Add mob drop viewer to item list

src/main/kotlin/moe/nea/firmament/gui/entity/EntityModifier.kt

@@ -0,0 +1,14 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.JsonObject
+import net.minecraft.entity.LivingEntity
+
+fun interface EntityModifier {
+    fun apply(entity: LivingEntity, info: JsonObject): LivingEntity
+}

src/main/kotlin/moe/nea/firmament/gui/entity/EntityRenderer.kt

@@ -0,0 +1,202 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.Gson
+import com.google.gson.JsonArray
+import com.google.gson.JsonObject
+import org.apache.logging.log4j.LogManager
+import org.joml.Quaternionf
+import org.joml.Vector3f
+import kotlin.math.atan
+import net.minecraft.client.gui.DrawContext
+import net.minecraft.client.gui.screen.ingame.InventoryScreen
+import net.minecraft.entity.Entity
+import net.minecraft.entity.EntityType
+import net.minecraft.entity.LivingEntity
+import net.minecraft.util.Identifier
+import moe.nea.firmament.util.MC
+import moe.nea.firmament.util.assertNotNullOr
+import moe.nea.firmament.util.iterate
+import moe.nea.firmament.util.openFirmamentResource
+import moe.nea.firmament.util.render.enableScissorWithTranslation
+
+object EntityRenderer {
+    val fakeWorld = FakeWorld()
+    private fun <T : Entity> t(entityType: EntityType<T>): () -> T {
+        return { entityType.create(fakeWorld)!! }
+    }
+
+    val entityIds: Map<String, () -> LivingEntity> = mapOf(
+        "Zombie" to t(EntityType.ZOMBIE),
+        "Chicken" to t(EntityType.CHICKEN),
+        "Slime" to t(EntityType.SLIME),
+        "Wolf" to t(EntityType.WOLF),
+        "Skeleton" to t(EntityType.SKELETON),
+        "Creeper" to t(EntityType.CREEPER),
+        "Ocelot" to t(EntityType.OCELOT),
+        "Blaze" to t(EntityType.BLAZE),
+        "Rabbit" to t(EntityType.RABBIT),
+        "Sheep" to t(EntityType.SHEEP),
+        "Horse" to t(EntityType.HORSE),
+        "Eisengolem" to t(EntityType.IRON_GOLEM),
+        "Silverfish" to t(EntityType.SILVERFISH),
+        "Witch" to t(EntityType.WITCH),
+        "Endermite" to t(EntityType.ENDERMITE),
+        "Snowman" to t(EntityType.SNOW_GOLEM),
+        "Villager" to t(EntityType.VILLAGER),
+        "Guardian" to t(EntityType.GUARDIAN),
+        "ArmorStand" to t(EntityType.ARMOR_STAND),
+        "Squid" to t(EntityType.SQUID),
+        "Bat" to t(EntityType.BAT),
+        "Spider" to t(EntityType.SPIDER),
+        "CaveSpider" to t(EntityType.CAVE_SPIDER),
+        "Pigman" to t(EntityType.ZOMBIFIED_PIGLIN),
+        "Ghast" to t(EntityType.GHAST),
+        "MagmaCube" to t(EntityType.MAGMA_CUBE),
+        "Wither" to t(EntityType.WITHER),
+        "Enderman" to t(EntityType.ENDERMAN),
+        "Mooshroom" to t(EntityType.MOOSHROOM),
+        "WitherSkeleton" to t(EntityType.WITHER_SKELETON),
+        "Cow" to t(EntityType.COW),
+        "Dragon" to t(EntityType.ENDER_DRAGON),
+        "Player" to { makeGuiPlayer(fakeWorld) },
+        "Pig" to t(EntityType.PIG),
+        "Giant" to t(EntityType.GIANT),
+    )
+    val entityModifiers: Map<String, EntityModifier> = mapOf(
+        "playerdata" to ModifyPlayerSkin,
+        "equipment" to ModifyEquipment,
+        "riding" to ModifyRiding,
+        "charged" to ModifyCharged,
+        "witherdata" to ModifyWither,
+        "invisible" to ModifyInvisible,
+        "age" to ModifyAge,
+        "horse" to ModifyHorse,
+        "name" to ModifyName,
+    )
+
+    val logger = LogManager.getLogger("Firmament.Entity")
+    fun applyModifiers(entityId: String, modifiers: List<JsonObject>): LivingEntity? {
+        val entityType = assertNotNullOr(entityIds[entityId]) {
+            logger.error("Could not create entity with id $entityId")
+            return null
+        }
+        var entity = entityType()
+        for (modifierJson in modifiers) {
+            val modifier = assertNotNullOr(modifierJson["type"]?.asString?.let(entityModifiers::get)) {
+                logger.error("Unknown modifier $modifierJson")
+                return null
+            }
+            entity = modifier.apply(entity, modifierJson)
+        }
+        return entity
+    }
+
+    fun constructEntity(info: JsonObject): LivingEntity? {
+        val modifiers = (info["modifiers"] as JsonArray?)?.map { it.asJsonObject } ?: emptyList()
+        val entityType = assertNotNullOr(info["entity"]?.asString) {
+            logger.error("Missing entity type on entity object")
+            return null
+        }
+        return applyModifiers(entityType, modifiers)
+    }
+
+    private val gson = Gson()
+    fun constructEntity(location: Identifier): LivingEntity? {
+        return constructEntity(
+            gson.fromJson(
+                location.openFirmamentResource().bufferedReader(), JsonObject::class.java
+            )
+        )
+    }
+
+    fun renderEntity(
+        entity: LivingEntity,
+        renderContext: DrawContext,
+        posX: Int,
+        posY: Int,
+        mouseX: Float,
+        mouseY: Float
+    ) {
+        var bottomOffset = 0.0F
+        var currentEntity = entity
+        val maxSize = entity.iterate { it.firstPassenger as? LivingEntity }
+            .map { it.height }
+            .sum()
+        while (true) {
+            currentEntity.age = MC.player?.age ?: 0
+            drawEntity(
+                renderContext,
+                posX,
+                posY,
+                posX + 50,
+                posY + 80,
+                (2F / maxSize * 30).toInt(),
+                -bottomOffset,
+                mouseX,
+                mouseY,
+                currentEntity
+            )
+            val next = currentEntity.firstPassenger as? LivingEntity ?: break
+            bottomOffset += currentEntity.getPassengerRidingPos(next).y.toFloat() * 0.75F
+            currentEntity = next
+        }
+    }
+
+
+    fun drawEntity(
+        context: DrawContext,
+        x1: Int,
+        y1: Int,
+        x2: Int,
+        y2: Int,
+        size: Int,
+        bottomOffset: Float,
+        mouseX: Float,
+        mouseY: Float,
+        entity: LivingEntity
+    ) {
+        context.enableScissorWithTranslation(x1.toFloat(), y1.toFloat(), x2.toFloat(), y2.toFloat())
+        val centerX = (x1 + x2) / 2f
+        val centerY = (y1 + y2) / 2f
+        val targetYaw = atan(((centerX - mouseX) / 40.0f).toDouble()).toFloat()
+        val targetPitch = atan(((centerY - mouseY) / 40.0f).toDouble()).toFloat()
+        val rotateToFaceTheFront = Quaternionf().rotateZ(Math.PI.toFloat())
+        val rotateToFaceTheCamera = Quaternionf().rotateX(targetPitch * 20.0f * (Math.PI.toFloat() / 180))
+        rotateToFaceTheFront.mul(rotateToFaceTheCamera)
+        val oldBodyYaw = entity.bodyYaw
+        val oldYaw = entity.yaw
+        val oldPitch = entity.pitch
+        val oldPrevHeadYaw = entity.prevHeadYaw
+        val oldHeadYaw = entity.headYaw
+        entity.bodyYaw = 180.0f + targetYaw * 20.0f
+        entity.yaw = 180.0f + targetYaw * 40.0f
+        entity.pitch = -targetPitch * 20.0f
+        entity.headYaw = entity.yaw
+        entity.prevHeadYaw = entity.yaw
+        val vector3f = Vector3f(0.0f, entity.height / 2.0f + bottomOffset, 0.0f)
+        InventoryScreen.drawEntity(
+            context,
+            centerX,
+            centerY,
+            size,
+            vector3f,
+            rotateToFaceTheFront,
+            rotateToFaceTheCamera,
+            entity
+        )
+        entity.bodyYaw = oldBodyYaw
+        entity.yaw = oldYaw
+        entity.pitch = oldPitch
+        entity.prevHeadYaw = oldPrevHeadYaw
+        entity.headYaw = oldHeadYaw
+        context.disableScissor()
+    }
+
+
+}

