Add authored Age skies and celestial pages (#44)

README.md

@@ -124,6 +124,17 @@ the top or underside of one of its blocks. Insert a bound Linking or Descriptive
 Book to activate it; the book remains visible on the receptacle. A Linking Book aimed at its
 own dimension still opens a visual portal, but travel requires Intra Linking.
 
+Sky writing includes eight color pages and a Static Sky page. Multiple sky-color
+pages blend their colors, tinting the Age sky, book preview, and the fallback
+surface of portals linked there. Multiple celestial-color pages blend for the
+next written sun or moon. An Age may have no suns or moons at all;
+Static Sky animates the sky with television-like noise. Sun and Moon pages add
+independent bodies; preceding color, size, angle, period, phase, and direction
+pages configure the next body. The third and each subsequent sun add increasing
+instability. Newly generated page-free Ages also choose a deterministic sky,
+color, and celestial arrangement from their Age seed; older saved Ages retain
+their previous sky.
+
 Craft a Book Binder from three iron ingots and five planks. Put leather or an
 empty Notebook in the left cover slot. Enter a title, then place a Link Panel
 Page first in the horizontal page strip. Click a page in the strip with a

gradle.properties

@@ -36,7 +36,7 @@ mod_name=Rivencraft
 # The license of the mod. Review your options at https://choosealicense.com/. All Rights Reserved is the default.
 mod_license=LGPL-3.0-or-later
 # The mod version. Rivencraft uses the x.y.z.b policy documented in README.md.
-mod_version=0.6.8.4
+mod_version=0.6.8.7
 immersive_portals_version=6.0.7
 terrablender_version=4.1.0.8
 serene_seasons_version_id=pHEgQQUE

src/main/java/net/dnorberg/rivencraft/block/entity/BookReceptacleBlockEntity.java

@@ -1,6 +1,7 @@
 package net.dnorberg.rivencraft.block.entity;
 
 import net.dnorberg.rivencraft.book.LinkTarget;
+import net.dnorberg.rivencraft.book.AgeEnvironmentCompiler;
 import net.dnorberg.rivencraft.registry.ModBlockEntities;
 import net.dnorberg.rivencraft.portal.CrystalPortalNetwork;
 import net.minecraft.nbt.NbtOps;
@@ -20,8 +21,10 @@ import net.neoforged.fml.ModList;
 public final class BookReceptacleBlockEntity extends BlockEntity {
     private static final String BOOK_TAG = "Book";
     private static final String DESTINATION_TAG = "Destination";
+    private static final String SKY_COLOR_TAG = "SkyColor";
     private ItemStack book = ItemStack.EMPTY;
     private LinkTarget destination;
+    private int skyColor = 0xFFFFFF;
     private boolean restoreView = true;
 
     public BookReceptacleBlockEntity(BlockPos pos, BlockState state) {
@@ -30,6 +33,7 @@ public final class BookReceptacleBlockEntity extends BlockEntity {
 
     public ItemStack getBook() { return book; }
     public LinkTarget destination() { return destination; }
+    public int skyColor() { return skyColor; }
 
     public void setBook(ItemStack stack) {
         book = stack.copyWithCount(1);
@@ -38,6 +42,12 @@ public final class BookReceptacleBlockEntity extends BlockEntity {
 
     public void setDestination(LinkTarget target) {
         destination = target;
+        skyColor = 0xFFFFFF;
+        if (target != null && level instanceof ServerLevel server) {
+            ServerLevel targetLevel = server.getServer().getLevel(target.location().dimension());
+            if (targetLevel != null) skyColor = AgeEnvironmentCompiler.previewSkyColor(
+                    targetLevel, target.location().pos()) & 0xFFFFFF;
+        }
         sync();
     }
 
@@ -45,6 +55,7 @@ public final class BookReceptacleBlockEntity extends BlockEntity {
         ItemStack result = book;
         book = ItemStack.EMPTY;
         destination = null;
+        skyColor = 0xFFFFFF;
         sync();
         return result;
     }
@@ -63,6 +74,7 @@ public final class BookReceptacleBlockEntity extends BlockEntity {
                 : ItemStack.EMPTY;
         destination = tag.contains(DESTINATION_TAG)
                 ? LinkTarget.CODEC.parse(NbtOps.INSTANCE, tag.get(DESTINATION_TAG)).result().orElse(null) : null;
+        skyColor = tag.contains(SKY_COLOR_TAG) ? tag.getInt(SKY_COLOR_TAG) & 0xFFFFFF : 0xFFFFFF;
         restoreView = true;
     }
 
@@ -72,6 +84,7 @@ public final class BookReceptacleBlockEntity extends BlockEntity {
         if (!book.isEmpty()) tag.put(BOOK_TAG, book.save(registries));
         if (destination != null) LinkTarget.CODEC.encodeStart(NbtOps.INSTANCE, destination)
                 .result().ifPresent(encoded -> tag.put(DESTINATION_TAG, encoded));
+        if (destination != null) tag.putInt(SKY_COLOR_TAG, skyColor);
     }
 
     @Override public Packet<ClientGamePacketListener> getUpdatePacket() {

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

@@ -28,7 +28,8 @@ public record AgeDefinition(
     public static final ResourceLocation RANDOM_VANILLA_PROFILE = ResourceLocation.fromNamespaceAndPath(
             Rivencraft.MOD_ID, "random_vanilla"
     );
-    public static final int CURRENT_GENERATION_VERSION = 16;
+    public static final int LEGACY_GENERATOR_CUTOFF = 16;
+    public static final int CURRENT_GENERATION_VERSION = AgeSkyProfile.RANDOM_SKY_GENERATION_VERSION;
 
     public AgeDefinition {
         Objects.requireNonNull(id, "id");

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

@@ -352,7 +352,7 @@ public final class AgeDimensionService {
                     server.registryAccess().lookupOrThrow(Registries.STRUCTURE_SET),
                     server.registryAccess().lookupOrThrow(Registries.PLACED_FEATURE)
             );
-            return age.generationVersion() < AgeDefinition.CURRENT_GENERATION_VERSION
+            return age.generationVersion() < AgeDefinition.LEGACY_GENERATOR_CUTOFF
                     ? new FlatLevelSource(settings) : new AgeFlatChunkGenerator(biomeSource, settings, features, age.seed(), libraryAgeSymbols);
         }
         if (profile.terrain() == AgeRuntimeProfile.Terrain.VOID) {
@@ -362,7 +362,7 @@ public final class AgeDimensionService {
                     List.of()
             );
             settings.updateLayers();
-            return age.generationVersion() < AgeDefinition.CURRENT_GENERATION_VERSION
+            return age.generationVersion() < AgeDefinition.LEGACY_GENERATOR_CUTOFF
                     ? new FlatLevelSource(settings) : new AgeFlatChunkGenerator(biomeSource, settings, features, age.seed(), libraryAgeSymbols);
         }
 
@@ -372,7 +372,7 @@ public final class AgeDimensionService {
         NoiseGeneratorSettings baseSettings = noiseSettings.getOrThrow(settingsKey).value();
         Holder<NoiseGeneratorSettings> settings = Holder.direct(withBiomeMaterialRules(baseSettings));
         boolean caveTerrain = AgeBiomeSelection.isCave(profile);
-        return age.generationVersion() < AgeDefinition.CURRENT_GENERATION_VERSION
+        return age.generationVersion() < AgeDefinition.LEGACY_GENERATOR_CUTOFF
                 ? new NoiseBasedChunkGenerator(biomeSource, settings)
                 : new AgeFeatureChunkGenerator(biomeSource, settings, features, age.seed(),
                         caveTerrain, caveTerrain ? TerraBlenderBiomes.nether(server.registryAccess()) : List.of(),
@@ -455,7 +455,7 @@ public final class AgeDimensionService {
             AgeDefinition age,
             AgeRuntimeProfile profile
     ) {
-        if (age.generationVersion() < AgeDefinition.CURRENT_GENERATION_VERSION) {
+        if (age.generationVersion() < AgeDefinition.LEGACY_GENERATOR_CUTOFF) {
             return legacyBiomeSource(server, age, profile);
         }
         AgeBiomeSelection selection = age.plan() != null && age.plan().biomeSelection() != null
@@ -558,7 +558,9 @@ public final class AgeDimensionService {
         DimensionType base = server.registryAccess().lookupOrThrow(Registries.DIMENSION_TYPE)
                 .getOrThrow(ResourceKey.create(Registries.DIMENSION_TYPE, profile.dimensionType())).value();
         AgeTraits.Lighting lighting = age.traits().lighting();
-        boolean hasSkyLight = base.hasSkyLight() && lighting != AgeTraits.Lighting.DARK;
+        AgeSkyProfile sky = AgeSkyProfile.forAge(age);
+        boolean hasSkyLight = (base.hasSkyLight() || !sky.bodies().isEmpty())
+                && lighting != AgeTraits.Lighting.DARK && !age.caveTerrain();
         float ambientLight = lighting == AgeTraits.Lighting.BRIGHT ? 0.25F : 0.0F;
         return new DimensionType(
                 base.fixedTime(),
@@ -573,7 +575,9 @@ public final class AgeDimensionService {
                 base.height(),
                 base.logicalHeight(),
                 base.infiniburn(),
-                AgeEnvironmentCompiler.skyEffects(age.plan(), base.effectsLocation()),
+                age.plan() == null && sky.custom()
+                        ? AgeEnvironmentCompiler.CUSTOM_SKY_EFFECTS
+                        : AgeEnvironmentCompiler.skyEffects(age.plan(), base.effectsLocation()),
                 ambientLight,
                 base.monsterSettings()
         );

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

@@ -2,10 +2,16 @@ package net.dnorberg.rivencraft.book;
 
 import net.dnorberg.rivencraft.writing.SymbolSemantics;
 import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.resources.ResourceKey;
 import net.minecraft.world.level.dimension.BuiltinDimensionTypes;
 
 /** Resolves written environment pages without changing the seeded page-free Age path. */
 public final class AgeEnvironmentCompiler {
+    public static final ResourceLocation CUSTOM_SKY_EFFECTS = ResourceLocation.fromNamespaceAndPath(
+            "rivencraft", "custom_sky");
     private AgeEnvironmentCompiler() {}
 
     public static AgeTraits apply(AgeGenerationPlan plan, AgeTraits seeded) {
@@ -19,6 +25,7 @@ public final class AgeEnvironmentCompiler {
         } else {
             applied = applyLegacy(plan, seeded);
         }
+        AgeSkyProfile.compile(plan, applied);
         return forTerrain(applied, plan.runtimeProfile());
     }
 
