Persist random Age traits

src/main/java/net/dnorberg/rivencraft/book/AgeDefinition.java

@@ -15,18 +15,20 @@ public record AgeDefinition(
         int generationVersion,
         long createdGameTime,
         ResourceLocation dimensionId,
-        BlockPos spawn
+        BlockPos spawn,
+        AgeTraits traits
 ) {
     public static final ResourceLocation RANDOM_VANILLA_PROFILE = ResourceLocation.fromNamespaceAndPath(
             Rivencraft.MOD_ID, "random_vanilla"
     );
-    public static final int CURRENT_GENERATION_VERSION = 2;
+    public static final int CURRENT_GENERATION_VERSION = 3;
 
     public AgeDefinition {
         Objects.requireNonNull(id, "id");
         Objects.requireNonNull(name, "name");
         Objects.requireNonNull(generationProfile, "generationProfile");
         Objects.requireNonNull(dimensionId, "dimensionId");
+        Objects.requireNonNull(traits, "traits");
     }
 
     public static ResourceLocation dimensionId(UUID ageId) {
@@ -57,6 +59,6 @@ public record AgeDefinition(
 
     public AgeDefinition withSpawn(BlockPos spawn) {
         return new AgeDefinition(id, name, seed, generationProfile, generationVersion,
-                createdGameTime, dimensionId, spawn.immutable());
+                createdGameTime, dimensionId, spawn.immutable(), traits);
     }
 }

src/main/java/net/dnorberg/rivencraft/book/AgeRegistrySavedData.java

@@ -28,6 +28,13 @@ public final class AgeRegistrySavedData extends SavedData {
     private static final String SPAWN_X_TAG = "SpawnX";
     private static final String SPAWN_Y_TAG = "SpawnY";
     private static final String SPAWN_Z_TAG = "SpawnZ";
+    private static final String TRAITS_TAG = "Traits";
+    private static final String BIOME_DISTRIBUTION_TAG = "BiomeDistribution";
+    private static final String LIGHTING_TAG = "Lighting";
+    private static final String WEATHER_TAG = "Weather";
+    private static final String CELESTIAL_PERIOD_TAG = "CelestialPeriod";
+    private static final String CELESTIAL_ANGLE_TAG = "CelestialAngle";
+    private static final String CELESTIAL_PHASE_TAG = "CelestialPhase";
     private static final Factory<AgeRegistrySavedData> FACTORY = new Factory<>(
             AgeRegistrySavedData::new,
             AgeRegistrySavedData::load,
@@ -88,7 +95,8 @@ public final class AgeRegistrySavedData extends SavedData {
                 AgeDefinition.CURRENT_GENERATION_VERSION,
                 createdGameTime,
                 dimensionId,
-                null
+                null,
+                AgeTraits.select(seed)
         );
         ages.put(created.id(), created);
         setDirty();
@@ -123,7 +131,8 @@ public final class AgeRegistrySavedData extends SavedData {
                     entry.contains(VERSION_TAG) ? entry.getInt(VERSION_TAG) : 1,
                     entry.getLong(CREATED_TIME_TAG),
                     dimensionId,
-                    spawn
+                    spawn,
+                    readTraits(entry)
             ));
         }
         return data;
@@ -148,12 +157,40 @@ public final class AgeRegistrySavedData extends SavedData {
                         entry.putInt(SPAWN_Y_TAG, age.spawn().getY());
                         entry.putInt(SPAWN_Z_TAG, age.spawn().getZ());
                     }
+                    CompoundTag traits = new CompoundTag();
+                    traits.putString(BIOME_DISTRIBUTION_TAG, age.traits().biomeDistribution().name());
+                    traits.putString(LIGHTING_TAG, age.traits().lighting().name());
+                    traits.putString(WEATHER_TAG, age.traits().weather().name());
+                    traits.putDouble(CELESTIAL_PERIOD_TAG, age.traits().celestialPeriod());
+                    traits.putFloat(CELESTIAL_ANGLE_TAG, age.traits().celestialAngle());
+                    traits.putFloat(CELESTIAL_PHASE_TAG, age.traits().celestialPhase());
+                    entry.put(TRAITS_TAG, traits);
                     serializedAges.add(entry);
                 });
         tag.put(AGES_TAG, serializedAges);
         return tag;
     }
 