src/main/kotlin/moe/nea/firmament/gui/entity/EntityWidget.kt

@@ -0,0 +1,40 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import me.shedaniel.math.Dimension
+import me.shedaniel.math.Point
+import me.shedaniel.math.Rectangle
+import me.shedaniel.rei.api.client.gui.widgets.WidgetWithBounds
+import net.minecraft.client.gui.DrawContext
+import net.minecraft.client.gui.Element
+import net.minecraft.entity.LivingEntity
+
+class EntityWidget(val entity: LivingEntity, val point: Point) : WidgetWithBounds() {
+    override fun children(): List<Element> {
+        return emptyList()
+    }
+
+    var hasErrored = false
+
+    override fun render(context: DrawContext, mouseX: Int, mouseY: Int, delta: Float) {
+        try {
+            if (!hasErrored)
+                EntityRenderer.renderEntity(entity, context, point.x, point.y, mouseX.toFloat(), mouseY.toFloat())
+        } catch (ex: Exception) {
+            EntityRenderer.logger.error("Failed to render constructed entity: $entity", ex)
+            hasErrored = true
+        }
+        if (hasErrored) {
+            context.fill(point.x, point.y, point.x + 50, point.y + 80, 0xFFAA2222.toInt())
+        }
+    }
+
+    override fun getBounds(): Rectangle {
+        return Rectangle(point, Dimension(50, 80))
+    }
+}