@@ -67,8 +74,7 @@ public final class AgeEnvironmentCompiler {
                     phaseDegrees = writtenPhase ? circularMidpoint(phaseDegrees, next) : next;
                     writtenPhase = true;
                 }
-                case ANGLE_MODIFIER -> throw new IllegalArgumentException(
+                case ANGLE_MODIFIER -> { } // Consumed by the next independently rendered celestial.
-                        "Sun angle pages require a custom sky renderer and are not supported yet");
                 default -> { }
             }
         }
@@ -81,6 +87,8 @@ public final class AgeEnvironmentCompiler {
     /** Vanilla effects are the sky styles the current renderer can honor exactly. */
     public static ResourceLocation skyEffects(AgeGenerationPlan plan, ResourceLocation fallback) {
         if (plan == null) return fallback;
+        if (skyColor(plan) != -1 || staticSky(plan) || AgeSkyProfile.hasCustomCelestials(plan))
+            return CUSTOM_SKY_EFFECTS;
         return plan.activeSymbols().stream()
                 .filter(symbol -> symbol.semantics().role() == SymbolSemantics.Role.SKY)
                 .map(symbol -> ((SymbolSemantics.ChoiceValue) symbol.semantics().value()).id())
@@ -92,6 +100,52 @@ public final class AgeEnvironmentCompiler {
                 }).findFirst().orElse(fallback);
     }
 
+    public static boolean staticSky(AgeGenerationPlan plan) {
+        return plan != null && plan.activeSymbols().stream().anyMatch(symbol ->
+                symbol.semantics().role() == SymbolSemantics.Role.SKY
+                        && ((SymbolSemantics.ChoiceValue) symbol.semantics().value()).id().equals("static"));
+    }
+
+    /** An authored color is fixed; -1 means the biome or selected vanilla sky supplies it. */
+    public static int skyColor(AgeGenerationPlan plan) {
+        if (plan == null) return -1;
+        return AgeSkyProfile.mixColors(plan.activeSymbols().stream()
+                .filter(symbol -> symbol.semantics().role() == SymbolSemantics.Role.SKY_COLOR)
+                .map(symbol -> ((SymbolSemantics.ChoiceValue) symbol.semantics().value()).id())
+                .map(AgeSkyProfile::color).toList());
+    }
+
+    public static int selectedSkyColor(AgeGenerationPlan plan, ResourceLocation fallback, int biomeSkyColor) {
+        int authored = skyColor(plan);
+        if (authored != -1) return authored;
+        if (staticSky(plan)) return 0xFF929292;
+        ResourceLocation effects = skyEffects(plan, fallback);
+        return previewSkyColor(effects, biomeSkyColor);
+    }
+
+    /** Shared server answer for book previews and the fallback crystal portal surface. */
+    public static int previewSkyColor(ServerLevel level, BlockPos origin) {
+        int biomeColor = level.getBiome(origin).value().getSkyColor();
+        var age = AgeRegistrySavedData.get(level).definitions().stream()
+                .filter(candidate -> AgeDimensionService.dimensionKey(candidate).equals(level.dimension()))
+                .findFirst();
+        if (age.isEmpty()) return previewSkyColor(level.dimensionType().effectsLocation(), biomeColor);
+        var definition = age.orElseThrow();
+        AgeSkyProfile sky = AgeSkyProfile.forAge(definition);
+        if (definition.plan() == null && definition.generationVersion() >= AgeSkyProfile.RANDOM_SKY_GENERATION_VERSION) {
+            if (sky.color() != -1) return sky.color();
+            if (sky.style() == AgeSkyProfile.Style.STATIC) return 0xFF929292;
+        }
+        var profile = definition.plan() == null
+                ? AgeRuntimeProfiles.resolve(definition.generationProfile())
+                : definition.plan().runtimeProfile();
+        ResourceLocation baseEffects = level.getServer().registryAccess()
+                .lookupOrThrow(Registries.DIMENSION_TYPE)
+                .getOrThrow(ResourceKey.create(Registries.DIMENSION_TYPE, profile.dimensionType()))
+                .value().effectsLocation();
+        return selectedSkyColor(definition.plan(), baseEffects, biomeColor);
+    }
+
     public static boolean hasWrittenPhase(AgeGenerationPlan plan) {
         if (plan == null) return false;
         if (plan.version() >= 4) return orderedCelestial(plan, null).writtenPhase();

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

@@ -188,7 +188,7 @@ public record AgeGenerationPlan(int version, long ageSeed, OrderedWriting writin
             String raw = item.getString("Value");
             SymbolSemantics.Value value = switch (role) {
                 case TERRAIN, BIOME, BLOCK, FEATURE -> new SymbolSemantics.ResourceValue(ResourceLocation.parse(raw));
-                case PERIOD_MODIFIER, ANGLE_MODIFIER, PHASE_MODIFIER ->
+                case PERIOD_MODIFIER, ANGLE_MODIFIER, PHASE_MODIFIER, SIZE_MODIFIER ->
                         new SymbolSemantics.NumberValue(Double.parseDouble(raw));
                 default -> new SymbolSemantics.ChoiceValue(raw);
             };

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

@@ -51,6 +51,10 @@ public record AgeInstability(int version, int score, List<Contribution> breakdow
     }
 
     static AgeInstability compute(AgeGenerationPlan plan, AgeTraits traits, RegistryAccess registries) {
+        return compute(plan, traits, registries, Long.MIN_VALUE);
+    }
+
+    static AgeInstability compute(AgeGenerationPlan plan, AgeTraits traits, RegistryAccess registries, long ageSeed) {
         Objects.requireNonNull(traits, "traits");
         List<Contribution> contributions = new ArrayList<>();
         if (plan == null) {
@@ -82,6 +86,17 @@ public record AgeInstability(int version, int score, List<Contribution> breakdow
             contributions.add(new Contribution("bright_lighting", -1, BRIGHT_LIGHTING_COST,
                     "Seeded bright lighting"));
         }
+        AgeSkyProfile sky = plan == null && ageSeed != Long.MIN_VALUE ? AgeSkyProfile.random(ageSeed, traits)
+                : plan == null ? new AgeSkyProfile(AgeSkyProfile.Style.INHERITED, -1, List.of())
+                : AgeSkyProfile.compile(plan, traits);
+        int seenSuns = 0;
+        for (AgeSkyProfile.Body body : sky.bodies()) {
+            if (body.kind() != AgeSkyProfile.Kind.SUN) continue;
+            if (++seenSuns <= 2) continue;
+            int points = 1000 * (seenSuns - 2);
+            contributions.add(new Contribution("extra_sun", -1, points,
+                    "Sun " + seenSuns + " adds growing instability"));
+        }
         return new AgeInstability(CURRENT_VERSION,
                 contributions.stream().mapToInt(Contribution::points).sum(), contributions);
     }
@@ -94,7 +109,8 @@ public record AgeInstability(int version, int score, List<Contribution> breakdow
             if (cave) {
                 var role = symbol.semantics().role();
                 if (switch (role) {
-                    case WEATHER, SEASON, CELESTIAL, PERIOD_MODIFIER, PHASE_MODIFIER, ANGLE_MODIFIER -> true;
+                    case WEATHER, SEASON, CELESTIAL, PERIOD_MODIFIER, PHASE_MODIFIER,
+                            ANGLE_MODIFIER, DIRECTION_MODIFIER -> true;
                     default -> false;
                 }) {
                     contributions.add(new Contribution("cave_ignored_" + role.id(), symbol.index(),

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

@@ -179,7 +179,7 @@ public final class AgeRegistrySavedData extends SavedData {
         AgeTraits effectiveTraits = plan == null
                 ? AgeEnvironmentCompiler.forTerrain(traits, AgeRuntimeProfiles.resolve(seedProfile))
                 : AgeEnvironmentCompiler.apply(plan, traits);
-        AgeInstability instability = AgeInstability.compute(plan, effectiveTraits, registries);
+        AgeInstability instability = AgeInstability.compute(plan, effectiveTraits, registries, seed);
         AgeInstabilityPlan instabilityPlan = AgeInstabilityPlan.select(instability, seed);
         AgeDefinition created = new AgeDefinition(
                 reference.id(),

