Add regional atmosphere: vegetation scrub, ecosystem-driven rain, per-player weather

- New AtmosphereModule (9th in pipeline) derives per-region rain/thunder from
  ecosystem health and pollution score, smoothly interpolating each sim cycle.
- Tree canopy scrubs air pollution: treePressure × 0.003 removed per cycle,
  creating a direct incentive to maintain forests.
- Rain level (0–1) targets ecosystem health / 100 × 0.85; global MC rain adds
  a 0.15 bias so natural weather still matters.
- Thunder level targets pollutionScore / 100 × 0.8; acid rain fires when
  thunder > 0.4 AND pollution > 20, draining soil fertility and water.
- Regional drought: rain < 0.2 raises drought risk proportionally.
- Per-player ClientboundGameEventPacket (RAIN_LEVEL_CHANGE, THUNDER_LEVEL_CHANGE,
  START_RAINING, STOP_RAINING) sent each player-check cycle so each region has
  an independent sky without client-side mixins.
- HUD extended with Rain% and Storm% fields when atmosphere data is present.
- Removed global applyWeatherFeedback() from bootstrap; AtmosphereModule owns
  all rain/drought/acid-rain simulation.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/main/java/com/livingworld/LivingWorldMod.java

@@ -33,9 +33,11 @@ import net.minecraft.world.level.block.state.properties.BlockStateProperties;
 import net.minecraft.world.level.chunk.LevelChunk;
 import net.minecraft.world.level.levelgen.Heightmap;
 import net.minecraft.world.level.storage.LevelResource;
+import net.minecraft.network.protocol.game.ClientboundGameEventPacket;
 import net.neoforged.neoforge.event.tick.ServerTickEvent;
 
 import com.livingworld.bootstrap.LivingWorldBootstrap;
+import com.livingworld.modules.atmosphere.AtmosphereRegionData;
 import com.livingworld.core.LivingWorldConstants;
 import com.livingworld.debug.DiagnosticCategory;
 import com.livingworld.debug.LivingWorldLogger;
@@ -85,6 +87,7 @@ public class LivingWorldMod {
     private int furnaceScanTick = 0;
     private int playerCheckTick = 0;
     private final Map<UUID, RegionCoordinate> playerRegionCache = new HashMap<>();
+    private final Map<UUID, Boolean> playerRainState = new HashMap<>();
     private final Set<RegionCoordinate> biomeInitialized = new HashSet<>();
 
     public LivingWorldMod(IEventBus eventBus) {
@@ -115,6 +118,7 @@ public class LivingWorldMod {
             bootstrap.onServerStopping();
             bootstrap.setOverworldRaining(null);
             playerRegionCache.clear();
+            playerRainState.clear();
             biomeInitialized.clear();
             this.minecraftServer = null;
         });
@@ -235,13 +239,33 @@ public class LivingWorldMod {
                 }
             }
 
-            // Step 2: Compass HUD — display region health while holding a compass, or debug HUD is on.
+            // Regional weather — send per-player rain/thunder packets so each region
+            // has its own sky independently of global Minecraft weather.
+            AtmosphereRegionData atm = bootstrap.getRegionalWeather(coord).orElse(null);
+            if (atm != null) {
+                float rainLevel    = (float) atm.getRainLevel();
+                float thunderLevel = (float) atm.getThunderLevel();
+                boolean wasRaining = playerRainState.getOrDefault(player.getUUID(), false);
+                boolean nowRaining = rainLevel > 0.1f;
+                if (nowRaining != wasRaining) {
+                    player.connection.send(nowRaining
+                            ? new ClientboundGameEventPacket(ClientboundGameEventPacket.START_RAINING, 0f)
+                            : new ClientboundGameEventPacket(ClientboundGameEventPacket.STOP_RAINING, 0f));
+                    playerRainState.put(player.getUUID(), nowRaining);
+                }
+                player.connection.send(new ClientboundGameEventPacket(
+                        ClientboundGameEventPacket.RAIN_LEVEL_CHANGE, rainLevel));
+                player.connection.send(new ClientboundGameEventPacket(
+                        ClientboundGameEventPacket.THUNDER_LEVEL_CHANGE, thunderLevel));
+            }
+
+            // Compass HUD — display region health while holding a compass, or debug HUD is on.
             boolean showHud = player.getMainHandItem().is(Items.COMPASS)
                     || player.getOffhandItem().is(Items.COMPASS)
                     || bootstrap.isHudEnabled(player.getUUID());
             if (showHud) {
                 Optional<RegionMetrics> metricsOpt = bootstrap.getMetricsAt(dimId, player.getX(), player.getZ());
-                metricsOpt.ifPresent(m -> player.displayClientMessage(buildHud(coord, m), true));
+                metricsOpt.ifPresent(m -> player.displayClientMessage(buildHud(coord, m, atm), true));
             }
         }
     }
@@ -272,8 +296,8 @@ public class LivingWorldMod {
         }
     }
 