src/main/kotlin/moe/nea/firmament/gui/entity/FakeWorld.kt

@@ -0,0 +1,491 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.mojang.datafixers.util.Pair
+import com.mojang.serialization.Lifecycle
+import java.util.*
+import java.util.function.BooleanSupplier
+import java.util.function.Consumer
+import java.util.stream.Stream
+import kotlin.jvm.optionals.getOrNull
+import kotlin.streams.asSequence
+import net.minecraft.block.Block
+import net.minecraft.block.BlockState
+import net.minecraft.client.world.ClientWorld
+import net.minecraft.entity.Entity
+import net.minecraft.entity.player.PlayerEntity
+import net.minecraft.fluid.Fluid
+import net.minecraft.item.map.MapState
+import net.minecraft.recipe.RecipeManager
+import net.minecraft.registry.BuiltinRegistries
+import net.minecraft.registry.DynamicRegistryManager
+import net.minecraft.registry.Registry
+import net.minecraft.registry.RegistryKey
+import net.minecraft.registry.RegistryKeys
+import net.minecraft.registry.RegistryWrapper
+import net.minecraft.registry.entry.RegistryEntry
+import net.minecraft.registry.entry.RegistryEntryList
+import net.minecraft.registry.entry.RegistryEntryOwner
+import net.minecraft.registry.tag.TagKey
+import net.minecraft.resource.featuretoggle.FeatureFlag
+import net.minecraft.resource.featuretoggle.FeatureFlags
+import net.minecraft.resource.featuretoggle.FeatureSet
+import net.minecraft.scoreboard.Scoreboard
+import net.minecraft.sound.SoundCategory
+import net.minecraft.sound.SoundEvent
+import net.minecraft.util.Identifier
+import net.minecraft.util.TypeFilter
+import net.minecraft.util.function.LazyIterationConsumer
+import net.minecraft.util.math.BlockPos
+import net.minecraft.util.math.Box
+import net.minecraft.util.math.ChunkPos
+import net.minecraft.util.math.Direction
+import net.minecraft.util.math.Vec3d
+import net.minecraft.util.math.random.Random
+import net.minecraft.util.profiler.DummyProfiler
+import net.minecraft.world.BlockView
+import net.minecraft.world.Difficulty
+import net.minecraft.world.GameRules
+import net.minecraft.world.MutableWorldProperties
+import net.minecraft.world.World
+import net.minecraft.world.biome.Biome
+import net.minecraft.world.biome.BiomeKeys
+import net.minecraft.world.chunk.Chunk
+import net.minecraft.world.chunk.ChunkManager
+import net.minecraft.world.chunk.ChunkStatus
+import net.minecraft.world.chunk.EmptyChunk
+import net.minecraft.world.chunk.light.LightingProvider
+import net.minecraft.world.entity.EntityLookup
+import net.minecraft.world.event.GameEvent
+import net.minecraft.world.tick.OrderedTick
+import net.minecraft.world.tick.QueryableTickScheduler
+import net.minecraft.world.tick.TickManager
+
+fun <T> makeRegistry(registryWrapper: RegistryWrapper.Impl<T>, key: RegistryKey<out Registry<T>>): Registry<T> {
+    val inverseLookup = registryWrapper.streamEntries()
+        .asSequence().map { it.value() to it.registryKey() }
+        .toMap()
+    val idLookup = registryWrapper.streamEntries()
+        .asSequence()
+        .map { it.registryKey() }
+        .withIndex()
+        .associate { it.value to it.index }
+    val map = registryWrapper.streamEntries().asSequence().map { it.registryKey() to it.value() }.toMap(mutableMapOf())
+    val inverseIdLookup = idLookup.asIterable().associate { (k, v) -> v to k }
+    return object : Registry<T> {
+        override fun get(key: RegistryKey<T>?): T? {
+            return registryWrapper.getOptional(key).getOrNull()?.value()
+        }
+
+        override fun iterator(): MutableIterator<T> {
+            return object : MutableIterator<T> {
+                val iterator = registryWrapper.streamEntries().iterator()
+                override fun hasNext(): Boolean {
+                    return iterator.hasNext()
+                }
+
+                override fun next(): T {
+                    return iterator.next().value()
+                }
+
+                override fun remove() {
+                    TODO("Not yet implemented")
+                }
+            }
+        }
+
+        override fun getRawId(value: T?): Int {
+            return idLookup[inverseLookup[value ?: return -1] ?: return -1] ?: return -1
+        }
+
+        override fun get(id: Identifier?): T? {
+            return get(RegistryKey.of(key, id))
+        }
+
+        override fun get(index: Int): T? {
+            return get(inverseIdLookup[index] ?: return null)
+        }
+
+        override fun size(): Int {
+            return idLookup.size
+        }
+
+        override fun getKey(): RegistryKey<out Registry<T>> {
+            return key
+        }
+
+        override fun getLifecycle(): Lifecycle {
+            return Lifecycle.stable()
+        }
+
+        override fun getIds(): MutableSet<Identifier> {
+            return idLookup.keys.mapTo(mutableSetOf()) { it.value }
+        }
+
+        override fun getEntrySet(): MutableSet<MutableMap.MutableEntry<RegistryKey<T>, T>> {
+            return map.entries
+        }
+
+        override fun getKeys(): MutableSet<RegistryKey<T>> {
+            return map.keys
+        }
+
+        override fun getRandom(random: Random?): Optional<RegistryEntry.Reference<T>> {