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

@@ -0,0 +1,181 @@
+package net.dnorberg.rivencraft.book;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Random;
+import java.util.Set;
+import net.dnorberg.rivencraft.writing.SymbolSemantics;
+
+/** The ordered, deterministic sky specification for an Age. No client data is trusted here. */
+public record AgeSkyProfile(Style style, int color, List<Body> bodies) {
+    public static final int RANDOM_SKY_GENERATION_VERSION = 17;
+    private static final int[] COLORS = {0xB74A50, 0xD9834B, 0xDBC574, 0x5AAB80,
+            0x6FA8DF, 0x9870B9, 0xD5DBE1, 0x252531};
+
+    public AgeSkyProfile {
+        bodies = List.copyOf(bodies);
+        long suns = bodies.stream().filter(body -> body.kind() == Kind.SUN).count();
+        long moons = bodies.size() - suns;
+        if (suns > 10 || moons > 10) throw new IllegalArgumentException("An Age may have at most ten suns and ten moons");
+    }
+
+    public static AgeSkyProfile forAge(AgeDefinition age) {
+        if (age.plan() != null) return compile(age.plan(), age.traits());
+        if (age.generationVersion() >= RANDOM_SKY_GENERATION_VERSION)
+            return random(age.seed(), age.traits());
+        return new AgeSkyProfile(Style.INHERITED, -1, List.of());
+    }
+
+    public static AgeSkyProfile random(long seed, AgeTraits traits) {
+        Random random = new Random(seed ^ 0x534B5950524F464CL);
+        Style style = Style.values()[random.nextInt(Style.values().length)];
+        int color = randomColor(random);
+        int suns = random.nextInt(4);
+        int moons = random.nextInt(4);
+        List<Body> bodies = new ArrayList<>();
+        for (int i = 0; i < suns; i++)
+            bodies.add(new Body(Kind.SUN, randomColor(random),
+                    0.75F + random.nextFloat(), random.nextFloat() * 360.0F,
+                    traits.celestialPeriod(), random.nextFloat(), random.nextBoolean()));
+        for (int i = 0; i < moons; i++)
+            bodies.add(new Body(Kind.MOON, randomColor(random),
+                    0.75F + random.nextFloat(), random.nextFloat() * 360.0F,
+                    traits.celestialPeriod(), random.nextFloat(), random.nextBoolean()));
+        return new AgeSkyProfile(style, color, bodies);
+    }
+
+    public static AgeSkyProfile compile(AgeGenerationPlan plan, AgeTraits traits) {
+        if (plan == null) return new AgeSkyProfile(Style.INHERITED, -1, List.of());
+        Style style = Style.INHERITED;
+        int color = AgeEnvironmentCompiler.skyColor(plan);
+        boolean customBodies = hasCustomCelestials(plan);
+        List<Body> bodies = new ArrayList<>();
+        Set<Integer> active = new HashSet<>(plan.activeSymbolIndices());
+        AgeTraits seeded = AgeTraits.select(plan.ageSeed());
+        double period = 1.0D;
+        float angle = seeded.celestialAngle();
+        float phase = seeded.celestialPhase();
+        float size = 1.0F;
+        List<Integer> bodyColors = new ArrayList<>();
+        boolean clockwise = true;
+        for (AgeGenerationPlan.ResolvedSymbol symbol : plan.symbols()) {
+            if (!active.contains(symbol.index())) continue;
+            SymbolSemantics semantics = symbol.semantics();
+            switch (semantics.role()) {
+                case SKY -> style = switch (((SymbolSemantics.ChoiceValue) semantics.value()).id()) {
+                    case "overworld" -> Style.OVERWORLD;
+                    case "nether" -> Style.NETHER;
+                    case "end" -> Style.END;
+                    case "static" -> Style.STATIC;
+                    default -> throw new IllegalArgumentException("Unknown sky style");
+                };
+                case PERIOD_MODIFIER -> period = ((SymbolSemantics.NumberValue) semantics.value()).amount();
+                case ANGLE_MODIFIER -> angle = (float) ((SymbolSemantics.NumberValue) semantics.value()).amount();
+                case PHASE_MODIFIER -> phase = (float) (((SymbolSemantics.NumberValue) semantics.value()).amount() / 360.0D);
+                case SIZE_MODIFIER -> size = (float) ((SymbolSemantics.NumberValue) semantics.value()).amount();
+                case CELESTIAL_COLOR -> bodyColors.add(color(
+                        ((SymbolSemantics.ChoiceValue) semantics.value()).id()));
+                case DIRECTION_MODIFIER -> clockwise = ((SymbolSemantics.ChoiceValue) semantics.value())
+                        .id().equals("clockwise");
+                case CELESTIAL -> {
+                    String choice = ((SymbolSemantics.ChoiceValue) semantics.value()).id();
+                    int bodyColor = bodyColors.isEmpty() ? 0xFFFFFF : mixColors(bodyColors);
+                    if (choice.equals("normal_time")) {
+                        if (customBodies) {
+                            bodies.add(new Body(Kind.SUN, bodyColor, size, angle, period, phase, clockwise));
+                            bodies.add(new Body(Kind.MOON, bodyColor, 1.0F, angle, period,
+                                    (phase + 0.5F) % 1.0F, clockwise));
+                        }
+                    } else {
+                        bodies.add(new Body(choice.equals("sun") ? Kind.SUN : Kind.MOON,
+                                bodyColor, size, angle, period, phase, clockwise));
+                    }
+                    period = 1.0D;
+                    angle = seeded.celestialAngle();
+                    phase = seeded.celestialPhase();
+                    size = 1.0F;
+                    bodyColors.clear();
+                    clockwise = true;
+                }
+                default -> { }
+            }
+        }
+        // Missing branches are seed-completed, including the celestial branch.
+        // An explicit sky or sky-color page does not suppress that completion.
+        if (plan.activeSymbols().stream().noneMatch(symbol ->
+                symbol.semantics().role() == SymbolSemantics.Role.CELESTIAL)) {
+            bodies.addAll(random(plan.ageSeed(), seeded).bodies());
+        }
+        return new AgeSkyProfile(style, color, bodies);
+    }
+
+    public static int mixColors(List<Integer> colors) {
+        if (colors.isEmpty()) return -1;
+        long red = 0, green = 0, blue = 0;
+        for (int color : colors) {
+            red += color >> 16 & 255;
+            green += color >> 8 & 255;
+            blue += color & 255;
+        }
+        int count = colors.size();
+        return (int) ((red + count / 2) / count) << 16
+                | (int) ((green + count / 2) / count) << 8
+                | (int) ((blue + count / 2) / count);
+    }
+
+    private static int randomColor(Random random) {
+        int count = 1 + random.nextInt(3);
+        List<Integer> colors = new ArrayList<>(count);
+        for (int i = 0; i < count; i++) colors.add(COLORS[random.nextInt(COLORS.length)]);
+        return mixColors(colors);
+    }
+
+    public static boolean hasCustomCelestials(AgeGenerationPlan plan) {
+        return plan != null && plan.activeSymbols().stream().anyMatch(symbol ->
+                symbol.semantics().role() == SymbolSemantics.Role.CELESTIAL
+                        && !((SymbolSemantics.ChoiceValue) symbol.semantics().value()).id().equals("normal_time")
+                        || symbol.semantics().role() == SymbolSemantics.Role.CELESTIAL_COLOR
+                        || symbol.semantics().role() == SymbolSemantics.Role.SIZE_MODIFIER
+                        || symbol.semantics().role() == SymbolSemantics.Role.DIRECTION_MODIFIER);
+    }
+
+    public boolean custom() {
+        return style == Style.STATIC || color != -1 || !bodies.isEmpty();
+    }
+
+    /** Vanilla has one skylight channel; combine visible bodies into that channel. */
+    public float lightAt(double dayTime) {
+        float sunlight = 0.0F;
+        float moonlight = 0.0F;
+        for (Body body : bodies) {
+            double orbit = body.period() == 0.0D ? body.phase()
+                    : (body.clockwise() ? 1.0D : -1.0D) * dayTime
+                            / (24000.0D * body.period()) + body.phase();
+            float altitude = (float) Math.cos(orbit * Math.PI * 2.0D);
+            if (altitude <= 0.0F) continue;
+            if (body.kind() == Kind.SUN) sunlight += altitude;
+            else moonlight += altitude * 0.18F;
+        }
+        return Math.min(1.0F, sunlight > 0.0F ? sunlight : moonlight);
+    }
+
+    public static int color(String name) {
+        return switch (name) {
+            case "red" -> COLORS[0];
+            case "orange" -> COLORS[1];
+            case "yellow" -> COLORS[2];
+            case "green" -> COLORS[3];
+            case "blue" -> COLORS[4];
+            case "purple" -> COLORS[5];
+            case "white" -> COLORS[6];
+            case "black" -> COLORS[7];
+            default -> throw new IllegalArgumentException("Unknown sky color " + name);
+        };
+    }
+
+    public enum Style { INHERITED, OVERWORLD, NETHER, END, STATIC }
+    public enum Kind { SUN, MOON }
+    public record Body(Kind kind, int color, float size, float angle,
+                       double period, float phase, boolean clockwise) { }
+}

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

@@ -52,9 +52,11 @@ public final class EnvironmentWritingGameTests {
     public static void environmentPagesEnterCreativeAndJeiFeed(GameTestHelper helper) {
         Set<String> expected = Set.of(
                 "lighting/normal", "lighting/dark", "lighting/bright",
-                "sky/overworld", "sky/nether", "sky/end",
+                "sky/overworld", "sky/nether", "sky/end", "sky/static", "sky_color/purple",
                 "weather/normal", "weather/fast", "weather/slow", "weather/off",
-                "weather/always", "weather/storm", "celestial/normal_time",
+                "weather/always", "weather/storm", "celestial/normal_time", "celestial/sun",
+                "celestial/moon", "celestial_color/red", "size/large", "angle/east",
+                "direction/clockwise", "direction/counterclockwise",
                 "season/no_seasons", "season/seasons", "season/eternal_winter",
                 "season/eternal_summer", "season/eternal_fall", "season/eternal_spring",
                 "period/zero", "period/half", "period/full", "period/double",
@@ -135,6 +137,104 @@ public final class EnvironmentWritingGameTests {
         helper.succeed();
     }
 
