feat: register and activate player cosmetics

.gitignore

@@ -2,4 +2,9 @@
 .idea
 build
 gradle
+!gradle/
+gradle/*
+!gradle/wrapper/
+gradle/wrapper/*
+!gradle/wrapper/gradle-wrapper.jar
 run

build.gradle

@@ -12,6 +12,7 @@ base {
 
 repositories {
     mavenCentral()
+    maven { url 'https://dl.cloudsmith.io/public/geckolib3/geckolib/maven/' }
     maven { url 'https://maven.wispforest.io/releases/' }
     maven { url 'https://jitpack.io' }
 }
@@ -22,6 +23,7 @@ dependencies {
 
     implementation "net.fabricmc:fabric-loader:0.18.4"
     implementation "net.fabricmc.fabric-api:fabric-api:0.154.0+26.1.2"
+    implementation "com.geckolib:geckolib-fabric-26.1.2:5.5.1"
 
     implementation "io.wispforest:owo-lib:0.13.0+26.1"
     include "io.wispforest:owo-sentinel:0.13.0+26.1"

gradle/wrapper/gradle-wrapper.properties

@@ -1 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
 distributionUrl=https\://services.gradle.org/distributions/gradle-9.4.1-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,248 @@
+#!/bin/sh
+
+#
+# Copyright © 2015 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/2d6327017519d23b96af35865dc997fcb544fb40/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,93 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

src/main/java/de/fullrisk/citrusDev/client/CitrusDevClient.java

@@ -4,14 +4,19 @@ package de.fullrisk.citrusDev.client;
 import de.fullrisk.citrusDev.Config;
 import de.fullrisk.citrusDev.UI.*;
 import de.fullrisk.citrusDev.UIHelper.DraggableHud;
+import de.fullrisk.citrusDev.client.cosmetic.PlayerCosmeticManager;
+import de.fullrisk.citrusDev.client.cosmetic.PlayerCosmeticRenderLayer;
 import de.fullrisk.citrusDev.helper.RankHelper;
 import net.fabricmc.api.ClientModInitializer;
 import net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientLifecycleEvents;
 import net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientTickEvents;
 import net.fabricmc.fabric.api.client.keymapping.v1.KeyMappingHelper;
 import net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents;
+import net.fabricmc.fabric.api.client.rendering.v1.LivingEntityRenderLayerRegistrationCallback;
 import net.minecraft.client.KeyMapping;
+import net.minecraft.client.renderer.entity.player.AvatarRenderer;
 import net.minecraft.resources.Identifier;
+import net.minecraft.world.entity.EntityType;
 import org.lwjgl.glfw.GLFW;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -25,9 +30,11 @@ public class CitrusDevClient implements ClientModInitializer {
     public static final String API_URL = "https://citrus-api.winniepat.de";
 
     private static KeyMapping openScreenKey;
+    private static boolean testCosmeticPending;
 
     @Override
     public void onInitializeClient() {
+        registerPlayerCosmetics();
         Module_FPS.register();
         Module_KeyStrokes.register();
         Module_Coords.register();
@@ -36,7 +43,11 @@ public class CitrusDevClient implements ClientModInitializer {
 
         ClientLifecycleEvents.CLIENT_STOPPING.register(client -> DiscordRPCManager.shutdown());
 
-        ClientPlayConnectionEvents.DISCONNECT.register((handler, client) -> DiscordRPCManager.setIdle());
+        ClientPlayConnectionEvents.DISCONNECT.register((handler, client) -> {
+            DiscordRPCManager.setIdle();
+            PlayerCosmeticManager.clear();
+            testCosmeticPending = false;
+        });
 
         KeyMapping.Category category = KeyMapping.Category.register(
                 Identifier.fromNamespaceAndPath("citrus-dev", "general"));
@@ -47,12 +58,23 @@ public class CitrusDevClient implements ClientModInitializer {
                 category
         ));
 
-        ClientPlayConnectionEvents.JOIN.register((sender, client1, player) -> {
+        ClientPlayConnectionEvents.JOIN.register((handler, sender, client) -> {
             RankHelper.fetchAllRanks();
+
+            if (client.player != null) {
+                PlayerCosmeticManager.enableTestCosmetic(client.player.getUUID());
+            } else {
+                testCosmeticPending = true;
+            }
         });
 