+            return registryWrapper.streamEntries().findFirst()
+        }
+
+        override fun containsId(id: Identifier?): Boolean {
+            return idLookup.containsKey(RegistryKey.of(key, id ?: return false))
+        }
+
+        override fun freeze(): Registry<T> {
+            return this
+        }
+
+        override fun getEntry(rawId: Int): Optional<RegistryEntry.Reference<T>> {
+            val x = inverseIdLookup[rawId] ?: return Optional.empty()
+            return Optional.of(RegistryEntry.Reference.standAlone(registryWrapper, x))
+        }
+
+        override fun streamEntries(): Stream<RegistryEntry.Reference<T>> {
+            return registryWrapper.streamEntries()
+        }
+
+        override fun streamTagsAndEntries(): Stream<Pair<TagKey<T>, RegistryEntryList.Named<T>>> {
+            return streamTags().map { Pair(it, getOrCreateEntryList(it)) }
+        }
+
+        override fun streamTags(): Stream<TagKey<T>> {
+            return registryWrapper.streamTagKeys()
+        }
+
+        override fun clearTags() {
+        }
+
+        override fun getEntryOwner(): RegistryEntryOwner<T> {
+            return registryWrapper
+        }
+
+        override fun getReadOnlyWrapper(): RegistryWrapper.Impl<T> {
+            return registryWrapper
+        }
+
+        override fun populateTags(tagEntries: MutableMap<TagKey<T>, MutableList<RegistryEntry<T>>>?) {
+        }
+
+        override fun getOrCreateEntryList(tag: TagKey<T>?): RegistryEntryList.Named<T> {
+            return getEntryList(tag).orElseGet { RegistryEntryList.of(registryWrapper, tag) }
+        }
+
+        override fun getEntryList(tag: TagKey<T>?): Optional<RegistryEntryList.Named<T>> {
+            return registryWrapper.getOptional(tag ?: return Optional.empty())
+        }
+
+        override fun getEntry(value: T): RegistryEntry<T> {
+            return registryWrapper.getOptional(inverseLookup[value]!!).get()
+        }
+
+        override fun getEntry(key: RegistryKey<T>?): Optional<RegistryEntry.Reference<T>> {
+            return registryWrapper.getOptional(key ?: return Optional.empty())
+        }
+
+        override fun createEntry(value: T): RegistryEntry.Reference<T> {
+            TODO()
+        }
+
+        override fun contains(key: RegistryKey<T>?): Boolean {
+            return getEntry(key).isPresent
+        }
+
+        override fun getEntryLifecycle(entry: T): Lifecycle {
+            return Lifecycle.stable()
+        }
+
+        override fun getId(value: T): Identifier? {
+            return (inverseLookup[value] ?: return null).value
+        }
+
+        override fun getKey(entry: T): Optional<RegistryKey<T>> {
+            return Optional.ofNullable(inverseLookup[entry ?: return Optional.empty()])
+        }
+    }
+}
+
+fun createDynamicRegistry(): DynamicRegistryManager.Immutable {
+    val wrapperLookup = BuiltinRegistries.createWrapperLookup()
+    return object : DynamicRegistryManager.Immutable {
+        override fun <E : Any?> getOptional(key: RegistryKey<out Registry<out E>>): Optional<Registry<E>> {
+            val lookup = wrapperLookup.getOptionalWrapper(key).getOrNull() ?: return Optional.empty()
+            val registry = makeRegistry(lookup, key as RegistryKey<out Registry<E>>)
+            return Optional.of(registry)
+        }
+
+        fun <T> entry(reg: RegistryKey<out Registry<T>>): DynamicRegistryManager.Entry<T> {
+            return DynamicRegistryManager.Entry(reg, getOptional(reg).get())
+        }
+
+        override fun streamAllRegistries(): Stream<DynamicRegistryManager.Entry<*>> {
+            return wrapperLookup.streamAllRegistryKeys()
+                .map { entry(it as RegistryKey<out Registry<Any>>) }
+        }
+    }
+}
+
+class FakeWorld(registries: DynamicRegistryManager.Immutable = createDynamicRegistry()) : World(
+    Properties,
+    RegistryKey.of(RegistryKeys.WORLD, Identifier.of("firmament", "fakeworld")),
+    registries,
+    registries[RegistryKeys.DIMENSION_TYPE].entryOf(
+        RegistryKey.of(
+            RegistryKeys.DIMENSION_TYPE,
+            Identifier("minecraft", "overworld")
+        )
+    ),
+    { DummyProfiler.INSTANCE },
+    true,
+    false,
+    0, 0
+) {
+    object Properties : MutableWorldProperties {
+        override fun getSpawnX(): Int {
+            return 0
+        }
+
+        override fun getSpawnY(): Int {
+            return 0
+        }
+
+        override fun getSpawnZ(): Int {
+            return 0
+        }
+
+        override fun getSpawnAngle(): Float {
+            return 0F
+        }
+
+        override fun getTime(): Long {
+            return 0
+        }
+
+        override fun getTimeOfDay(): Long {
+            return 0
+        }
+
+        override fun isThundering(): Boolean {
+            return false
+        }
+
+        override fun isRaining(): Boolean {
+            return false
+        }
+
+        override fun setRaining(raining: Boolean) {
+        }
+
+        override fun isHardcore(): Boolean {
+            return false
+        }
+
+        override fun getGameRules(): GameRules {
+            return GameRules()