+    @GameTest(template = "empty")
+    public static void authoredStaticSkyColorSurvivesWritingAndFeedsPreview(GameTestHelper helper) {
+        OrderedWriting writing = new OrderedWriting(List.of(
+                WritingEntry.linkPanel(), page("terrain/standard"), page("sky/static"),
+                page("sky_color/purple"), page("celestial/normal_time")));
+        AgeTraits seeded = AgeTraits.select(44L);
+        AgeGenerationPlan plan = AgeGenerationPlan.compile(writing, 44L, AgeGenerationProfiles.STANDARD,
+                seeded, helper.getLevel().registryAccess());
+        helper.assertTrue(AgeEnvironmentCompiler.staticSky(plan),
+                "The authored Static Sky page must survive Age compilation");
+        helper.assertValueEqual(AgeEnvironmentCompiler.skyEffects(plan, BuiltinDimensionTypes.OVERWORLD_EFFECTS),
+                AgeEnvironmentCompiler.CUSTOM_SKY_EFFECTS,
+                "The static sky must select Rivencraft's custom renderer");
+        helper.assertValueEqual(AgeEnvironmentCompiler.selectedSkyColor(plan,
+                        BuiltinDimensionTypes.OVERWORLD_EFFECTS, 0xFF77AAFF),
+                0x9870B9, "The authored color must tint the sky and preview consistently");
+        AgeGenerationPlan restored = AgeGenerationPlan.load(plan.save());
+        helper.assertTrue(AgeEnvironmentCompiler.staticSky(restored),
+                "A saved Age must retain its static sky choice");
+        helper.assertValueEqual(AgeEnvironmentCompiler.skyColor(restored), 0x9870B9,
+                "A saved Age must retain its sky color choice");
+        AgeGenerationPlan coloredEnd = AgeGenerationPlan.compile(new OrderedWriting(List.of(
+                        WritingEntry.linkPanel(), page("terrain/standard"), page("sky/end"),
+                        page("sky_color/red"), page("celestial/normal_time"))),
+                45L, AgeGenerationProfiles.STANDARD, AgeTraits.select(45L),
+                helper.getLevel().registryAccess());
+        helper.assertValueEqual(AgeEnvironmentCompiler.skyEffects(coloredEnd,
+                        BuiltinDimensionTypes.OVERWORLD_EFFECTS),
+                AgeEnvironmentCompiler.CUSTOM_SKY_EFFECTS,
+                "A color page must make non-Overworld skies renderable by the custom sky effect");
+        helper.assertValueEqual(AgeEnvironmentCompiler.selectedSkyColor(coloredEnd,
+                        BuiltinDimensionTypes.OVERWORLD_EFFECTS, 0xFF77AAFF),
+                0xB74A50, "A color page must override the selected sky type's default tint");
+        helper.assertTrue(PageItem.bundledCreativeSymbols().contains("sky/static")
+                        && PageItem.bundledCreativeSymbols().contains("sky_color/purple"),
+                "New sky pages must be available through the Creative and JEI page catalog");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void skyAndCelestialColorsBlendWithoutRequiringBodies(GameTestHelper helper) {
+        OrderedWriting writing = new OrderedWriting(List.of(
+                WritingEntry.linkPanel(), page("terrain/standard"), page("sky/overworld"),
+                page("sky_color/red"), page("sky_color/blue"),
+                page("celestial_color/yellow"), page("celestial_color/blue"), page("celestial/sun")));
+        helper.assertTrue(WritingGrammar.parse(writing).canCreate(),
+                "Two sky colors and two colors for one sun must be valid writing");
+        AgeTraits traits = AgeTraits.select(46L);
+        AgeGenerationPlan plan = AgeGenerationPlan.compile(writing, 46L,
+                AgeGenerationProfiles.STANDARD, traits, helper.getLevel().registryAccess());
+        int skyColor = AgeSkyProfile.mixColors(List.of(
+                AgeSkyProfile.color("red"), AgeSkyProfile.color("blue")));
+        int sunColor = AgeSkyProfile.mixColors(List.of(
+                AgeSkyProfile.color("yellow"), AgeSkyProfile.color("blue")));
+        helper.assertValueEqual(AgeEnvironmentCompiler.skyColor(plan), skyColor,
+                "Sky color pages must blend without discarding either page");
+        AgeSkyProfile profile = AgeSkyProfile.compile(plan, traits);
+        helper.assertValueEqual(profile.bodies().size(), 1, "The written Age has exactly one sun");
+        helper.assertValueEqual(profile.bodies().getFirst().color(), sunColor,
+                "Celestial colors must blend for the following body");
+        helper.assertValueEqual(AgeSkyProfile.compile(AgeGenerationPlan.load(plan.save()), traits), profile,
+                "Blended colors must survive the saved writing plan");
+
+        AgeSkyProfile bodyless = new AgeSkyProfile(AgeSkyProfile.Style.OVERWORLD, skyColor, List.of());
+        helper.assertTrue(bodyless.custom() && bodyless.bodies().isEmpty(),
+                "An Age can have an authored sky without any celestial bodies");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void randomAndAuthoredCelestialsKeepIndependentOrbits(GameTestHelper helper) {
+        AgeTraits traits = AgeTraits.select(12345L);
+        AgeSkyProfile first = AgeSkyProfile.random(12345L, traits);
+        helper.assertValueEqual(first, AgeSkyProfile.random(12345L, traits),
+                "A random Age must recreate the same sky from its saved seed");
+        helper.assertTrue(first.bodies().stream().filter(body -> body.kind() == AgeSkyProfile.Kind.SUN).count() <= 10
+                        && first.bodies().stream().filter(body -> body.kind() == AgeSkyProfile.Kind.MOON).count() <= 10,
+                "Random Ages must obey the same celestial limits as authored Ages");
+        OrderedWriting writing = new OrderedWriting(List.of(
+                WritingEntry.linkPanel(), page("terrain/standard"), page("sky/end"),
+                page("angle/east"), page("direction/counterclockwise"), page("celestial_color/red"),
+                page("size/large"), page("period/half"), page("celestial/sun"),
+                page("direction/clockwise"), page("celestial/moon")));
+        AgeGenerationPlan plan = AgeGenerationPlan.compile(writing, 12345L, AgeGenerationProfiles.STANDARD,
+                traits, helper.getLevel().registryAccess());
+        AgeSkyProfile sky = AgeSkyProfile.compile(plan, AgeEnvironmentCompiler.apply(plan, traits));
+        helper.assertValueEqual(sky.bodies().size(), 2, "Both written celestial bodies must be retained");
+        helper.assertValueEqual(sky.bodies().getFirst().angle(), 90.0F,
+                "The first body's compass angle must be independent");
+        helper.assertFalse(sky.bodies().getFirst().clockwise(),
+                "The first body should move counterclockwise");
+        helper.assertTrue(sky.bodies().getLast().clockwise(),
+                "The second body should move clockwise");
+        helper.assertValueEqual(AgeSkyProfile.compile(AgeGenerationPlan.load(plan.save()), traits), sky,
+                "Body angle and direction must survive Age-plan serialization");
+        helper.succeed();
+    }
+
     @GameTest(template = "empty")
     public static void writtenEnvironmentPersistsAndPageFreeAgesStaySeeded(GameTestHelper helper) {
         OrderedWriting writing = new OrderedWriting(List.of(

src/main/java/net/dnorberg/rivencraft/client/ClientAgeCelestialAngles.java

@@ -2,23 +2,58 @@ package net.dnorberg.rivencraft.client;
 
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import net.dnorberg.rivencraft.book.AgeSkyProfile;
 import net.dnorberg.rivencraft.network.AgeCelestialAnglePayload;
 import net.minecraft.resources.ResourceKey;
 import net.minecraft.world.level.Level;
 import net.neoforged.neoforge.network.handling.IPayloadContext;
+import net.neoforged.neoforge.network.PacketDistributor;
+import net.dnorberg.rivencraft.network.RequestAgeSkyPayload;
 
 /** Client cache used by both the active world and remote preview renderers. */
 public final class ClientAgeCelestialAngles {
     private static final Map<ResourceKey<Level>, Float> ANGLES = new ConcurrentHashMap<>();
+    private static final Map<ResourceKey<Level>, AgeSkyProfile> SKIES = new ConcurrentHashMap<>();
+    private static final Map<ResourceKey<Level>, Long> LAST_REQUEST = new ConcurrentHashMap<>();
 
     private ClientAgeCelestialAngles() {
     }
 
     public static void handle(AgeCelestialAnglePayload payload, IPayloadContext context) {
         ANGLES.put(payload.dimension(), payload.angle());
+        SKIES.put(payload.dimension(), payload.sky());
+        LAST_REQUEST.remove(payload.dimension());
+    }
+
+    public static void requestIfMissing(ResourceKey<Level> dimension) {
+        if (!dimension.location().getNamespace().equals("rivencraft") || SKIES.containsKey(dimension)) return;
+        long now = System.nanoTime();
+        Long previous = LAST_REQUEST.putIfAbsent(dimension, now);
+        if (previous != null && now - previous < 2_000_000_000L) return;
+        LAST_REQUEST.put(dimension, now);
+        PacketDistributor.sendToServer(new RequestAgeSkyPayload(dimension));
+    }
+
+    public static void clear() {
+        ANGLES.clear();
+        SKIES.clear();
+        LAST_REQUEST.clear();
     }
 
     public static float get(ResourceKey<Level> dimension) {
         return ANGLES.getOrDefault(dimension, 0.0F);
     }
+
+    public static int skyColor(ResourceKey<Level> dimension) {
+        return sky(dimension).color();
+    }
+
+    public static boolean staticSky(ResourceKey<Level> dimension) {
+        return sky(dimension).style() == AgeSkyProfile.Style.STATIC;
+    }
+
+    public static AgeSkyProfile sky(ResourceKey<Level> dimension) {
+        return SKIES.getOrDefault(dimension,
+                new AgeSkyProfile(AgeSkyProfile.Style.INHERITED, -1, java.util.List.of()));
+    }
 }

src/main/java/net/dnorberg/rivencraft/client/ClientEvents.java

@@ -19,6 +19,12 @@ import net.neoforged.neoforge.common.NeoForge;
 import net.neoforged.neoforge.client.event.EntityRenderersEvent;
 import net.neoforged.neoforge.client.event.RegisterMenuScreensEvent;
 import net.neoforged.neoforge.client.event.RegisterClientReloadListenersEvent;
+import net.neoforged.neoforge.client.event.RegisterDimensionSpecialEffectsEvent;
+import net.neoforged.neoforge.client.event.RegisterColorHandlersEvent;
+import net.neoforged.neoforge.client.event.ClientPlayerNetworkEvent;
+import net.dnorberg.rivencraft.block.entity.CrystalPortalBlockEntity;
+import net.dnorberg.rivencraft.block.entity.BookReceptacleBlockEntity;
+import net.dnorberg.rivencraft.book.AgeEnvironmentCompiler;
 import net.neoforged.neoforge.client.extensions.common.IClientItemExtensions;
 import net.neoforged.neoforge.client.extensions.common.RegisterClientExtensionsEvent;
 import net.minecraft.client.renderer.BlockEntityWithoutLevelRenderer;
@@ -43,6 +49,23 @@ public final class ClientEvents {
         event.registerBlockEntityRenderer(ModBlockEntities.STAR_FISSURE.get(), StarFissureRenderer::new);
     }
 
+    @SubscribeEvent
+    public static void registerSkyEffects(RegisterDimensionSpecialEffectsEvent event) {
+        event.register(AgeEnvironmentCompiler.CUSTOM_SKY_EFFECTS, new RivencraftSkyEffects());
+    }
+
+    @SubscribeEvent
+    public static void registerPortalColor(RegisterColorHandlersEvent.Block event) {
+        event.register((state, level, pos, tintIndex) -> {
+            if (level == null || pos == null || tintIndex != 0
+                    || !(level.getBlockEntity(pos) instanceof CrystalPortalBlockEntity portal)
+                    || portal.receptacle() == null
+                    || !(level.getBlockEntity(portal.receptacle()) instanceof BookReceptacleBlockEntity holder)
+                    || holder.destination() == null) return 0xFFFFFF;
+            return holder.skyColor();
+        }, ModBlocks.CRYSTAL_PORTAL.get());
+    }
+
     @SubscribeEvent
     public static void registerScreens(RegisterMenuScreensEvent event) {
         event.register(ModMenus.NOTEBOOK.get(), NotebookScreen::new);
@@ -99,6 +122,11 @@ public final class ClientEvents {
         NeoForge.EVENT_BUS.addListener(ClientBookExploreOverlay::onClientTickPost);
         NeoForge.EVENT_BUS.addListener(ClientBookExploreOverlay::onRenderGui);
         NeoForge.EVENT_BUS.addListener(ClientBookExploreOverlay::onMouseButton);
+        NeoForge.EVENT_BUS.addListener(ClientEvents::onLogout);
+    }
+
+    private static void onLogout(ClientPlayerNetworkEvent.LoggingOut event) {
+        ClientAgeCelestialAngles.clear();
     }
 
