Environment attribute API for adding custom attribute layers

fabric-environment-attributes-v1/build.gradle

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+version = getSubprojectVersion(project)
+
+moduleDependencies(project, [
+	'fabric-api-base',
+	'fabric-lifecycle-events-v1'
+])
+
+testDependencies(project, [
+	':fabric-resource-loader-v1',
+	':fabric-client-gametest-api-v1'
+])

fabric-environment-attributes-v1/src/main/java/net/fabricmc/fabric/api/environment/attribute/v1/AttributeLayerPosition.java

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+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
+package net.fabricmc.fabric.api.environment.attribute.v1;
+
+/**
+ * Positions at which environment attribute layers can be inserted. Each position is associated with an event in
+ * {@link EnvironmentAttributeEvents}. The enum is ordered by in which order Minecraft adds its default layers.
+ */
+public enum AttributeLayerPosition {
+	/**
+	 * The position before all vanilla layers.
+	 */
+	BEFORE_ALL,
+
+	/**
+	 * The position between dimension and biome layers.
+	 */
+	BETWEEN_DIMENSION_AND_BIOMES,
+
+	/**
+	 * The position between biome and timeline layers.
+	 */
+	BETWEEN_BIOMES_AND_TIMELINES,
+
+	/**
+	 * The position between timeline and weather layers.
+	 */
+	BETWEEN_TIMELINES_AND_WEATHER,
+
+	/**
+	 * The position after all vanilla layers.
+	 */
+	AFTER_ALL
+}

fabric-environment-attributes-v1/src/main/java/net/fabricmc/fabric/api/environment/attribute/v1/EnvironmentAttributeEvents.java

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+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
+package net.fabricmc.fabric.api.environment.attribute.v1;
+
+import net.minecraft.world.attribute.EnvironmentAttributeSystem;
+import net.minecraft.world.level.Level;
+
+import net.fabricmc.fabric.api.event.Event;
+import net.fabricmc.fabric.impl.environment.attribute.EnvironmentAttributeEventsImpl;
+
+/**
+ * Events related to environment attributes.
+ */
+public class EnvironmentAttributeEvents {
+	/**
+	 * Returns the {@link InsertLayers} event for the given {@link AttributeLayerPosition}. This event allows inserting
+	 * extra attribute layers at that position during the environment attribute setup for a {@link Level}. By default,
+	 * Minecraft adds layers for the dimension, then for biomes, then for timelines and lastly for weather. The event
+	 * returned by this method is triggered before, in between and after each of these vanilla layers, depending on the
+	 * selected position, in the following manner:
+	 * <ul>
+	 * <li>Event for {@link AttributeLayerPosition#BEFORE_ALL} is triggered.</li>
+	 * <li>Minecraft adds the layer for dimension type attribute configurations.</li>
+	 * <li>Event for {@link AttributeLayerPosition#BETWEEN_DIMENSION_AND_BIOMES} is triggered.</li>
+	 * <li>Minecraft adds the layer for biome attribute configurations.</li>
+	 * <li>Event for {@link AttributeLayerPosition#BETWEEN_BIOMES_AND_TIMELINES} is triggered.</li>
+	 * <li>Minecraft adds the layer for timeline attribute animations.</li>
+	 * <li>Event for {@link AttributeLayerPosition#BETWEEN_TIMELINES_AND_WEATHER} is triggered.</li>
+	 * <li>Minecraft adds the layer for some hardcoded weather attribute overrides.</li>
+	 * <li>Event for {@link AttributeLayerPosition#AFTER_ALL} is triggered.</li>
+	 * </ul>
+	 * @param position The position at which you want to insert attribute layers.
+	 * @return The event to listen for layer setup.
+	 */
+	public static Event<InsertLayers> insertLayersEvent(AttributeLayerPosition position) {
+		return EnvironmentAttributeEventsImpl.getOrCreateInsertLayersEvent(position);
+	}
+
+	/**
+	 * Callback for events returned from {@link #insertLayersEvent}.
+	 */
+	public interface InsertLayers {
+		/**
+		 * Insert custom attribute layers into the {@link EnvironmentAttributeSystem.Builder}.
+		 * @param systemBuilder The environment attribute system builder to modify.
+		 * @param level The level for which the attribute system is built.
+		 */
+		void insertAttributeLayers(EnvironmentAttributeSystem.Builder systemBuilder, Level level);
+	}
+}

fabric-environment-attributes-v1/src/main/java/net/fabricmc/fabric/impl/environment/attribute/EnvironmentAttributeEventsImpl.java

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+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
+package net.fabricmc.fabric.impl.environment.attribute;
+
+import java.util.EnumMap;
+import java.util.Map;
+
+import org.jspecify.annotations.NonNull;
+
+import net.minecraft.world.attribute.EnvironmentAttributeSystem;
+import net.minecraft.world.level.Level;
+
+import net.fabricmc.fabric.api.environment.attribute.v1.AttributeLayerPosition;
+import net.fabricmc.fabric.api.environment.attribute.v1.EnvironmentAttributeEvents;
+import net.fabricmc.fabric.api.event.Event;
+import net.fabricmc.fabric.api.event.EventFactory;
+
+public class EnvironmentAttributeEventsImpl {
+	private static final Map<AttributeLayerPosition, Event<EnvironmentAttributeEvents.InsertLayers>> POSITION_EVENT_MAP = new EnumMap<>(AttributeLayerPosition.class);
+
+	@NonNull
+	public static Event<EnvironmentAttributeEvents.InsertLayers> getOrCreateInsertLayersEvent(AttributeLayerPosition position) {
+		return POSITION_EVENT_MAP.computeIfAbsent(position, (p -> createInsertEvent()));
+	}
+
+	public static void insertLayers(AttributeLayerPosition position, EnvironmentAttributeSystem.Builder systemBuilder, Level level) {
+		Event<EnvironmentAttributeEvents.InsertLayers> event = POSITION_EVENT_MAP.get(position);
+
+		if (event != null) {
+			event.invoker().insertAttributeLayers(systemBuilder, level);
+		}
+	}
+
+	private static Event<EnvironmentAttributeEvents.InsertLayers> createInsertEvent() {
+		return EventFactory.createArrayBacked(EnvironmentAttributeEvents.InsertLayers.class, callbacks -> (systemBuilder, level) -> {
+			for (EnvironmentAttributeEvents.InsertLayers callback : callbacks) {
+				callback.insertAttributeLayers(systemBuilder, level);
+			}
+		});
+	}
+}