+        }
+
+        override fun getDifficulty(): Difficulty {
+            return Difficulty.HARD
+        }
+
+        override fun isDifficultyLocked(): Boolean {
+            return false
+        }
+
+        override fun setSpawnX(spawnX: Int) {
+        }
+
+        override fun setSpawnY(spawnY: Int) {
+        }
+
+        override fun setSpawnZ(spawnZ: Int) {
+        }
+
+        override fun setSpawnAngle(spawnAngle: Float) {
+        }
+    }
+
+    override fun getPlayers(): List<PlayerEntity> {
+        return emptyList()
+    }
+
+    override fun getBrightness(direction: Direction?, shaded: Boolean): Float {
+        return 1f
+    }
+
+    override fun getGeneratorStoredBiome(biomeX: Int, biomeY: Int, biomeZ: Int): RegistryEntry<Biome> {
+        return registryManager.get(RegistryKeys.BIOME).entryOf(BiomeKeys.PLAINS)
+    }
+
+    override fun getEnabledFeatures(): FeatureSet {
+        return FeatureFlags.VANILLA_FEATURES
+    }
+
+    class FakeTickScheduler<T> : QueryableTickScheduler<T> {
+        override fun scheduleTick(orderedTick: OrderedTick<T>?) {
+        }
+
+        override fun isQueued(pos: BlockPos?, type: T): Boolean {
+            return true
+        }
+
+        override fun getTickCount(): Int {
+            return 0
+        }
+
+        override fun isTicking(pos: BlockPos?, type: T): Boolean {
+            return true
+        }
+
+    }
+
+    override fun getBlockTickScheduler(): QueryableTickScheduler<Block> {
+        return FakeTickScheduler()
+    }
+
+    override fun getFluidTickScheduler(): QueryableTickScheduler<Fluid> {
+        return FakeTickScheduler()
+    }
+
+
+    class FakeChunkManager(val world: FakeWorld) : ChunkManager() {
+        override fun getChunk(x: Int, z: Int, leastStatus: ChunkStatus?, create: Boolean): Chunk {
+            return EmptyChunk(world, ChunkPos(x,z), world.registryManager.get(RegistryKeys.BIOME).entryOf(BiomeKeys.PLAINS))
+        }
+
+        override fun getWorld(): BlockView {
+            return world
+        }
+
+        override fun tick(shouldKeepTicking: BooleanSupplier?, tickChunks: Boolean) {
+        }
+
+        override fun getDebugString(): String {
+            return "FakeChunkManager"
+        }
+
+        override fun getLoadedChunkCount(): Int {
+            return 0
+        }
+
+        override fun getLightingProvider(): LightingProvider {
+            return FakeLightingProvider(this)
+        }
+    }
+
+    class FakeLightingProvider(chunkManager: FakeChunkManager) : LightingProvider(chunkManager, false, false)
+
+    override fun getChunkManager(): ChunkManager {
+        return FakeChunkManager(this)
+    }
+
+    override fun playSound(
+        source: PlayerEntity?,
+        x: Double,
+        y: Double,
+        z: Double,
+        sound: RegistryEntry<SoundEvent>?,
+        category: SoundCategory?,
+        volume: Float,
+        pitch: Float,
+        seed: Long
+    ) {
+    }
+
+    override fun syncWorldEvent(player: PlayerEntity?, eventId: Int, pos: BlockPos?, data: Int) {
+    }
+
+    override fun emitGameEvent(event: GameEvent?, emitterPos: Vec3d?, emitter: GameEvent.Emitter?) {
+    }
+
+    override fun updateListeners(pos: BlockPos?, oldState: BlockState?, newState: BlockState?, flags: Int) {
+    }
+
+    override fun playSoundFromEntity(
+        source: PlayerEntity?,
+        entity: Entity?,
+        sound: RegistryEntry<SoundEvent>?,
+        category: SoundCategory?,
+        volume: Float,
+        pitch: Float,
+        seed: Long
+    ) {
+    }
+
+    override fun asString(): String {
+        return "FakeWorld"
+    }
+
+    override fun getEntityById(id: Int): Entity? {
+        return null
+    }
+
+    override fun getTickManager(): TickManager {
+        return TickManager()
+    }
+
+    override fun getMapState(id: String?): MapState? {
+        return null
+    }
+
+    override fun putMapState(id: String?, state: MapState?) {
+    }
+
+    override fun getNextMapId(): Int {
+        return 0
+    }
+
+    override fun setBlockBreakingInfo(entityId: Int, pos: BlockPos?, progress: Int) {
+    }
+
+    override fun getScoreboard(): Scoreboard {
+        return Scoreboard()
+    }
+
+    override fun getRecipeManager(): RecipeManager {
+        return RecipeManager()
+    }
+
+    object FakeEntityLookup : EntityLookup<Entity> {
+        override fun get(id: Int): Entity? {
+            return null
+        }
+
+        override fun get(uuid: UUID?): Entity? {
+            return null
+        }
+
+        override fun iterate(): MutableIterable<Entity> {
+            return mutableListOf()
+        }
+
+        override fun <U : Entity?> forEachIntersects(
+            filter: TypeFilter<Entity, U>?,
+            box: Box?,
+            consumer: LazyIterationConsumer<U>?
+        ) {
+        }
+
+        override fun forEachIntersects(box: Box?, action: Consumer<Entity>?) {
+        }
+
+        override fun <U : Entity?> forEach(filter: TypeFilter<Entity, U>?, consumer: LazyIterationConsumer<U>?) {
+        }
+
+    }
+
+    override fun getEntityLookup(): EntityLookup<Entity> {
+        return FakeEntityLookup
+    }
+}