 }

src/main/java/net/dnorberg/rivencraft/client/RivencraftSkyEffects.java

@@ -0,0 +1,145 @@
+package net.dnorberg.rivencraft.client;
+
+import com.mojang.blaze3d.systems.RenderSystem;
+import com.mojang.blaze3d.vertex.BufferBuilder;
+import com.mojang.blaze3d.vertex.BufferUploader;
+import com.mojang.blaze3d.vertex.DefaultVertexFormat;
+import com.mojang.blaze3d.vertex.PoseStack;
+import com.mojang.blaze3d.vertex.Tesselator;
+import com.mojang.blaze3d.vertex.VertexFormat;
+import java.util.Random;
+import net.dnorberg.rivencraft.book.AgeSkyProfile;
+import net.minecraft.client.Camera;
+import net.minecraft.client.multiplayer.ClientLevel;
+import net.minecraft.client.renderer.DimensionSpecialEffects;
+import net.minecraft.client.renderer.FogRenderer;
+import net.minecraft.client.renderer.GameRenderer;
+import net.minecraft.world.phys.Vec3;
+import org.joml.Matrix4f;
+import com.mojang.math.Axis;
+import net.minecraft.resources.ResourceLocation;
+
+/** An authored sky can use vanilla celestial rendering or Legacy-style moving TV static. */
+public final class RivencraftSkyEffects extends DimensionSpecialEffects {
+    private static final int GRID = 16;
+    private static final float RADIUS = 100.0F;
+    private static final ResourceLocation SUN = ResourceLocation.withDefaultNamespace("textures/environment/sun.png");
+    private static final ResourceLocation MOON = ResourceLocation.withDefaultNamespace("textures/environment/moon_phases.png");
+
+    public RivencraftSkyEffects() {
+        super(192.0F, true, SkyType.NORMAL, false, false);
+    }
+
+    @Override
+    public Vec3 getBrightnessDependentFogColor(Vec3 color, float brightness) {
+        return color.multiply(brightness * 0.94F + 0.06F,
+                brightness * 0.94F + 0.06F, brightness * 0.91F + 0.09F);
+    }
+
+    @Override
+    public boolean isFoggyAt(int x, int y) {
+        return false;
+    }
+
+    @Override
+    public boolean renderSky(ClientLevel level, int ticks, float partialTick, Matrix4f modelViewMatrix,
+                             Camera camera, Matrix4f projectionMatrix, boolean isFoggy, Runnable setupFog) {
+        AgeSkyProfile sky = ClientAgeCelestialAngles.sky(level.dimension());
+        if (sky.style() != AgeSkyProfile.Style.STATIC && sky.color() == -1 && sky.bodies().isEmpty()
+                && sky.style() != AgeSkyProfile.Style.NETHER && sky.style() != AgeSkyProfile.Style.END)
+            return false;
+        setupFog.run();
+        if (isFoggy) return true;
+
+        PoseStack pose = new PoseStack();
+        pose.mulPose(modelViewMatrix);
+        Matrix4f matrix = pose.last().pose();
+        Random random = new Random((level.getGameTime() + (long) ticks) / 2L);
+        int tint = sky.color();
+        if (tint == -1) tint = switch (sky.style()) {
+            case NETHER -> 0x6B2725;
+            case END -> 0x211835;
+            case STATIC -> 0x929292;
+            default -> level.getBiome(camera.getBlockPosition()).value().getSkyColor();
+        };
+
+        RenderSystem.depthMask(false);
+        RenderSystem.disableCull();
+        RenderSystem.setShader(GameRenderer::getPositionColorShader);
+        RenderSystem.setShaderColor(1.0F, 1.0F, 1.0F, 1.0F);
+        FogRenderer.setupNoFog();
+        BufferBuilder vertices = Tesselator.getInstance().begin(
+                VertexFormat.Mode.QUADS, DefaultVertexFormat.POSITION_COLOR);
+        for (int axis = 0; axis < 3; axis++) {
+            for (int sign : new int[]{-1, 1}) {
+                for (int x = 0; x < GRID; x++) {
+                    for (int y = 0; y < GRID; y++) {
+                        int noise = sky.style() == AgeSkyProfile.Style.STATIC
+                                ? 65 + random.nextInt(160) : 255;
+                        int red = ((tint >> 16) & 255) * noise / 255;
+                        int green = ((tint >> 8) & 255) * noise / 255;
+                        int blue = (tint & 255) * noise / 255;
+                        int color = 0xFF000000 | red << 16 | green << 8 | blue;
+                        float left = -RADIUS + x * (2 * RADIUS / GRID);
+                        float right = -RADIUS + (x + 1) * (2 * RADIUS / GRID);
+                        float bottom = -RADIUS + y * (2 * RADIUS / GRID);
+                        float top = -RADIUS + (y + 1) * (2 * RADIUS / GRID);
+                        vertex(vertices, matrix, axis, sign, left, bottom, color);
+                        vertex(vertices, matrix, axis, sign, right, bottom, color);
+                        vertex(vertices, matrix, axis, sign, right, top, color);
+                        vertex(vertices, matrix, axis, sign, left, top, color);
+                    }
+                }
+            }
+        }
+        BufferUploader.drawWithShader(vertices.buildOrThrow());
+        if (!sky.bodies().isEmpty()) {
+            RenderSystem.enableBlend();
+            RenderSystem.defaultBlendFunc();
+            double time = level.getGameTime() + partialTick;
+            for (AgeSkyProfile.Body body : sky.bodies()) drawBody(pose, body, time);
+            RenderSystem.disableBlend();
+        }
+        setupFog.run();
+        RenderSystem.enableCull();
+        RenderSystem.depthMask(true);
+        return true;
+    }
+
+    private static void drawBody(PoseStack pose, AgeSkyProfile.Body body, double time) {
+        pose.pushPose();
+        pose.mulPose(Axis.YP.rotationDegrees(body.angle()));
+        double orbit = body.period() == 0 ? body.phase()
+                : (body.clockwise() ? 1.0D : -1.0D) * time
+                        / (24000.0D * body.period()) + body.phase();
+        pose.mulPose(Axis.XP.rotationDegrees((float) (orbit * 360.0D)));
+        float size = (body.kind() == AgeSkyProfile.Kind.SUN ? 30.0F : 20.0F) * body.size();
+        int color = body.color();
+        RenderSystem.setShader(GameRenderer::getPositionTexShader);
+        RenderSystem.setShaderTexture(0, body.kind() == AgeSkyProfile.Kind.SUN ? SUN : MOON);
+        RenderSystem.setShaderColor(((color >> 16) & 255) / 255.0F,
+                ((color >> 8) & 255) / 255.0F, (color & 255) / 255.0F, 1.0F);
+        float uMax = body.kind() == AgeSkyProfile.Kind.SUN ? 1.0F : 0.25F;
+        float vMax = body.kind() == AgeSkyProfile.Kind.SUN ? 1.0F : 0.5F;
+        BufferBuilder vertices = Tesselator.getInstance().begin(VertexFormat.Mode.QUADS,
+                DefaultVertexFormat.POSITION_TEX);
+        Matrix4f matrix = pose.last().pose();
+        vertices.addVertex(matrix, -size, RADIUS - 1.0F, -size).setUv(0.0F, 0.0F);
+        vertices.addVertex(matrix, size, RADIUS - 1.0F, -size).setUv(uMax, 0.0F);
+        vertices.addVertex(matrix, size, RADIUS - 1.0F, size).setUv(uMax, vMax);
+        vertices.addVertex(matrix, -size, RADIUS - 1.0F, size).setUv(0.0F, vMax);
+        BufferUploader.drawWithShader(vertices.buildOrThrow());
+        RenderSystem.setShaderColor(1.0F, 1.0F, 1.0F, 1.0F);
+        pose.popPose();
+    }
+
+    private static void vertex(BufferBuilder vertices, Matrix4f matrix, int axis, int sign,
+                               float x, float y, int color) {
+        float fixed = sign * RADIUS;
+        switch (axis) {
+            case 0 -> vertices.addVertex(matrix, fixed, x, y).setColor(color);
+            case 1 -> vertices.addVertex(matrix, x, fixed, y).setColor(color);
+            default -> vertices.addVertex(matrix, x, y, fixed).setColor(color);
+        }
+    }
+}

src/main/java/net/dnorberg/rivencraft/event/AgeCelestialAngleSync.java

@@ -3,11 +3,11 @@ package net.dnorberg.rivencraft.event;
 import net.dnorberg.rivencraft.book.AgeDefinition;
 import net.dnorberg.rivencraft.book.AgeDimensionService;
 import net.dnorberg.rivencraft.book.AgeRegistrySavedData;
+import net.dnorberg.rivencraft.book.AgeSkyProfile;
 import net.dnorberg.rivencraft.network.AgeCelestialAnglePayload;
 import net.minecraft.server.level.ServerPlayer;
 import net.neoforged.neoforge.event.entity.player.PlayerEvent;
 import net.neoforged.neoforge.network.PacketDistributor;
-import net.neoforged.neoforge.network.registration.NetworkRegistry;
 
 /** Sends saved celestial angles when a client joins or enters an Age. */
 public final class AgeCelestialAngleSync {
@@ -34,10 +34,8 @@ public final class AgeCelestialAngleSync {
     }
 
     public static void send(ServerPlayer player, AgeDefinition age) {
-        if (!NetworkRegistry.hasChannel(player.connection, AgeCelestialAnglePayload.TYPE.id())) {
-            return;
-        }
         PacketDistributor.sendToPlayer(player, new AgeCelestialAnglePayload(
-                AgeDimensionService.dimensionKey(age), age.traits().celestialAngle()));
+                AgeDimensionService.dimensionKey(age), age.traits().celestialAngle(),
+                AgeSkyProfile.forAge(age)));
     }
 }

src/main/java/net/dnorberg/rivencraft/mixin/LevelSkyBrightnessMixin.java

@@ -0,0 +1,40 @@
+package net.dnorberg.rivencraft.mixin;
+
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.book.AgeDimensionService;
+import net.dnorberg.rivencraft.book.AgeRegistrySavedData;
+import net.dnorberg.rivencraft.book.AgeSkyProfile;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.world.level.Level;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+/** Combines multiple celestial light sources into Minecraft's one skylight channel. */
+@Mixin(Level.class)
+public abstract class LevelSkyBrightnessMixin {
+    @Shadow private int skyDarken;
+
+    @Inject(method = "updateSkyBrightness", at = @At("TAIL"))
+    private void rivencraft$stackCelestialLight(CallbackInfo callback) {
+        if (!((Object) this instanceof ServerLevel level) || !level.dimensionType().hasSkyLight()) return;
+        // ServerLevel updates sky brightness in its constructor, before the
+        // MinecraftServer has registered even the Overworld level. Only an
+        // established Rivencraft Age can have a saved celestial profile.
+        if (!level.dimension().location().getNamespace().equals(Rivencraft.MOD_ID)
+                || !level.dimension().location().getPath().startsWith("age/")
+                || level.getServer().overworld() == null) return;
+        AgeRegistrySavedData.get(level).definitions().stream()
+                .filter(age -> AgeDimensionService.dimensionKey(age).equals(level.dimension()))
+                .findFirst().ifPresent(age -> {
+                    AgeSkyProfile sky = AgeSkyProfile.forAge(age);
+                    if (sky.bodies().isEmpty()) return;
+                    float light = sky.lightAt(level.getDayTime());
+                    float weather = (1.0F - level.getRainLevel(1.0F) * 5.0F / 16.0F)
+                            * (1.0F - level.getThunderLevel(1.0F) * 5.0F / 16.0F);
+                    skyDarken = (int) ((1.0F - light * weather) * 11.0F);
+                });
+    }
+}