         ClientTickEvents.END_CLIENT_TICK.register(client -> {
 
+            if (testCosmeticPending && client.player != null) {
+                PlayerCosmeticManager.enableTestCosmetic(client.player.getUUID());
+                testCosmeticPending = false;
+            }
+
             if (client.player != null && !client.isPaused()) {
                 PlaytimeTracker.tick();
                 QuestsPanel.tick();
@@ -80,6 +102,17 @@ public class CitrusDevClient implements ClientModInitializer {
         });
     }
 
+    private static void registerPlayerCosmetics() {
+        LivingEntityRenderLayerRegistrationCallback.EVENT.register(
+                (entityType, entityRenderer, registrationHelper, context) -> {
+                    if (entityType == EntityType.PLAYER
+                            && entityRenderer instanceof AvatarRenderer<?> avatarRenderer) {
+                        registrationHelper.register(new PlayerCosmeticRenderLayer(avatarRenderer));
+                    }
+                }
+        );
+    }
+
     public static void debugLog(String message) {
         if (debug) {
             logger.info("[Citrus] [DEBUG] {}", message);

src/main/java/de/fullrisk/citrusDev/client/cosmetic/CosmeticData.java

@@ -0,0 +1,6 @@
+package de.fullrisk.citrusDev.client.cosmetic;
+
+import net.minecraft.resources.Identifier;
+
+public record CosmeticData(Identifier id, boolean visible) {
+}

src/main/java/de/fullrisk/citrusDev/client/cosmetic/CosmeticRenderData.java

@@ -0,0 +1,6 @@
+package de.fullrisk.citrusDev.client.cosmetic;
+
+import java.util.UUID;
+
+public record CosmeticRenderData(UUID playerId, CosmeticData cosmetic, float partialTick) {
+}

src/main/java/de/fullrisk/citrusDev/client/cosmetic/CosmeticRenderStateKeys.java

@@ -0,0 +1,14 @@
+package de.fullrisk.citrusDev.client.cosmetic;
+
+import net.fabricmc.fabric.api.client.rendering.v1.RenderStateDataKey;
+import net.minecraft.client.renderer.state.level.CameraRenderState;
+
+public final class CosmeticRenderStateKeys {
+    public static final RenderStateDataKey<CosmeticRenderData> COSMETIC =
+            RenderStateDataKey.create(() -> "citrus-dev player cosmetic");
+    public static final RenderStateDataKey<CameraRenderState> CAMERA =
+            RenderStateDataKey.create(() -> "citrus-dev camera render state");
+
+    private CosmeticRenderStateKeys() {
+    }
+}

src/main/java/de/fullrisk/citrusDev/client/cosmetic/PlayerCosmetic.java

@@ -0,0 +1,24 @@
+package de.fullrisk.citrusDev.client.cosmetic;
+
+import com.geckolib.animatable.GeoAnimatable;
+import com.geckolib.animatable.instance.AnimatableInstanceCache;
+import com.geckolib.animatable.manager.AnimatableManager;
+import com.geckolib.animation.AnimationController;
+import com.geckolib.animation.RawAnimation;
+import com.geckolib.util.GeckoLibUtil;
+
+public final class PlayerCosmetic implements GeoAnimatable {
+    private static final RawAnimation IDLE = RawAnimation.begin().thenLoop("animation.backpack.idle");
+
+    private final AnimatableInstanceCache cache = GeckoLibUtil.createInstanceCache(this, false);
+
+    @Override
+    public void registerControllers(AnimatableManager.ControllerRegistrar controllers) {
+        controllers.add(new AnimationController<PlayerCosmetic>(state -> state.setAndContinue(IDLE)));
+    }
+
+    @Override
+    public AnimatableInstanceCache getAnimatableInstanceCache() {
+        return cache;
+    }
+}