src/main/kotlin/moe/nea/firmament/gui/entity/GuiPlayer.kt

@@ -0,0 +1,55 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.mojang.authlib.GameProfile
+import java.util.*
+import net.minecraft.client.network.AbstractClientPlayerEntity
+import net.minecraft.client.util.DefaultSkinHelper
+import net.minecraft.client.util.SkinTextures
+import net.minecraft.client.util.SkinTextures.Model
+import net.minecraft.client.world.ClientWorld
+import net.minecraft.util.Identifier
+import net.minecraft.util.math.BlockPos
+import net.minecraft.world.World
+
+/**
+ * @see moe.nea.firmament.init.EarlyRiser
+ */
+fun makeGuiPlayer(world: FakeWorld): GuiPlayer {
+    val constructor = GuiPlayer::class.java.getDeclaredConstructor(
+        World::class.java,
+        BlockPos::class.java,
+        Float::class.javaPrimitiveType,
+        GameProfile::class.java
+    )
+    return constructor.newInstance(world, BlockPos.ORIGIN, 0F, GameProfile(UUID.randomUUID(), "Linnea"))
+}
+
+class GuiPlayer(world: ClientWorld?, profile: GameProfile?) : AbstractClientPlayerEntity(world, profile) {
+    override fun isSpectator(): Boolean {
+        return false
+    }
+
+    override fun isCreative(): Boolean {
+        return false
+    }
+
+    var skinTexture: Identifier = DefaultSkinHelper.getSkinTextures(this.getUuid()).texture
+    var capeTexture: Identifier? = null
+    var model: Model = Model.WIDE
+    override fun getSkinTextures(): SkinTextures {
+        return SkinTextures(
+            skinTexture,
+            null,
+            capeTexture,
+            null,
+            model,
+            true
+        )
+    }
+}