-    /** Step 2: Builds the action-bar HUD component for a player holding a compass. */
+    /** Builds the action-bar HUD component for a player holding a compass or with /lw hud on. */
-    private Component buildHud(RegionCoordinate coord, RegionMetrics m) {
+    private Component buildHud(RegionCoordinate coord, RegionMetrics m, AtmosphereRegionData atm) {
         double eco  = m.getEcosystemHealth();
         double poll = m.getPollutionScore();
         double soil = m.getSoilQuality();
@@ -284,7 +308,7 @@ public class LivingWorldMod {
         ChatFormatting soilCol = soil > 50 ? ChatFormatting.GREEN  : soil > 25 ? ChatFormatting.YELLOW : ChatFormatting.RED;
         ChatFormatting watCol  = wat  > 50 ? ChatFormatting.GREEN  : wat  > 25 ? ChatFormatting.YELLOW : ChatFormatting.RED;
 
-        return Component.empty()
+        var line = Component.empty()
                 .append(Component.literal("[LW] ").withStyle(ChatFormatting.GOLD))
                 .append(Component.literal(String.format("(%d,%d) ", coord.x(), coord.z())).withStyle(ChatFormatting.GRAY))
                 .append(Component.literal("Eco:").withStyle(ChatFormatting.WHITE))
@@ -295,5 +319,19 @@ public class LivingWorldMod {
                 .append(Component.literal(String.format("%.0f ", soil)).withStyle(soilCol))
                 .append(Component.literal("Wat:").withStyle(ChatFormatting.WHITE))
                 .append(Component.literal(String.format("%.0f", wat)).withStyle(watCol));
+
+        if (atm != null) {
+            double rain    = atm.getRainLevel()    * 100;
+            double thunder = atm.getThunderLevel() * 100;
+            ChatFormatting rainCol = rain > 50 ? ChatFormatting.AQUA : rain > 20 ? ChatFormatting.YELLOW : ChatFormatting.RED;
+            line.append(Component.literal(" Rain:").withStyle(ChatFormatting.WHITE))
+                .append(Component.literal(String.format("%.0f%%", rain)).withStyle(rainCol));
+            if (thunder > 15) {
+                ChatFormatting stormCol = thunder > 50 ? ChatFormatting.RED : ChatFormatting.YELLOW;
+                line.append(Component.literal(" Storm:").withStyle(ChatFormatting.WHITE))
+                    .append(Component.literal(String.format("%.0f%%", thunder)).withStyle(stormCol));
+            }
+        }
+        return line;
     }
 }

src/main/java/com/livingworld/bootstrap/LivingWorldBootstrap.java

@@ -33,6 +33,8 @@ import com.livingworld.modules.vegetation.VegetationModule;
 import com.livingworld.modules.vegetation.VegetationRegionData;
 import com.livingworld.modules.water.WaterModule;
 import com.livingworld.modules.water.WaterRegionData;
+import com.livingworld.modules.atmosphere.AtmosphereModule;
+import com.livingworld.modules.atmosphere.AtmosphereRegionData;
 import com.livingworld.modules.worldeffects.WorldEffectsModule;
 import com.livingworld.platform.BlockBreakInfo;
 import com.livingworld.platform.PlatformAdapter;
@@ -63,11 +65,6 @@ import net.minecraft.commands.CommandSourceStack;
  */
 public final class LivingWorldBootstrap {
 
