.Vec pos, RNG paletteRng, RNG posRng) {
+    private static PlatformBlockState resolveSecondaryLeaf(IrisProceduralTree tree, IrisData data, TreeBlockCanvas.Vec pos, RNG paletteRng) {
         if (TreeTrunkBuilder.paletteSet(tree.getSecondaryLeavesPalette())) {
             return tree.getSecondaryLeavesPalette().get(paletteRng, pos.x(), pos.y(), pos.z(), data);
         }
         if (tree.getWeightedSecondaryLeaves() != null && !tree.getWeightedSecondaryLeaves().isEmpty()) {
-            String picked = pickWeighted(tree, posRng);
+            String picked = pickWeighted(tree, new RNG(tree.getSeed() ^ positionHash(pos)));
             return picked == null ? null : B.getStateOrNull(picked, false);
         }
         if (tree.getSecondaryLeaves() != null && !tree.getSecondaryLeaves().isEmpty()) {

core/src/main/java/art/arcane/iris/engine/object/tree/TreePlausibility.java

@@ -50,7 +50,9 @@ public final class TreePlausibility {
             return;
         }
 
-        Map<TreeBlockCanvas.Vec, Integer> distance = computeDistances(trunkPositions, realLeaves);
+        Map<TreeBlockCanvas.Vec, Integer> distance = tree.isPlausible()
+                ? computeDistances(trunkPositions, realLeaves)
+                : Map.of();
 
         for (TreeBlockCanvas.Vec v : realLeaves) {
             PlatformBlockState leaf = resolved.get(v);

core/src/main/java/art/arcane/iris/engine/object/tree/TreeSupport.java

@@ -18,7 +18,6 @@
 
 package art.arcane.iris.engine.object.tree;
 
-import java.util.ArrayList;
 import java.util.Map;
 
 public final class TreeSupport {
@@ -36,7 +35,7 @@ public final class TreeSupport {
             TreeBlockCanvas.Vec worstWood = null;
             int worstGap = -1;
 
-            for (TreeBlockCanvas.Vec leaf : new ArrayList<>(canvas.getLeaf())) {
+            for (TreeBlockCanvas.Vec leaf : canvas.getLeaf()) {
                 Integer d = dist.get(leaf);
                 if (d != null && d <= LEGAL_DISTANCE) {
                     continue;

core/src/main/java/art/arcane/iris/engine/object/tree/TreeTrunkBuilder.java

@@ -121,7 +121,7 @@ public final class TreeTrunkBuilder {
     }
 
     private static void markExposedEnds(TreeBlockCanvas canvas) {
-        for (TreeBlockCanvas.Vec v : new ArrayList<>(canvas.getTrunk())) {
+        for (TreeBlockCanvas.Vec v : canvas.getTrunk()) {
             if (!canvas.has(v.x(), v.y() + 1, v.z()) || !canvas.has(v.x(), v.y() - 1, v.z())) {
                 canvas.markExposed(v.x(), v.y(), v.z());
             }