src/main/java/de/fullrisk/citrusDev/client/cosmetic/PlayerCosmeticManager.java

@@ -0,0 +1,43 @@
+package de.fullrisk.citrusDev.client.cosmetic;
+
+import net.minecraft.resources.Identifier;
+
+import java.util.Optional;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+
+public final class PlayerCosmeticManager {
+    private static final ConcurrentHashMap<UUID, CosmeticData> COSMETICS = new ConcurrentHashMap<>();
+    private static final ConcurrentHashMap<UUID, PlayerCosmetic> ANIMATABLES = new ConcurrentHashMap<>();
+    private static final CosmeticData TEST_BACKPACK = new CosmeticData(
+            Identifier.fromNamespaceAndPath("citrus-dev", "backpack"), true);
+
+    private PlayerCosmeticManager() {
+    }
+
+    public static Optional<CosmeticData> getCosmetic(UUID playerId) {
+        return Optional.ofNullable(COSMETICS.get(playerId));
+    }
+
+    public static void setCosmetic(UUID playerId, CosmeticData cosmetic) {
+        COSMETICS.put(playerId, cosmetic);
+    }
+
+    public static void removeCosmetic(UUID playerId) {
+        COSMETICS.remove(playerId);
+        ANIMATABLES.remove(playerId);
+    }
+
+    public static PlayerCosmetic getOrCreateAnimatable(UUID playerId) {
+        return ANIMATABLES.computeIfAbsent(playerId, ignored -> new PlayerCosmetic());
+    }
+
+    public static void clear() {
+        COSMETICS.clear();
+        ANIMATABLES.clear();
+    }
+
+    public static void enableTestCosmetic(UUID playerId) {
+        setCosmetic(playerId, TEST_BACKPACK);
+    }
+}

src/main/java/de/fullrisk/citrusDev/client/cosmetic/PlayerCosmeticModel.java

@@ -0,0 +1,29 @@
+package de.fullrisk.citrusDev.client.cosmetic;
+
+import com.geckolib.model.GeoModel;
+import com.geckolib.renderer.base.GeoRenderState;
+import net.minecraft.resources.Identifier;
+
+public final class PlayerCosmeticModel extends GeoModel<PlayerCosmetic> {
+    private static final Identifier MODEL = Identifier.fromNamespaceAndPath(
+            "citrus-dev", "geckolib/models/player/backpack.geo.json");
+    private static final Identifier TEXTURE = Identifier.fromNamespaceAndPath(
+            "citrus-dev", "textures/cosmetic/backpack.png");
+    private static final Identifier ANIMATION = Identifier.fromNamespaceAndPath(
+            "citrus-dev", "geckolib/animations/backpack.animation.json");
+
+    @Override
+    public Identifier getModelResource(GeoRenderState renderState) {
+        return MODEL;
+    }
+
+    @Override
+    public Identifier getTextureResource(GeoRenderState renderState) {
+        return TEXTURE;
+    }
+
+    @Override
+    public Identifier getAnimationResource(PlayerCosmetic animatable) {
+        return ANIMATION;
+    }
+}

src/main/java/de/fullrisk/citrusDev/client/cosmetic/PlayerCosmeticRenderLayer.java

@@ -0,0 +1,57 @@
+package de.fullrisk.citrusDev.client.cosmetic;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+import net.minecraft.client.model.player.PlayerModel;
+import net.minecraft.client.renderer.SubmitNodeCollector;
+import net.minecraft.client.renderer.entity.RenderLayerParent;
+import net.minecraft.client.renderer.entity.layers.RenderLayer;
+import net.minecraft.client.renderer.entity.state.AvatarRenderState;
+import net.minecraft.client.renderer.state.level.CameraRenderState;
+
+public final class PlayerCosmeticRenderLayer extends RenderLayer<AvatarRenderState, PlayerModel> {
+    // Blockbench uses Minecraft model units around the vanilla body origin; no corrective transform is needed.
+    private static final float MODEL_SCALE = 1.0F;
+
+    private final PlayerCosmeticRenderer renderer = new PlayerCosmeticRenderer();
+
+    public PlayerCosmeticRenderLayer(RenderLayerParent<AvatarRenderState, PlayerModel> parent) {
+        super(parent);
+    }
+
+    @Override
+    public void submit(
+            PoseStack poseStack,
+            SubmitNodeCollector nodeCollector,
+            int packedLight,
+            AvatarRenderState state,
+            float limbAngle,
+            float limbDistance
+    ) {
+        CosmeticRenderData renderData = state.getData(CosmeticRenderStateKeys.COSMETIC);
+        CameraRenderState cameraRenderState = state.getData(CosmeticRenderStateKeys.CAMERA);
+
+        if (renderData == null || cameraRenderState == null || state.isInvisible || state.isSpectator
+                || !renderData.cosmetic().visible()) {
+            return;
+        }
+
+        PlayerCosmetic animatable = PlayerCosmeticManager.getOrCreateAnimatable(renderData.playerId());
+        poseStack.pushPose();
+
+        try {
+            getParentModel().body.translateAndRotate(poseStack);
+            poseStack.scale(MODEL_SCALE, MODEL_SCALE, MODEL_SCALE);
+            renderer.performRenderPass(
+                    animatable,
+                    renderData,
+                    poseStack,
+                    nodeCollector,
+                    cameraRenderState,
+                    packedLight,
+                    renderData.partialTick()
+            );
+        } finally {
+            poseStack.popPose();
+        }
+    }
+}