+    private static AgeTraits readTraits(CompoundTag age) {
+        if (!age.contains(TRAITS_TAG, CompoundTag.TAG_COMPOUND)) {
+            return AgeTraits.LEGACY_DEFAULTS;
+        }
+        CompoundTag traits = age.getCompound(TRAITS_TAG);
+        AgeTraits defaults = AgeTraits.LEGACY_DEFAULTS;
+        try {
+            return new AgeTraits(
+                    AgeTraits.parseOrDefault(traits.getString(BIOME_DISTRIBUTION_TAG), defaults.biomeDistribution()),
+                    AgeTraits.parseOrDefault(traits.getString(LIGHTING_TAG), defaults.lighting()),
+                    AgeTraits.parseOrDefault(traits.getString(WEATHER_TAG), defaults.weather()),
+                    traits.contains(CELESTIAL_PERIOD_TAG) ? traits.getDouble(CELESTIAL_PERIOD_TAG) : defaults.celestialPeriod(),
+                    traits.contains(CELESTIAL_ANGLE_TAG) ? traits.getFloat(CELESTIAL_ANGLE_TAG) : defaults.celestialAngle(),
+                    traits.contains(CELESTIAL_PHASE_TAG) ? traits.getFloat(CELESTIAL_PHASE_TAG) : defaults.celestialPhase()
+            );
+        } catch (IllegalArgumentException exception) {
+            return defaults;
+        }
+    }
+
     private static String normalizedName(String name) {
         String normalized = name.strip();
         return normalized.isEmpty() ? "Unnamed Age" : normalized;

src/main/java/net/dnorberg/rivencraft/book/AgeTraits.java

@@ -0,0 +1,79 @@
+package net.dnorberg.rivencraft.book;
+
+import java.util.Random;
+
+/** Immutable random-Age traits selected once from the Age seed. */
+public record AgeTraits(
+        BiomeDistribution biomeDistribution,
+        Lighting lighting,
+        Weather weather,
+        double celestialPeriod,
+        float celestialAngle,
+        float celestialPhase
+) {
+    public static final double MIN_CELESTIAL_PERIOD = 0.2D;
+    public static final double MAX_CELESTIAL_PERIOD = 2.0D;
+    public static final float MIN_CELESTIAL_ANGLE = 0.0F;
+    public static final float MAX_CELESTIAL_ANGLE = 360.0F;
+    public static final float MIN_CELESTIAL_PHASE = 0.0F;
+    public static final float MAX_CELESTIAL_PHASE = 1.0F;
+
+    public static final AgeTraits LEGACY_DEFAULTS = new AgeTraits(
+            BiomeDistribution.NATIVE, Lighting.NORMAL, Weather.NORMAL,
+            1.0D, 0.0F, 0.0F
+    );
+
+    public AgeTraits {
+        if (biomeDistribution == null || lighting == null || weather == null) {
+            throw new IllegalArgumentException("Age trait choices cannot be null");
+        }
+        if (celestialPeriod < MIN_CELESTIAL_PERIOD || celestialPeriod > MAX_CELESTIAL_PERIOD) {
+            throw new IllegalArgumentException("Celestial period is outside the legacy range");
+        }
+        if (celestialAngle < MIN_CELESTIAL_ANGLE || celestialAngle >= MAX_CELESTIAL_ANGLE) {
+            throw new IllegalArgumentException("Celestial angle is outside the legacy range");
+        }
+        if (celestialPhase < MIN_CELESTIAL_PHASE || celestialPhase >= MAX_CELESTIAL_PHASE) {
+            throw new IllegalArgumentException("Celestial phase is outside the legacy range");
+        }
+    }
+
+    public static AgeTraits select(long seed) {
+        Random random = new Random(seed ^ 0x524956454E435241L);
+        return new AgeTraits(
+                randomChoice(random, BiomeDistribution.values()),
+                randomChoice(random, Lighting.values()),
+                randomChoice(random, Weather.values()),
+                MIN_CELESTIAL_PERIOD
+                        + random.nextDouble() * (MAX_CELESTIAL_PERIOD - MIN_CELESTIAL_PERIOD),
+                random.nextFloat() * MAX_CELESTIAL_ANGLE,
+                random.nextFloat()
+        );
+    }
+
+    public static <E extends Enum<E>> E parseOrDefault(String value, E fallback) {
+        try {
+            @SuppressWarnings("unchecked")
+            Class<E> type = (Class<E>) fallback.getDeclaringClass();
+            return Enum.valueOf(type, value);
+        } catch (IllegalArgumentException exception) {
+            return fallback;
+        }
+    }
+
+    private static <E> E randomChoice(Random random, E[] values) {
+        return values[random.nextInt(values.length)];
+    }
+
+    public enum BiomeDistribution {
+        NATIVE, SINGLE, TILED, GRID, TINY, SMALL, MEDIUM, LARGE, HUGE
+    }
+
+    public enum Lighting {
+        NORMAL, DARK, BRIGHT
+    }
+
+    public enum Weather {
+        NORMAL, FAST, SLOW, OFF, ALWAYS, CLOUDY, RAIN, SNOW, STORM
+    }
+}