src/main/kotlin/moe/nea/firmament/gui/entity/ModifyAge.kt

@@ -0,0 +1,30 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.JsonObject
+import net.minecraft.entity.LivingEntity
+import net.minecraft.entity.decoration.ArmorStandEntity
+import net.minecraft.entity.mob.ZombieEntity
+import net.minecraft.entity.passive.PassiveEntity
+
+object ModifyAge : EntityModifier {
+    override fun apply(entity: LivingEntity, info: JsonObject): LivingEntity {
+        val isBaby = info["baby"]?.asBoolean ?: false
+        if (entity is PassiveEntity) {
+            entity.breedingAge = if (isBaby) -1 else 1
+        } else if (entity is ZombieEntity) {
+            entity.isBaby = isBaby
+        } else if (entity is ArmorStandEntity) {
+            entity.isSmall = isBaby
+        } else {
+            error("Cannot set age for $entity")
+        }
+        return entity
+    }
+
+}

src/main/kotlin/moe/nea/firmament/gui/entity/ModifyCharged.kt

@@ -0,0 +1,19 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.JsonObject
+import net.minecraft.entity.LivingEntity
+import net.minecraft.entity.mob.CreeperEntity
+
+object ModifyCharged : EntityModifier {
+    override fun apply(entity: LivingEntity, info: JsonObject): LivingEntity {
+        require(entity is CreeperEntity)
+        entity.dataTracker.set(CreeperEntity.CHARGED, true)
+        return entity
+    }
+}

src/main/kotlin/moe/nea/firmament/gui/entity/ModifyEquipment.kt

@@ -0,0 +1,59 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.JsonObject
+import net.minecraft.entity.EquipmentSlot
+import net.minecraft.entity.LivingEntity
+import net.minecraft.item.DyeableArmorItem
+import net.minecraft.item.Item
+import net.minecraft.item.ItemStack
+import net.minecraft.item.Items
+import moe.nea.firmament.rei.SBItemStack
+import moe.nea.firmament.util.SkyblockId
+import moe.nea.firmament.util.item.setEncodedSkullOwner
+import moe.nea.firmament.util.item.zeroUUID
+
+object ModifyEquipment : EntityModifier {
+    val names = mapOf(
+        "hand" to EquipmentSlot.MAINHAND,
+        "helmet" to EquipmentSlot.HEAD,
+        "chestplate" to EquipmentSlot.CHEST,
+        "leggings" to EquipmentSlot.LEGS,
+        "feet" to EquipmentSlot.FEET,
+    )
+
+    override fun apply(entity: LivingEntity, info: JsonObject): LivingEntity {
+        names.forEach { (key, slot) ->
+            info[key]?.let {
+                entity.equipStack(slot, createItem(it.asString))
+            }
+        }
+        return entity
+    }
+
+    private fun createItem(item: String): ItemStack {
+        val split = item.split("#")
+        if (split.size != 2) return SBItemStack(SkyblockId(item)).asImmutableItemStack()
+        val (type, data) = split
+        return when (type) {
+            "SKULL" -> ItemStack(Items.PLAYER_HEAD).also { it.setEncodedSkullOwner(zeroUUID, data) }
+            "LEATHER_LEGGINGS" -> coloredLeatherArmor(Items.LEATHER_LEGGINGS, data)
+            "LEATHER_BOOTS" -> coloredLeatherArmor(Items.LEATHER_BOOTS, data)
+            "LEATHER_HELMET" -> coloredLeatherArmor(Items.LEATHER_HELMET, data)
+            "LEATHER_CHESTPLATE" -> coloredLeatherArmor(Items.LEATHER_CHESTPLATE, data)
+            else -> error("Unknown leather piece: $type")
+        }
+    }
+
+    private fun coloredLeatherArmor(leatherArmor: Item, data: String): ItemStack {
+        require(leatherArmor is DyeableArmorItem)
+        val stack = ItemStack(leatherArmor)
+        leatherArmor.setColor(stack, data.toInt(16))
+        return stack
+    }
+}