src/main/java/de/fullrisk/citrusDev/client/cosmetic/PlayerCosmeticRenderer.java

@@ -0,0 +1,26 @@
+package de.fullrisk.citrusDev.client.cosmetic;
+
+import com.geckolib.renderer.GeoObjectRenderer;
+import com.geckolib.renderer.base.GeoRenderState;
+import com.geckolib.renderer.base.RenderPassInfo;
+
+import java.util.UUID;
+
+public final class PlayerCosmeticRenderer extends GeoObjectRenderer<
+        PlayerCosmetic, CosmeticRenderData, GeoRenderState> {
+
+    public PlayerCosmeticRenderer() {
+        super(new PlayerCosmeticModel());
+    }
+
+    @Override
+    public long getInstanceId(PlayerCosmetic animatable, CosmeticRenderData data) {
+        UUID uuid = data.playerId();
+        return uuid.getMostSignificantBits() ^ uuid.getLeastSignificantBits();
+    }
+
+    @Override
+    public void adjustRenderPose(RenderPassInfo<GeoRenderState> renderPassInfo) {
+        // The layer already supplies a body-local pose; omit GeoObjectRenderer's block-centering offset.
+    }
+}

src/main/java/de/fullrisk/citrusDev/mixin/AvatarRendererMixin.java

@@ -0,0 +1,38 @@
+package de.fullrisk.citrusDev.mixin;
+
+import de.fullrisk.citrusDev.client.cosmetic.CosmeticData;
+import de.fullrisk.citrusDev.client.cosmetic.CosmeticRenderData;
+import de.fullrisk.citrusDev.client.cosmetic.CosmeticRenderStateKeys;
+import de.fullrisk.citrusDev.client.cosmetic.PlayerCosmeticManager;
+import net.minecraft.client.renderer.entity.player.AvatarRenderer;
+import net.minecraft.client.renderer.entity.state.AvatarRenderState;
+import net.minecraft.world.entity.Avatar;
+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.CallbackInfo;
+
+import java.util.UUID;
+
+@Mixin(AvatarRenderer.class)
+abstract class AvatarRendererMixin {
+    @Inject(
+            method = "extractRenderState(Lnet/minecraft/world/entity/Avatar;Lnet/minecraft/client/renderer/entity/state/AvatarRenderState;F)V",
+            at = @At("TAIL")
+    )
+    private void citrus$extractCosmetic(
+            Avatar avatar,
+            AvatarRenderState state,
+            float partialTick,
+            CallbackInfo callbackInfo
+    ) {
+        UUID playerId = avatar.getUUID();
+        CosmeticData cosmetic = PlayerCosmeticManager.getCosmetic(playerId)
+                .filter(CosmeticData::visible)
+                .orElse(null);
+        state.setData(
+                CosmeticRenderStateKeys.COSMETIC,
+                cosmetic == null ? null : new CosmeticRenderData(playerId, cosmetic, partialTick)
+        );
+    }
+}