src/main/java/net/dnorberg/rivencraft/gametest/LinkingGameTests.java

@@ -9,6 +9,7 @@ import net.dnorberg.rivencraft.book.AgeRegistrySavedData;
 import net.dnorberg.rivencraft.book.LinkTarget;
 import net.dnorberg.rivencraft.book.LinkingService;
 import net.dnorberg.rivencraft.book.AgeVisitSavedData;
+import net.dnorberg.rivencraft.book.AgeTraits;
 import net.dnorberg.rivencraft.item.DescriptiveBookItem;
 import net.dnorberg.rivencraft.item.LinkingBookItem;
 import net.dnorberg.rivencraft.registry.ModDataComponents;
@@ -118,6 +119,11 @@ public final class LinkingGameTests {
                 "A page-free book must select a supported legacy-inspired terrain profile");
         helper.assertValueEqual(first.generationVersion(), AgeDefinition.CURRENT_GENERATION_VERSION,
                 "New Ages must record the current generation algorithm version");
+        helper.assertValueEqual(first.traits(), AgeTraits.select(first.seed()),
+                "A page-free book must persist the deterministic traits selected from its seed");
+        helper.assertTrue(first.traits().celestialPeriod() >= AgeTraits.MIN_CELESTIAL_PERIOD
+                        && first.traits().celestialPeriod() <= AgeTraits.MAX_CELESTIAL_PERIOD,
+                "The celestial period must remain inside Mystcraft Legacy's random range");
         helper.assertTrue(first.seed() != another.seed(), "Distinct Age UUIDs must receive distinct random seeds");
         helper.succeed();
     }
@@ -158,7 +164,8 @@ public final class LinkingGameTests {
                     net.minecraft.resources.ResourceLocation.fromNamespaceAndPath(
                             Rivencraft.MOD_ID, "gametest/" + profile.getPath() + "_" + id
                     ),
-                    null
+                    null,
+                    AgeTraits.select(id.getMostSignificantBits())
             );
             var level = AgeDimensionService.ensureLoaded(helper.getLevel().getServer(), definition);
             helper.assertTrue(level != null, "The " + profile + " profile must load a runtime dimension");