src/main/java/net/dnorberg/rivencraft/mixin/client/ClientLevelSkyColorMixin.java

@@ -0,0 +1,40 @@
+package net.dnorberg.rivencraft.mixin.client;
+
+import net.dnorberg.rivencraft.client.ClientAgeCelestialAngles;
+import net.dnorberg.rivencraft.book.AgeSkyProfile;
+import net.minecraft.client.multiplayer.ClientLevel;
+import net.minecraft.world.phys.Vec3;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+/** Keeps authored color pages visible in the sky without replacing vanilla sun and stars. */
+@Mixin(ClientLevel.class)
+public abstract class ClientLevelSkyColorMixin {
+    @Inject(method = "getSkyColor", at = @At("RETURN"), cancellable = true)
+    private void rivencraft$colorAuthoredSky(Vec3 position, float partialTick,
+                                             CallbackInfoReturnable<Vec3> result) {
+        ClientLevel level = (ClientLevel) (Object) this;
+        int color = ClientAgeCelestialAngles.skyColor(level.dimension());
+        if (color == -1 || ClientAgeCelestialAngles.staticSky(level.dimension())) return;
+        Vec3 natural = result.getReturnValue();
+        // Retain the vanilla day/night and precipitation darkening while replacing its hue.
+        AgeSkyProfile sky = ClientAgeCelestialAngles.sky(level.dimension());
+        double brightness = sky.bodies().isEmpty()
+                ? Math.max(natural.x, Math.max(natural.y, natural.z))
+                : Math.max(0.08D, sky.lightAt(level.getDayTime() + partialTick));
+        result.setReturnValue(Vec3.fromRGB24(color).scale(brightness));
+    }
+
+    @Inject(method = "getSkyDarken", at = @At("RETURN"), cancellable = true)
+    private void rivencraft$stackClientCelestialLight(float partialTick,
+                                                       CallbackInfoReturnable<Float> result) {
+        ClientLevel level = (ClientLevel) (Object) this;
+        AgeSkyProfile sky = ClientAgeCelestialAngles.sky(level.dimension());
+        if (sky.bodies().isEmpty() || !level.dimensionType().hasSkyLight()) return;
+        float weather = (1.0F - level.getRainLevel(partialTick) * 5.0F / 16.0F)
+                * (1.0F - level.getThunderLevel(partialTick) * 5.0F / 16.0F);
+        result.setReturnValue(0.2F + 0.8F * sky.lightAt(level.getDayTime() + partialTick) * weather);
+    }
+}

src/main/java/net/dnorberg/rivencraft/mixin/client/LevelRendererMixin.java

@@ -2,20 +2,37 @@ package net.dnorberg.rivencraft.mixin.client;
 
 import com.mojang.math.Axis;
 import net.dnorberg.rivencraft.client.ClientAgeCelestialAngles;
+import net.dnorberg.rivencraft.client.RivencraftSkyEffects;
+import net.minecraft.client.Camera;
 import net.minecraft.client.multiplayer.ClientLevel;
 import net.minecraft.client.renderer.LevelRenderer;
+import org.joml.Matrix4f;
 import org.joml.Quaternionf;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Shadow;
 import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.Redirect;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 
 /** Rotates the vanilla sun, moon, and star path by each Age's saved angle. */
 @Mixin(LevelRenderer.class)
 public abstract class LevelRendererMixin {
+    private static final RivencraftSkyEffects RIVENCRAFT_SKY = new RivencraftSkyEffects();
+
     @Shadow
     private ClientLevel level;
 
+    @Inject(method = "renderSky", at = @At("HEAD"), cancellable = true)
+    private void rivencraft$renderAgeSky(Matrix4f frustumMatrix, Matrix4f projectionMatrix,
+                                        float partialTick, Camera camera, boolean isFoggy,
+                                        Runnable skyFogSetup, CallbackInfo callback) {
+        if (!level.dimension().location().getNamespace().equals("rivencraft")) return;
+        ClientAgeCelestialAngles.requestIfMissing(level.dimension());
+        if (RIVENCRAFT_SKY.renderSky(level, (int) level.getGameTime(), partialTick,
+                frustumMatrix, camera, projectionMatrix, isFoggy, skyFogSetup)) callback.cancel();
+    }
+
     @Redirect(
             method = "renderSky",
             at = @At(

src/main/java/net/dnorberg/rivencraft/network/AgeCelestialAnglePayload.java

@@ -1,6 +1,7 @@
 package net.dnorberg.rivencraft.network;
 
 import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.book.AgeSkyProfile;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.network.RegistryFriendlyByteBuf;
 import net.minecraft.network.codec.StreamCodec;
@@ -9,8 +10,8 @@ import net.minecraft.resources.ResourceKey;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.world.level.Level;
 
-/** Synchronizes an Age's saved celestial-plane rotation to clients. */
+/** Synchronizes an Age's saved celestial-plane rotation and authored sky to clients. */
-public record AgeCelestialAnglePayload(ResourceKey<Level> dimension, float angle)
+public record AgeCelestialAnglePayload(ResourceKey<Level> dimension, float angle, AgeSkyProfile sky)
         implements CustomPacketPayload {
     public static final Type<AgeCelestialAnglePayload> TYPE = new Type<>(
             ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "age_celestial_angle")
@@ -20,9 +21,34 @@ public record AgeCelestialAnglePayload(ResourceKey<Level> dimension, float angle
                     (buffer, payload) -> {
                         buffer.writeResourceKey(payload.dimension());
                         buffer.writeFloat(payload.angle());
+                        buffer.writeEnum(payload.sky().style());
+                        buffer.writeInt(payload.sky().color());
+                        buffer.writeVarInt(payload.sky().bodies().size());
+                        for (AgeSkyProfile.Body body : payload.sky().bodies()) {
+                            buffer.writeEnum(body.kind());
+                            buffer.writeInt(body.color());
+                            buffer.writeFloat(body.size());
+                            buffer.writeFloat(body.angle());
+                            buffer.writeDouble(body.period());
+                            buffer.writeFloat(body.phase());
+                            buffer.writeBoolean(body.clockwise());
+                        }
                     },
-                    buffer -> new AgeCelestialAnglePayload(
+                    buffer -> {
-                            buffer.readResourceKey(Registries.DIMENSION), buffer.readFloat())
+                        ResourceKey<Level> dimension = buffer.readResourceKey(Registries.DIMENSION);
+                        float angle = buffer.readFloat();
+                        AgeSkyProfile.Style style = buffer.readEnum(AgeSkyProfile.Style.class);
+                        int color = buffer.readInt();
+                        int count = buffer.readVarInt();
+                        if (count < 0 || count > 20) throw new IllegalArgumentException("Invalid celestial body count");
+                        java.util.List<AgeSkyProfile.Body> bodies = new java.util.ArrayList<>(count);
+                        for (int i = 0; i < count; i++) bodies.add(new AgeSkyProfile.Body(
+                                buffer.readEnum(AgeSkyProfile.Kind.class), buffer.readInt(),
+                                buffer.readFloat(), buffer.readFloat(), buffer.readDouble(), buffer.readFloat(),
+                                buffer.readBoolean()));
+                        return new AgeCelestialAnglePayload(dimension, angle,
+                                new AgeSkyProfile(style, color, bodies));
+                    }
             );
 
     @Override

src/main/java/net/dnorberg/rivencraft/network/ModNetworking.java

@@ -61,7 +61,7 @@ public final class ModNetworking {
     }
 
     public static void register(RegisterPayloadHandlersEvent event) {
-        PayloadRegistrar registrar = event.registrar("17");
+        PayloadRegistrar registrar = event.registrar("18");
         registrar.playToServer(RequestDescriptiveBookScreenPayload.TYPE, RequestDescriptiveBookScreenPayload.STREAM_CODEC,
                 ModNetworking::requestDescriptiveBookScreen);
         registrar.playToClient(OpenDescriptiveBookScreenPayload.TYPE, OpenDescriptiveBookScreenPayload.STREAM_CODEC,
@@ -81,6 +81,8 @@ public final class ModNetworking {
                 ClientLinkPreviewHandler::handle);
         registrar.playToClient(AgeCelestialAnglePayload.TYPE, AgeCelestialAnglePayload.STREAM_CODEC,
                 ClientAgeCelestialAngles::handle);
+        registrar.playToServer(RequestAgeSkyPayload.TYPE, RequestAgeSkyPayload.STREAM_CODEC,
+                ModNetworking::requestAgeSky);
         registrar.playToClient(SereneAgeWhitelistPayload.TYPE, SereneAgeWhitelistPayload.STREAM_CODEC,
                 ClientSereneAgeWhitelist::handle);
         registrar.playToClient(WritingDeskCatalogPayload.TYPE, WritingDeskCatalogPayload.STREAM_CODEC,
@@ -93,6 +95,16 @@ public final class ModNetworking {
                 ModNetworking::setLinkModifierSeed);
     }
 
+    private static void requestAgeSky(RequestAgeSkyPayload payload, IPayloadContext context) {
+        if (!(context.player() instanceof ServerPlayer player)) return;
+        // Portal renderers may request another Age. Only return registered Age data,
+        // never an arbitrary client-supplied dimension or generated terrain.
+        AgeRegistrySavedData.get(player.serverLevel()).definitions().stream()
+                .filter(age -> AgeDimensionService.dimensionKey(age).equals(payload.dimension()))
+                .findFirst()
+                .ifPresent(age -> AgeCelestialAngleSync.send(player, age));
+    }
+
     private static void setBookBinderTitle(SetBookBinderTitlePayload payload, IPayloadContext context) {
         if (context.player() instanceof ServerPlayer player
                 && player.containerMenu instanceof BookBinderMenu menu
@@ -348,8 +360,7 @@ public final class ModNetworking {
 