-    private static final double RAIN_MOISTURE_GAIN    = 0.3;
-    private static final double RAIN_DROUGHT_RELIEF   = 0.15;
-    private static final double DRY_DROUGHT_INCREASE  = 0.05;
-    private static final double ACID_RAIN_THRESHOLD   = 20.0;
-    private static final double ACID_FERTILITY_DRAIN  = 0.0005;
     private static final double WIND_BOOST   = 0.5;
     private static final double WIND_DRIFT_MAX = 0.05; // radians per sim cycle
 
@@ -82,6 +79,7 @@ public final class LivingWorldBootstrap {
     private ModuleRegistry moduleRegistry;
     private SimulationManager simulationManager;
     private WorldEffectsModule worldEffectsModule;
+    private AtmosphereModule atmosphereModule;
     private BooleanSupplier overworldRaining = () -> false;
     private boolean initialized;
     private boolean serverReady;
@@ -327,7 +325,6 @@ public final class LivingWorldBootstrap {
         long previousSimulationTick = simulationManager.getSimulationTickCounter();
         simulationManager.onMinecraftServerTick();
         if (simulationManager.getSimulationTickCounter() != previousSimulationTick) {
-            applyWeatherFeedback();
             spreadPollutionAcrossRegions();
             regionManager.saveDirtyRegions();
         }
@@ -379,43 +376,11 @@ public final class LivingWorldBootstrap {
         }
     }
 
-    private void applyWeatherFeedback() {
+    /** Returns the current atmospheric state for a region, if it has been initialised. */
-        boolean raining = overworldRaining.getAsBoolean();
+    public Optional<AtmosphereRegionData> getRegionalWeather(RegionCoordinate coord) {
-        for (Region region : regionManager.getActiveRegions()) {
+        if (!serverReady || coord == null) return Optional.empty();
-            if (!"minecraft:overworld".equals(region.getCoordinate().dimensionId())) {
+        return regionManager.resolve(coord)
-                continue;
+                .flatMap(r -> r.getModuleData().get(AtmosphereModule.MODULE_ID, AtmosphereRegionData.class));
-            }
-            WaterRegionData water = region.getModuleData()
-                    .get(WaterModule.MODULE_ID, WaterRegionData.class)
-                    .orElse(null);
-            if (water == null) {
-                continue;
-            }
-            if (raining) {
-                water.setWaterAvailability(water.getWaterAvailability() + RAIN_MOISTURE_GAIN);
-                water.setDroughtRisk(water.getDroughtRisk() - RAIN_DROUGHT_RELIEF);
-
-                // Acid rain: polluted rainfall degrades soil and water quality.
-                double pollutionScore = region.getMetrics().getPollutionScore();
-                if (pollutionScore > ACID_RAIN_THRESHOLD) {
-                    double acidStrength = (pollutionScore - ACID_RAIN_THRESHOLD) * ACID_FERTILITY_DRAIN;
-                    SoilRegionData soil = region.getModuleData()
-                            .get(SoilModule.MODULE_ID, SoilRegionData.class)
-                            .orElse(null);
-                    if (soil != null) {
-                        soil.setFertility(Math.max(0, soil.getFertility() - acidStrength));
-                        soil.setContamination(Math.min(100, soil.getContamination() + acidStrength * 0.5));
-                        region.getModuleData().put(SoilModule.MODULE_ID, soil);
-                    }
-                    water.setWaterAvailability(
-                            Math.max(0, water.getWaterAvailability() - acidStrength * 0.3));
-                }
-            } else {
-                water.setDroughtRisk(water.getDroughtRisk() + DRY_DROUGHT_INCREASE);
-            }
-            region.getModuleData().put(WaterModule.MODULE_ID, water);
-            regionManager.markDirty(region);
-        }
     }
 