src/main/kotlin/moe/nea/firmament/gui/entity/ModifyHorse.kt

@@ -0,0 +1,66 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.JsonNull
+import com.google.gson.JsonObject
+import kotlin.experimental.and
+import kotlin.experimental.inv
+import kotlin.experimental.or
+import net.minecraft.entity.EntityType
+import net.minecraft.entity.LivingEntity
+import net.minecraft.entity.passive.AbstractHorseEntity
+import net.minecraft.item.ItemStack
+import net.minecraft.item.Items
+import moe.nea.firmament.gui.entity.EntityRenderer.fakeWorld
+
+object ModifyHorse : EntityModifier {
+    override fun apply(entity: LivingEntity, info: JsonObject): LivingEntity {
+        require(entity is AbstractHorseEntity)
+        var entity: AbstractHorseEntity = entity
+        info["kind"]?.let {
+            entity = when (it.asString) {
+                "skeleton" -> EntityType.SKELETON_HORSE.create(fakeWorld)!!
+                "zombie" -> EntityType.ZOMBIE_HORSE.create(fakeWorld)!!
+                "mule" -> EntityType.MULE.create(fakeWorld)!!
+                "donkey" -> EntityType.DONKEY.create(fakeWorld)!!
+                "horse" -> EntityType.HORSE.create(fakeWorld)!!
+                else -> error("Unknown horse kind $it")
+            }
+        }
+        info["armor"]?.let {
+            if (it is JsonNull) {
+                entity.setHorseArmor(ItemStack.EMPTY)
+            } else {
+                when (it.asString) {
+                    "iron" -> entity.setHorseArmor(ItemStack(Items.IRON_HORSE_ARMOR))
+                    "golden" -> entity.setHorseArmor(ItemStack(Items.GOLDEN_HORSE_ARMOR))
+                    "diamond" -> entity.setHorseArmor(ItemStack(Items.DIAMOND_HORSE_ARMOR))
+                    else -> error("Unknown horse armor $it")
+                }
+            }
+        }
+        info["saddled"]?.let {
+            entity.setIsSaddled(it.asBoolean)
+        }
+        return entity
+    }
+
+}
+
+fun AbstractHorseEntity.setIsSaddled(shouldBeSaddled: Boolean) {
+    val oldFlag = dataTracker.get(AbstractHorseEntity.HORSE_FLAGS)
+    dataTracker.set(
+        AbstractHorseEntity.HORSE_FLAGS,
+        if (shouldBeSaddled) oldFlag or AbstractHorseEntity.SADDLED_FLAG.toByte()
+        else oldFlag and AbstractHorseEntity.SADDLED_FLAG.toByte().inv()
+    )
+}
+
+fun AbstractHorseEntity.setHorseArmor(itemStack: ItemStack) {
+    items.setStack(1, itemStack)
+}

src/main/kotlin/moe/nea/firmament/gui/entity/ModifyInvisible.kt

@@ -0,0 +1,18 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.JsonObject
+import net.minecraft.entity.LivingEntity
+
+object ModifyInvisible : EntityModifier {
+    override fun apply(entity: LivingEntity, info: JsonObject): LivingEntity {
+        entity.isInvisible = info.get("invisible")?.asBoolean ?: true
+        return entity
+    }
+
+}

src/main/kotlin/moe/nea/firmament/gui/entity/ModifyName.kt

@@ -0,0 +1,19 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.JsonObject
+import net.minecraft.entity.LivingEntity
+import net.minecraft.text.Text
+
+object ModifyName : EntityModifier {
+    override fun apply(entity: LivingEntity, info: JsonObject): LivingEntity {
+        entity.customName = Text.literal(info.get("name").asString)
+        return entity
+    }
+
+}

src/main/kotlin/moe/nea/firmament/gui/entity/ModifyPlayerSkin.kt

@@ -0,0 +1,32 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.JsonObject
+import net.minecraft.client.util.SkinTextures
+import net.minecraft.entity.LivingEntity
+import net.minecraft.util.Identifier
+
+object ModifyPlayerSkin : EntityModifier {
+    override fun apply(entity: LivingEntity, info: JsonObject): LivingEntity {
+        require(entity is GuiPlayer)
+        info["cape"]?.let {
+            entity.capeTexture = Identifier(it.asString)
+        }
+        info["skin"]?.let {
+            entity.skinTexture = Identifier(it.asString)
+        }
+        info["slim"]?.let {
+            entity.model = if (it.asBoolean) SkinTextures.Model.SLIM else SkinTextures.Model.WIDE
+        }
+        info["parts"]?.let {
+            // TODO: support parts
+        }
+        return entity
+    }
+
+}

src/main/kotlin/moe/nea/firmament/gui/entity/ModifyRiding.kt

@@ -0,0 +1,20 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.JsonObject
+import net.minecraft.entity.LivingEntity
+
+object ModifyRiding : EntityModifier {
+    override fun apply(entity: LivingEntity, info: JsonObject): LivingEntity {
+        val newEntity = EntityRenderer.constructEntity(info)
+        require(newEntity != null)
+        newEntity.startRiding(entity, true)
+        return entity
+    }
+
+}

src/main/kotlin/moe/nea/firmament/gui/entity/ModifyWither.kt

@@ -0,0 +1,25 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.gui.entity
+
+import com.google.gson.JsonObject
+import net.minecraft.entity.LivingEntity
+import net.minecraft.entity.boss.WitherEntity
+
+object ModifyWither : EntityModifier {
+    override fun apply(entity: LivingEntity, info: JsonObject): LivingEntity {
+        require(entity is WitherEntity)
+        info["tiny"]?.let {
+            entity.setInvulTimer(if (it.asBoolean) 800 else 0)
+        }
+        info["armored"]?.let {
+            entity.health = if (it.asBoolean) 1F else entity.maxHealth
+        }
+        return entity
+    }
+
+}