     /** Sky effects, not dimension IDs, decide the backdrop for custom Ages. */
     private static int previewSkyColor(ServerLevel level, BlockPos origin) {
-        return AgeEnvironmentCompiler.previewSkyColor(level.dimensionType().effectsLocation(),
+        return AgeEnvironmentCompiler.previewSkyColor(level, origin);
-                level.getBiome(origin).value().getSkyColor());
     }
 
     private static InteractionHand hand(boolean offhand) {

src/main/java/net/dnorberg/rivencraft/network/RequestAgeSkyPayload.java

@@ -0,0 +1,24 @@
+package net.dnorberg.rivencraft.network;
+
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.core.registries.Registries;
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.level.Level;
+
+/** Requests the saved sky profile when a renderer reaches an Age before dimension-change sync. */
+public record RequestAgeSkyPayload(ResourceKey<Level> dimension) implements CustomPacketPayload {
+    public static final Type<RequestAgeSkyPayload> TYPE = new Type<>(
+            ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "request_age_sky"));
+    public static final StreamCodec<RegistryFriendlyByteBuf, RequestAgeSkyPayload> STREAM_CODEC = StreamCodec.of(
+            (buffer, payload) -> buffer.writeResourceKey(payload.dimension()),
+            buffer -> new RequestAgeSkyPayload(buffer.readResourceKey(Registries.DIMENSION)));
+
+    @Override
+    public Type<? extends CustomPacketPayload> type() {
+        return TYPE;
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/SymbolSemantics.java

@@ -77,12 +77,18 @@ public record SymbolSemantics(Role role, Value value) {
                 "native", "single", "tiled", "grid", "tiny", "small", "medium", "large", "huge"),
         BIOME("biome", Kind.RESOURCE),
         LIGHTING("lighting", Kind.CHOICE, "normal", "dark", "bright"),
-        SKY("sky", Kind.CHOICE, "overworld", "nether", "end"),
+        SKY("sky", Kind.CHOICE, "overworld", "nether", "end", "static"),
+        SKY_COLOR("sky_color", Kind.CHOICE,
+                "red", "orange", "yellow", "green", "blue", "purple", "white", "black"),
         WEATHER("weather", Kind.CHOICE,
                 "normal", "fast", "slow", "off", "always", "cloudy", "rain", "snow", "storm"),
         SEASON("season", Kind.CHOICE,
                 "no_seasons", "seasons", "eternal_winter", "eternal_summer", "eternal_fall", "eternal_spring"),
-        CELESTIAL("celestial", Kind.CHOICE, "normal_time"),
+        CELESTIAL("celestial", Kind.CHOICE, "normal_time", "sun", "moon"),
+        CELESTIAL_COLOR("celestial_color", Kind.CHOICE,
+                "red", "orange", "yellow", "green", "blue", "purple", "white", "black"),
+        DIRECTION_MODIFIER("direction_modifier", Kind.CHOICE, "clockwise", "counterclockwise"),
+        SIZE_MODIFIER("size_modifier", Kind.NUMBER),
         PERIOD_MODIFIER("period_modifier", Kind.NUMBER),
         ANGLE_MODIFIER("angle_modifier", Kind.NUMBER),
         PHASE_MODIFIER("phase_modifier", Kind.NUMBER),
@@ -109,6 +115,7 @@ public record SymbolSemantics(Role role, Value value) {
             if (!(value instanceof NumberValue number)) return false;
             return switch (this) {
                 case PERIOD_MODIFIER -> number.amount() >= 0.0 && number.amount() <= 2.0;
+                case SIZE_MODIFIER -> number.amount() >= 0.25 && number.amount() <= 3.0;
                 case ANGLE_MODIFIER, PHASE_MODIFIER -> number.amount() >= 0.0 && number.amount() < 360.0;
                 default -> false;
             };
@@ -119,6 +126,7 @@ public record SymbolSemantics(Role role, Value value) {
                 case RESOURCE -> "a canonical namespaced ID";
                 case CHOICE -> "one of " + choices.stream().sorted().toList();
                 case NUMBER -> this == PERIOD_MODIFIER ? "a finite number in [0, 2]"
+                        : this == SIZE_MODIFIER ? "a finite number in [0.25, 3]"
                         : "a finite number in [0, 360) degrees";
             };
         }

src/main/java/net/dnorberg/rivencraft/writing/WritingGrammar.java

@@ -96,7 +96,7 @@ public final class WritingGrammar {
                 }
                 pendingBlock = null;
             }
-            if (role == Role.ANGLE_MODIFIER || role == Role.WEATHER
+            if (role == Role.WEATHER
                     && parsed.semantics().value() instanceof ChoiceValue choice
                     && UNSUPPORTED_WEATHER.contains(choice.id())) {
                 diagnostics.add(new Diagnostic(Code.UNSUPPORTED_ENVIRONMENT, index,
@@ -142,7 +142,10 @@ public final class WritingGrammar {
         }
         for (Role required : List.of(Role.TERRAIN, Role.BIOME_CONTROLLER, Role.WEATHER,
                 Role.LIGHTING, Role.CELESTIAL)) {
-            if (!singular.containsKey(required)) diagnostics.add(new Diagnostic(Code.INCOMPLETE, -1,
+            boolean present = required == Role.CELESTIAL
+                    ? symbols.stream().anyMatch(symbol -> symbol.semantics().role() == Role.CELESTIAL)
+                    : singular.containsKey(required);
+            if (!present) diagnostics.add(new Diagnostic(Code.INCOMPLETE, -1,
                     "The Age compiler will fill the missing " + required.id() + " branch from the Age seed"));
         }
         if (controller != null && controller.semantics().value() instanceof ChoiceValue choice) {
@@ -160,13 +163,15 @@ public final class WritingGrammar {
 
     private static boolean singular(Role role) {
         return switch (role) {
-            case TERRAIN, BIOME_CONTROLLER, WEATHER, SEASON, LIGHTING, SKY, CELESTIAL -> true;
+            case TERRAIN, BIOME_CONTROLLER, WEATHER, SEASON, LIGHTING, SKY -> true;
             default -> false;
         };
     }
 
     private static boolean modifier(Role role) {
-        return role == Role.PERIOD_MODIFIER || role == Role.ANGLE_MODIFIER || role == Role.PHASE_MODIFIER;
+        return role == Role.PERIOD_MODIFIER || role == Role.ANGLE_MODIFIER
+                || role == Role.PHASE_MODIFIER || role == Role.SIZE_MODIFIER
+                || role == Role.CELESTIAL_COLOR || role == Role.DIRECTION_MODIFIER;
     }
 
     private static int stage(Role role) {
@@ -177,8 +182,9 @@ public final class WritingGrammar {
             case WEATHER -> 3;
             case SEASON -> 4;
             case LIGHTING -> 5;
-            case SKY -> 6;
+            case SKY, SKY_COLOR -> 6;
-            case PERIOD_MODIFIER, ANGLE_MODIFIER, PHASE_MODIFIER -> 7;
+            case PERIOD_MODIFIER, ANGLE_MODIFIER, PHASE_MODIFIER, SIZE_MODIFIER,
+                    CELESTIAL_COLOR, DIRECTION_MODIFIER -> 7;
             case CELESTIAL -> 8;
             case BLOCK, FEATURE, ENVIRONMENT, CORRUPTED -> 9;
         };

src/main/resources/assets/rivencraft/lang/en_us.json

@@ -223,6 +223,24 @@
   "symbol.rivencraft.sky.nether.description": "Use the Nether sky and red preview background.",
   "symbol.rivencraft.sky.end": "End Sky",
   "symbol.rivencraft.sky.end.description": "Use the End sky and dark preview background.",
+  "symbol.rivencraft.sky.static": "Static Sky",
+  "symbol.rivencraft.sky.static.description": "Fill the sky with shifting television static.",
+  "symbol.rivencraft.sky_color.red": "Red Sky Color",
+  "symbol.rivencraft.sky_color.red.description": "Tint the sky and linked portal red.",
+  "symbol.rivencraft.sky_color.orange": "Orange Sky Color",
+  "symbol.rivencraft.sky_color.orange.description": "Tint the sky and linked portal orange.",
+  "symbol.rivencraft.sky_color.yellow": "Yellow Sky Color",
+  "symbol.rivencraft.sky_color.yellow.description": "Tint the sky and linked portal yellow.",
+  "symbol.rivencraft.sky_color.green": "Green Sky Color",
+  "symbol.rivencraft.sky_color.green.description": "Tint the sky and linked portal green.",
+  "symbol.rivencraft.sky_color.blue": "Blue Sky Color",
+  "symbol.rivencraft.sky_color.blue.description": "Tint the sky and linked portal blue.",
+  "symbol.rivencraft.sky_color.purple": "Purple Sky Color",
+  "symbol.rivencraft.sky_color.purple.description": "Tint the sky and linked portal purple.",
+  "symbol.rivencraft.sky_color.white": "White Sky Color",
+  "symbol.rivencraft.sky_color.white.description": "Tint the sky and linked portal white.",
+  "symbol.rivencraft.sky_color.black": "Black Sky Color",
+  "symbol.rivencraft.sky_color.black.description": "Tint the sky and linked portal near-black.",
   "symbol.rivencraft.weather.normal": "Normal Weather",
   "symbol.rivencraft.weather.normal.description": "Use the normal weather cycle.",
   "symbol.rivencraft.weather.fast": "Fast Weather",
@@ -249,6 +267,44 @@
   "symbol.rivencraft.season.eternal_spring.description": "Hold this Age in midspring.",
   "symbol.rivencraft.celestial.normal_time": "Normal Time",
   "symbol.rivencraft.celestial.normal_time.description": "Use a normal-length celestial cycle.",
+  "symbol.rivencraft.celestial.sun": "Sun",
+  "symbol.rivencraft.celestial.sun.description": "Add one independently moving sun to the sky.",
+  "symbol.rivencraft.celestial.moon": "Moon",
+  "symbol.rivencraft.celestial.moon.description": "Add one independently moving moon to the sky.",
+  "symbol.rivencraft.celestial_color.red": "Red Celestial",
+  "symbol.rivencraft.celestial_color.red.description": "Color the next sun or moon red.",
+  "symbol.rivencraft.celestial_color.orange": "Orange Celestial",
+  "symbol.rivencraft.celestial_color.orange.description": "Color the next sun or moon orange.",
+  "symbol.rivencraft.celestial_color.yellow": "Yellow Celestial",
+  "symbol.rivencraft.celestial_color.yellow.description": "Color the next sun or moon yellow.",
+  "symbol.rivencraft.celestial_color.green": "Green Celestial",
+  "symbol.rivencraft.celestial_color.green.description": "Color the next sun or moon green.",
+  "symbol.rivencraft.celestial_color.blue": "Blue Celestial",
+  "symbol.rivencraft.celestial_color.blue.description": "Color the next sun or moon blue.",
+  "symbol.rivencraft.celestial_color.purple": "Purple Celestial",
+  "symbol.rivencraft.celestial_color.purple.description": "Color the next sun or moon purple.",
+  "symbol.rivencraft.celestial_color.white": "White Celestial",
+  "symbol.rivencraft.celestial_color.white.description": "Color the next sun or moon white.",
+  "symbol.rivencraft.celestial_color.black": "Black Celestial",
+  "symbol.rivencraft.celestial_color.black.description": "Blend black into the next sun or moon's color.",
+  "symbol.rivencraft.size.small": "Small Celestial",
+  "symbol.rivencraft.size.small.description": "Halve the apparent size of the next sun or moon.",
+  "symbol.rivencraft.size.normal": "Normal Celestial Size",
+  "symbol.rivencraft.size.normal.description": "Set the next sun or moon to normal apparent size.",
+  "symbol.rivencraft.size.large": "Large Celestial",
+  "symbol.rivencraft.size.large.description": "Double the apparent size of the next sun or moon.",
+  "symbol.rivencraft.angle.north": "North Celestial Angle",
+  "symbol.rivencraft.angle.north.description": "Orient the next sun or moon toward the north.",
+  "symbol.rivencraft.angle.east": "East Celestial Angle",
+  "symbol.rivencraft.angle.east.description": "Orient the next sun or moon toward the east.",
+  "symbol.rivencraft.angle.south": "South Celestial Angle",
+  "symbol.rivencraft.angle.south.description": "Orient the next sun or moon toward the south.",
+  "symbol.rivencraft.angle.west": "West Celestial Angle",
+  "symbol.rivencraft.angle.west.description": "Orient the next sun or moon toward the west.",
+  "symbol.rivencraft.direction.clockwise": "Clockwise Motion",
+  "symbol.rivencraft.direction.clockwise.description": "Move the next sun or moon clockwise in its orbital plane.",
+  "symbol.rivencraft.direction.counterclockwise": "Counterclockwise Motion",
+  "symbol.rivencraft.direction.counterclockwise.description": "Move the next sun or moon counterclockwise in its orbital plane.",
   "symbol.rivencraft.period.zero": "Zero Length",
   "symbol.rivencraft.period.zero.description": "Stop the celestial cycle at its written phase.",
   "symbol.rivencraft.period.half": "Half Length",