     /** Toggles the debug HUD for the given player. Returns true if HUD is now enabled. */
@@ -665,6 +630,18 @@ public final class LivingWorldBootstrap {
                         r.readDouble("stress",          20.0),
                         r.readDouble("resilience",      50.0),
                         r.readDouble("recoveryRate",     5.0))));
+
+        service.registerModuleCodec(
+                AtmosphereModule.MODULE_ID,
+                (data, w) -> {
+                    AtmosphereRegionData d = data.get(AtmosphereModule.MODULE_ID, AtmosphereRegionData.class)
+                            .orElseGet(AtmosphereRegionData::defaults);
+                    w.writeDouble("rainLevel",    d.getRainLevel());
+                    w.writeDouble("thunderLevel", d.getThunderLevel());
+                },
+                (r, data) -> data.put(AtmosphereModule.MODULE_ID, new AtmosphereRegionData(
+                        r.readDouble("rainLevel",    0.4),
+                        r.readDouble("thunderLevel", 0.0))));
     }
 
     /**
@@ -684,10 +661,12 @@ public final class LivingWorldBootstrap {
         registry.register(new EcosystemModule());
         worldEffectsModule = new WorldEffectsModule();
         registry.register(worldEffectsModule);
+        atmosphereModule = new AtmosphereModule(() -> overworldRaining.getAsBoolean());
+        registry.register(atmosphereModule);
         LivingWorldLogger.info(
                 DiagnosticCategory.BOOTSTRAP,
-                "Registered 8 ecosystem modules (pollution → soil → water → vegetation"
+                "Registered 9 ecosystem modules (pollution → soil → water → vegetation"
-                        + " → resources → recovery → ecosystem → worldeffects).");
+                        + " → resources → recovery → ecosystem → worldeffects → atmosphere).");
     }
 