src/main/java/de/fullrisk/citrusDev/mixin/LivingEntityRendererMixin.java

@@ -0,0 +1,32 @@
+package de.fullrisk.citrusDev.mixin;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+import de.fullrisk.citrusDev.client.cosmetic.CosmeticRenderStateKeys;
+import net.minecraft.client.renderer.SubmitNodeCollector;
+import net.minecraft.client.renderer.entity.LivingEntityRenderer;
+import net.minecraft.client.renderer.entity.state.AvatarRenderState;
+import net.minecraft.client.renderer.entity.state.LivingEntityRenderState;
+import net.minecraft.client.renderer.state.level.CameraRenderState;
+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.CallbackInfo;
+
+@Mixin(LivingEntityRenderer.class)
+abstract class LivingEntityRendererMixin {
+    @Inject(
+            method = "submit(Lnet/minecraft/client/renderer/entity/state/LivingEntityRenderState;Lcom/mojang/blaze3d/vertex/PoseStack;Lnet/minecraft/client/renderer/SubmitNodeCollector;Lnet/minecraft/client/renderer/state/level/CameraRenderState;)V",
+            at = @At("HEAD")
+    )
+    private void citrus$captureAvatarCamera(
+            LivingEntityRenderState state,
+            PoseStack poseStack,
+            SubmitNodeCollector nodeCollector,
+            CameraRenderState cameraRenderState,
+            CallbackInfo callbackInfo
+    ) {
+        if (state instanceof AvatarRenderState avatarState) {
+            avatarState.setData(CosmeticRenderStateKeys.CAMERA, cameraRenderState);
+        }
+    }
+}

src/main/resources/assets/citrus-dev/geckolib/animations/backpack.animation.json

@@ -0,0 +1,18 @@
+{
+  "format_version": "1.8.0",
+  "animations": {
+    "animation.backpack.idle": {
+      "loop": true,
+      "animation_length": 2.0,
+      "bones": {
+        "flap": {
+          "rotation": {
+            "0.0": [0, 0, 0],
+            "1.0": [2, 0, 0],
+            "2.0": [0, 0, 0]
+          }
+        }
+      }
+    }
+  }
+}

src/main/resources/assets/citrus-dev/geckolib/models/player/backpack.geo.json

@@ -0,0 +1,50 @@
+{
+  "format_version": "1.12.0",
+  "minecraft:geometry": [
+    {
+      "description": {
+        "identifier": "geometry.citrus_backpack",
+        "texture_width": 32,
+        "texture_height": 32,
+        "visible_bounds_width": 2,
+        "visible_bounds_height": 3,
+        "visible_bounds_offset": [0, 1, 0]
+      },
+      "bones": [
+        {
+          "name": "root",
+          "pivot": [0, 0, 0]
+        },
+        {
+          "name": "backpack",
+          "parent": "root",
+          "pivot": [0, 1, 2],
+          "cubes": [
+            {
+              "origin": [-4, 1, 2],
+              "size": [8, 10, 4],
+              "uv": [0, 0]
+            },
+            {
+              "origin": [-3, 3, 6],
+              "size": [6, 5, 1],
+              "uv": [0, 16]
+            }
+          ]
+        },
+        {
+          "name": "flap",
+          "parent": "backpack",
+          "pivot": [0, 2, 6],
+          "cubes": [
+            {
+              "origin": [-3.5, 1, 5.75],
+              "size": [7, 3, 1],
+              "uv": [14, 16]
+            }
+          ]
+        }
+      ]
+    }
+  ]
+}

src/main/resources/citrus-dev.mixins.json

@@ -6,8 +6,10 @@
   "mixins": [
   ],
   "client": [
+    "AvatarRendererMixin",
     "HitboxColorMixin",
     "LightmapRenderStateExtractorMixin",
+    "LivingEntityRendererMixin",
     "MouseHandlerMixin",
     "OwnNametagMixin",
     "PlayerNametagMixin",

src/main/resources/fabric.mod.json

@@ -23,6 +23,7 @@
   "depends": {
     "fabricloader": ">=${loader_version}",
     "fabric-api": "*",
+    "geckolib": ">=5.5.1",
     "minecraft": "${minecraft_version}"
   }
 }