src/main/resources/assets/rivencraft/models/block/crystal_portal.json

@@ -1 +1 @@
-{"render_type":"minecraft:translucent","ambientocclusion":false,"textures":{"particle":"rivencraft:block/crystal_portal","portal":"rivencraft:block/crystal_portal"},"elements":[{"from":[0,0,6],"to":[16,16,10],"shade":false,"faces":{"north":{"texture":"#portal"},"south":{"texture":"#portal"}}}]}
+{"render_type":"minecraft:translucent","ambientocclusion":false,"textures":{"particle":"rivencraft:block/crystal_portal","portal":"rivencraft:block/crystal_portal"},"elements":[{"from":[0,0,6],"to":[16,16,10],"shade":false,"faces":{"north":{"texture":"#portal","tintindex":0},"south":{"texture":"#portal","tintindex":0}}}]}

src/main/resources/data/rivencraft/rivencraft/symbols/angle/east.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.angle.east","description":"symbol.rivencraft.angle.east.description","category":"rivencraft:celestial","semantics":{"role":"angle_modifier","value":90.0},"poem":"Transform East Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/angle/north.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.angle.north","description":"symbol.rivencraft.angle.north.description","category":"rivencraft:celestial","semantics":{"role":"angle_modifier","value":0.0},"poem":"Transform North Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/angle/south.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.angle.south","description":"symbol.rivencraft.angle.south.description","category":"rivencraft:celestial","semantics":{"role":"angle_modifier","value":180.0},"poem":"Transform South Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/angle/west.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.angle.west","description":"symbol.rivencraft.angle.west.description","category":"rivencraft:celestial","semantics":{"role":"angle_modifier","value":270.0},"poem":"Transform West Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial/moon.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.celestial.moon","description":"symbol.rivencraft.celestial.moon.description","category":"rivencraft:celestial","semantics":{"role":"celestial","value":"moon"},"poem":"Transform Time Shadow Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial/sun.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.celestial.sun","description":"symbol.rivencraft.celestial.sun.description","category":"rivencraft:celestial","semantics":{"role":"celestial","value":"sun"},"poem":"Transform Time Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial_color/black.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.celestial_color.black","description":"symbol.rivencraft.celestial_color.black.description","category":"rivencraft:celestial","semantics":{"role":"celestial_color","value":"black"},"poem":"Transform Black Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial_color/blue.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.celestial_color.blue","description":"symbol.rivencraft.celestial_color.blue.description","category":"rivencraft:celestial","semantics":{"role":"celestial_color","value":"blue"},"poem":"Transform Blue Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial_color/green.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.celestial_color.green","description":"symbol.rivencraft.celestial_color.green.description","category":"rivencraft:celestial","semantics":{"role":"celestial_color","value":"green"},"poem":"Transform Green Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial_color/orange.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.celestial_color.orange","description":"symbol.rivencraft.celestial_color.orange.description","category":"rivencraft:celestial","semantics":{"role":"celestial_color","value":"orange"},"poem":"Transform Orange Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial_color/purple.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.celestial_color.purple","description":"symbol.rivencraft.celestial_color.purple.description","category":"rivencraft:celestial","semantics":{"role":"celestial_color","value":"purple"},"poem":"Transform Purple Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial_color/red.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.celestial_color.red","description":"symbol.rivencraft.celestial_color.red.description","category":"rivencraft:celestial","semantics":{"role":"celestial_color","value":"red"},"poem":"Transform Red Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial_color/white.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.celestial_color.white","description":"symbol.rivencraft.celestial_color.white.description","category":"rivencraft:celestial","semantics":{"role":"celestial_color","value":"white"},"poem":"Transform White Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial_color/yellow.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.celestial_color.yellow","description":"symbol.rivencraft.celestial_color.yellow.description","category":"rivencraft:celestial","semantics":{"role":"celestial_color","value":"yellow"},"poem":"Transform Yellow Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/direction/clockwise.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.direction.clockwise","description":"symbol.rivencraft.direction.clockwise.description","category":"rivencraft:celestial","semantics":{"role":"direction_modifier","value":"clockwise"},"poem":"Transform Time Clockwise Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/direction/counterclockwise.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.direction.counterclockwise","description":"symbol.rivencraft.direction.counterclockwise.description","category":"rivencraft:celestial","semantics":{"role":"direction_modifier","value":"counterclockwise"},"poem":"Transform Time Reverse Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/size/large.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.size.large","description":"symbol.rivencraft.size.large.description","category":"rivencraft:celestial","semantics":{"role":"size_modifier","value":2.0},"poem":"Transform Large Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/size/normal.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.size.normal","description":"symbol.rivencraft.size.normal.description","category":"rivencraft:celestial","semantics":{"role":"size_modifier","value":1.0},"poem":"Transform Balance Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/size/small.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.size.small","description":"symbol.rivencraft.size.small.description","category":"rivencraft:celestial","semantics":{"role":"size_modifier","value":0.5},"poem":"Transform Small Illuminate Motion"}

src/main/resources/data/rivencraft/rivencraft/symbols/sky/static.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.sky.static","description":"symbol.rivencraft.sky.static.description","category":"rivencraft:sky","semantics":{"role":"sky","value":"static"},"poem":"Ethereal Void Sky Flux"}

src/main/resources/data/rivencraft/rivencraft/symbols/sky_color/black.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.sky_color.black","description":"symbol.rivencraft.sky_color.black.description","category":"rivencraft:sky","semantics":{"role":"sky_color","value":"black"},"poem":"Ethereal Black Sky Balance"}

src/main/resources/data/rivencraft/rivencraft/symbols/sky_color/blue.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.sky_color.blue","description":"symbol.rivencraft.sky_color.blue.description","category":"rivencraft:sky","semantics":{"role":"sky_color","value":"blue"},"poem":"Ethereal Blue Sky Balance"}

src/main/resources/data/rivencraft/rivencraft/symbols/sky_color/green.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.sky_color.green","description":"symbol.rivencraft.sky_color.green.description","category":"rivencraft:sky","semantics":{"role":"sky_color","value":"green"},"poem":"Ethereal Green Sky Balance"}

src/main/resources/data/rivencraft/rivencraft/symbols/sky_color/orange.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.sky_color.orange","description":"symbol.rivencraft.sky_color.orange.description","category":"rivencraft:sky","semantics":{"role":"sky_color","value":"orange"},"poem":"Ethereal Orange Sky Balance"}

src/main/resources/data/rivencraft/rivencraft/symbols/sky_color/purple.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.sky_color.purple","description":"symbol.rivencraft.sky_color.purple.description","category":"rivencraft:sky","semantics":{"role":"sky_color","value":"purple"},"poem":"Ethereal Purple Sky Balance"}

src/main/resources/data/rivencraft/rivencraft/symbols/sky_color/red.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.sky_color.red","description":"symbol.rivencraft.sky_color.red.description","category":"rivencraft:sky","semantics":{"role":"sky_color","value":"red"},"poem":"Ethereal Red Sky Balance"}

src/main/resources/data/rivencraft/rivencraft/symbols/sky_color/white.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.sky_color.white","description":"symbol.rivencraft.sky_color.white.description","category":"rivencraft:sky","semantics":{"role":"sky_color","value":"white"},"poem":"Ethereal White Sky Balance"}

src/main/resources/data/rivencraft/rivencraft/symbols/sky_color/yellow.json

@@ -0,0 +1 @@
+{"schema_version":2,"name":"symbol.rivencraft.sky_color.yellow","description":"symbol.rivencraft.sky_color.yellow.description","category":"rivencraft:sky","semantics":{"role":"sky_color","value":"yellow"},"poem":"Ethereal Yellow Sky Balance"}

src/main/resources/rivencraft.mixins.json

@@ -5,12 +5,14 @@
   "compatibilityLevel": "JAVA_21",
   "mixins": [
     "AgeDimensionSeedMixin",
+    "LevelSkyBrightnessMixin",
     "AgeDungeonPlacementMixin",
     "AgeStructureBiomeMixin",
     "MobDropChanceAccessor",
     "StructurePlacementAccessor"
   ],
   "client": [
+    "client.ClientLevelSkyColorMixin",
     "client.ClientLevelSoundMixin",
     "client.ImmersivePortalsGuiRenderingMixin",
     "client.LevelRendererMixin"