     private void requireInitialized() {

src/main/java/com/livingworld/modules/atmosphere/AtmosphereModule.java

@@ -0,0 +1,184 @@
+package com.livingworld.modules.atmosphere;
+
+import com.livingworld.data.serialization.PersistenceReader;
+import com.livingworld.data.serialization.PersistenceWriter;
+import com.livingworld.events.LivingWorldEvent;
+import com.livingworld.modules.ModuleContext;
+import com.livingworld.modules.ModuleMetadata;
+import com.livingworld.modules.ModuleUpdateResult;
+import com.livingworld.modules.RegionUpdateContext;
+import com.livingworld.modules.ServerContext;
+import com.livingworld.modules.SimulationModule;
+import com.livingworld.modules.pollution.PollutionModule;
+import com.livingworld.modules.pollution.PollutionRegionData;
+import com.livingworld.modules.soil.SoilModule;
+import com.livingworld.modules.soil.SoilRegionData;
+import com.livingworld.modules.vegetation.VegetationModule;
+import com.livingworld.modules.vegetation.VegetationRegionData;
+import com.livingworld.modules.water.WaterModule;
+import com.livingworld.modules.water.WaterRegionData;
+import com.livingworld.regions.Region;
+
+import java.util.List;
+import java.util.function.BooleanSupplier;
+
+/**
+ * Drives per-region weather from ecosystem state and applies atmospheric feedback
+ * to other simulation layers.
+ *
+ * <h3>Pipeline position</h3>
+ * Runs last (after WorldEffects) so ecosystem health and pollution scores are final
+ * before weather targets are computed.
+ *
+ * <h3>Per-cycle rules</h3>
+ * <ol>
+ *   <li>Tree canopy scrubs air pollution: {@code airPollution -= treePressure × TREE_SCRUB_RATE}.
+ *   <li>Target rain level is derived from ecosystem health (healthy = wet, degraded = drought).
+ *       Global Minecraft rain adds a small bias so natural weather still matters.
+ *   <li>Target thunder level is derived from pollution (polluted = stormy).
+ *   <li>Rain and thunder smoothly interpolate toward their targets each cycle.
+ *   <li>Rain fills water availability; drought raises drought risk.
+ *   <li>High thunder + high pollution triggers acid rain (drains soil fertility).
+ * </ol>
+ */
+public final class AtmosphereModule implements SimulationModule {
+
+    public static final String MODULE_ID = "atmosphere";
+
+    // Tree scrub: treePressure (0-100) × rate removed from air pollution per cycle.
+    private static final double TREE_SCRUB_RATE       = 0.003;
+
+    // Rain target ceiling when ecosystem is pristine (no global rain).
+    private static final double MAX_RAIN_FROM_ECO     = 0.85;
+    // Additive bias when Minecraft's overworld is actually raining.
+    private static final double GLOBAL_RAIN_BIAS      = 0.15;
+
+    // Smoothing rates — weather changes slowly, not instantly.
+    private static final double RAIN_SMOOTHING        = 0.05;
+    private static final double THUNDER_SMOOTHING     = 0.03;
+
+    // Rain < this → drought conditions worsen each cycle.
+    private static final double DROUGHT_THRESHOLD     = 0.2;
+    private static final double RAIN_MOISTURE_GAIN    = 0.3;
+    private static final double RAIN_DROUGHT_RELIEF   = 0.15;
+    private static final double DRY_DROUGHT_INCREASE  = 0.05;
+
+    // Acid rain fires when BOTH thunder and pollution exceed these thresholds.
+    private static final double ACID_THUNDER_THRESHOLD = 0.4;
+    private static final double ACID_POLL_THRESHOLD    = 20.0;
+    private static final double ACID_FERTILITY_DRAIN   = 0.0005;
+
+    private static final ModuleMetadata METADATA = new ModuleMetadata(
+            MODULE_ID,
+            "Atmosphere",
+            "1.0.0",
+            "Per-region weather driven by ecosystem health and pollution. Trees scrub air pollution.",
+            "9",
+            List.of(),
+            List.of(),
+            true,
+            true,
+            false);
+
+    private final BooleanSupplier globalRaining;
+
+    public AtmosphereModule(BooleanSupplier globalRaining) {
+        this.globalRaining = globalRaining;
+    }
+
+    @Override public String getModuleId()               { return MODULE_ID; }
+    @Override public ModuleMetadata getMetadata()       { return METADATA; }
+    @Override public void initialize(ModuleContext ctx) {}
+    @Override public void onServerStarted(ServerContext ctx) {}
+    @Override public void onLivingWorldEvent(LivingWorldEvent event) {}
+    @Override public void saveModuleData(PersistenceWriter w) {}
+    @Override public void loadModuleData(PersistenceReader r) {}
+    @Override public void shutdown() {}
+
+    @Override
+    public void createDefaultRegionData(Region region) {
+        if (!region.getModuleData().contains(MODULE_ID)) {
+            region.getModuleData().put(MODULE_ID, AtmosphereRegionData.defaults());
+        }
+    }
+
+    @Override
+    public ModuleUpdateResult updateRegion(RegionUpdateContext context) {
+        Region region = context.getRegion();
+
+        AtmosphereRegionData data = region.getModuleData()
+                .get(MODULE_ID, AtmosphereRegionData.class)
+                .orElseGet(AtmosphereRegionData::defaults);
+
+        // 1. Vegetation scrubs air pollution.
+        VegetationRegionData veg = region.getModuleData()
+                .get(VegetationModule.MODULE_ID, VegetationRegionData.class)
+                .orElse(null);
+        PollutionRegionData pollution = region.getModuleData()
+                .get(PollutionModule.MODULE_ID, PollutionRegionData.class)
+                .orElse(null);
+
+        if (veg != null && pollution != null) {
+            double scrub = veg.getTreePressure() * TREE_SCRUB_RATE;
+            pollution.addPollution(-scrub, 0.0, 0.0);
+            region.getModuleData().put(PollutionModule.MODULE_ID, pollution);
+            // Recompute pollution score now that trees have scrubbed the air.
+            double pollScore = pollution.getAirPollution()    * 0.40
+                             + pollution.getGroundPollution() * 0.35
+                             + pollution.getWaterPollution()  * 0.25;
+            region.getMetrics().setPollutionScore(pollScore);
+        }
+
+        // 2. Compute targets.
+        double ecosystemHealth = region.getMetrics().getEcosystemHealth();
+        double pollScore       = region.getMetrics().getPollutionScore();
+        boolean mcRaining      = globalRaining.getAsBoolean();
+
+        double targetRain    = clamp01(ecosystemHealth / 100.0 * MAX_RAIN_FROM_ECO
+                                       + (mcRaining ? GLOBAL_RAIN_BIAS : 0.0));
+        double targetThunder = clamp01(pollScore / 100.0 * 0.8);
+
+        // 3. Smooth toward targets.
+        double rain    = data.getRainLevel()    + (targetRain    - data.getRainLevel())    * RAIN_SMOOTHING;
+        double thunder = data.getThunderLevel() + (targetThunder - data.getThunderLevel()) * THUNDER_SMOOTHING;
+        data.setRainLevel(rain);
+        data.setThunderLevel(thunder);
+
+        // 4. Apply rain effects to water availability and drought risk.
+        WaterRegionData water = region.getModuleData()
+                .get(WaterModule.MODULE_ID, WaterRegionData.class)
+                .orElse(null);
+        if (water != null) {
+            water.setWaterAvailability(
+                    Math.min(100, water.getWaterAvailability() + rain * RAIN_MOISTURE_GAIN));
+            if (rain < DROUGHT_THRESHOLD) {
+                water.setDroughtRisk(
+                        Math.min(100, water.getDroughtRisk() + DRY_DROUGHT_INCREASE * (1.0 - rain)));
+            } else {
+                water.setDroughtRisk(
+                        Math.max(0, water.getDroughtRisk() - RAIN_DROUGHT_RELIEF * rain));
+            }
+
+            // 5. Acid rain: stormy + polluted atmosphere corrodes soil and water.
+            if (thunder > ACID_THUNDER_THRESHOLD && pollScore > ACID_POLL_THRESHOLD) {
+                double acidStrength = thunder * (pollScore - ACID_POLL_THRESHOLD) * ACID_FERTILITY_DRAIN;
+                SoilRegionData soil = region.getModuleData()
+                        .get(SoilModule.MODULE_ID, SoilRegionData.class)
+                        .orElse(null);
+                if (soil != null) {
+                    soil.setFertility(Math.max(0, soil.getFertility() - acidStrength));
+                    soil.setContamination(Math.min(100, soil.getContamination() + acidStrength * 0.5));
+                    region.getModuleData().put(SoilModule.MODULE_ID, soil);
+                }
+                water.setWaterAvailability(
+                        Math.max(0, water.getWaterAvailability() - acidStrength * 0.3));
+            }
+            region.getModuleData().put(WaterModule.MODULE_ID, water);
+        }
+
+        region.getModuleData().put(MODULE_ID, data);
+        return ModuleUpdateResult.changed();
+    }
+
+    private static double clamp01(double v) { return Math.min(1.0, Math.max(0.0, v)); }
+}

src/main/java/com/livingworld/modules/atmosphere/AtmosphereRegionData.java

@@ -0,0 +1,44 @@
+package com.livingworld.modules.atmosphere;
+
+/**
+ * Per-region atmospheric state tracked by {@link AtmosphereModule}.
+ *
+ * <p>Both values smoothly interpolate toward ecosystem-derived targets each
+ * simulation cycle and are used to drive per-player weather packets.
+ *
+ * <ul>
+ *   <li><b>rainLevel</b>   – 0.0 = drought, 1.0 = heavy rainfall
+ *   <li><b>thunderLevel</b> – 0.0 = calm, 1.0 = heavy storm (acid rain above 0.4)
+ * </ul>
+ */
+public final class AtmosphereRegionData {
+
+    private double rainLevel;
+    private double thunderLevel;
+
+    public AtmosphereRegionData(double rainLevel, double thunderLevel) {
+        this.rainLevel    = clamp(rainLevel);
+        this.thunderLevel = clamp(thunderLevel);
+    }
+
+    public static AtmosphereRegionData defaults() {
+        return new AtmosphereRegionData(0.4, 0.0);
+    }
+
+    public double getRainLevel()    { return rainLevel; }
+    public double getThunderLevel() { return thunderLevel; }
+
+    public void setRainLevel(double v)    { this.rainLevel    = clamp(v); }
+    public void setThunderLevel(double v) { this.thunderLevel = clamp(v); }
+
+    public AtmosphereRegionData copy() {
+        return new AtmosphereRegionData(rainLevel, thunderLevel);
+    }
+
+    private static double clamp(double v) { return Math.min(1.0, Math.max(0.0, v)); }
+
+    @Override
+    public String toString() {
+        return "AtmosphereRegionData{rain=" + rainLevel + ", thunder=" + thunderLevel + "}";
+    }
+}