fabric-environment-attributes-v1/src/main/java/net/fabricmc/fabric/mixin/environment/attribute/EnvironmentAttributeSystemMixin.java

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+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
+package net.fabricmc.fabric.mixin.environment.attribute;
+
+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 net.minecraft.world.attribute.EnvironmentAttributeSystem;
+import net.minecraft.world.level.Level;
+
+import net.fabricmc.fabric.api.environment.attribute.v1.AttributeLayerPosition;
+import net.fabricmc.fabric.impl.environment.attribute.EnvironmentAttributeEventsImpl;
+
+@Mixin(EnvironmentAttributeSystem.class)
+public class EnvironmentAttributeSystemMixin {
+	@Inject(
+			method = "addDefaultLayers",
+			at = @At(value = "HEAD")
+	)
+	private static void addLayersBeforeAll(EnvironmentAttributeSystem.Builder builder, Level level, CallbackInfo ci) {
+		EnvironmentAttributeEventsImpl.insertLayers(AttributeLayerPosition.BEFORE_ALL, builder, level);
+	}
+
+	@Inject(
+			method = "addDefaultLayers",
+			at = @At(value = "INVOKE", target = "Lnet/minecraft/world/attribute/EnvironmentAttributeSystem;addBiomeLayer(Lnet/minecraft/world/attribute/EnvironmentAttributeSystem$Builder;Lnet/minecraft/core/HolderLookup;Lnet/minecraft/world/level/biome/BiomeManager;)V")
+	)
+	private static void addLayersAfterDimension(EnvironmentAttributeSystem.Builder builder, Level level, CallbackInfo ci) {
+		EnvironmentAttributeEventsImpl.insertLayers(AttributeLayerPosition.BETWEEN_DIMENSION_AND_BIOMES, builder, level);
+	}
+
+	@Inject(
+			method = "addDefaultLayers",
+			at = @At(value = "INVOKE", target = "Lnet/minecraft/world/level/Level;dimensionType()Lnet/minecraft/world/level/dimension/DimensionType;")
+	)
+	private static void addLayersAfterBiomes(EnvironmentAttributeSystem.Builder builder, Level level, CallbackInfo ci) {
+		EnvironmentAttributeEventsImpl.insertLayers(AttributeLayerPosition.BETWEEN_BIOMES_AND_TIMELINES, builder, level);
+	}
+
+	@Inject(
+			method = "addDefaultLayers",
+			at = @At(value = "INVOKE", target = "Lnet/minecraft/world/level/Level;canHaveWeather()Z")
+	)
+	private static void addLayersAfterTimelines(EnvironmentAttributeSystem.Builder builder, Level level, CallbackInfo ci) {
+		EnvironmentAttributeEventsImpl.insertLayers(AttributeLayerPosition.BETWEEN_TIMELINES_AND_WEATHER, builder, level);
+	}
+
+	@Inject(
+			method = "addDefaultLayers",
+			at = @At(value = "TAIL")
+	)
+	private static void addLayersAfterAll(EnvironmentAttributeSystem.Builder builder, Level level, CallbackInfo ci) {
+		EnvironmentAttributeEventsImpl.insertLayers(AttributeLayerPosition.AFTER_ALL, builder, level);
+	}
+}

fabric-environment-attributes-v1/src/main/resources/fabric-environment-attributes-v1.mixins.json

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+{
+  "required": true,
+  "package": "net.fabricmc.fabric.mixin.environment.attribute",
+  "compatibilityLevel": "JAVA_25",
+  "mixins": [
+    "EnvironmentAttributeSystemMixin"
+  ],
+  "injectors": {
+    "defaultRequire": 1
+  },
+  "overwrites": {
+    "requireAnnotations": true
+  }
+}

fabric-environment-attributes-v1/src/main/resources/fabric.mod.json

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+{
+  "schemaVersion": 1,
+  "id": "fabric-environment-attributes-v1",
+  "name": "Fabric Environment Attributes API (v1)",
+  "version": "${version}",
+  "license": "Apache-2.0",
+  "icon": "assets/fabric-environment-attributes-v1/icon.png",
+  "contact" : {
+    "homepage": "https://fabricmc.net",
+    "irc": "irc://irc.esper.net:6667/fabric",
+    "issues": "https://github.com/FabricMC/fabric/issues",
+    "sources": "https://github.com/FabricMC/fabric"
+  },
+  "authors": [
+    "FabricMC"
+  ],
+  "entrypoints": {
+  },
+  "depends": {
+    "fabricloader": ">=0.18.4",
+    "minecraft": ">=1.16-rc.3",
+    "fabric-api-base": "*"
+  },
+  "description": "Fabric Environment Attributes API.",
+  "mixins": [
+    "fabric-environment-attributes-v1.mixins.json"
+  ],
+  "custom": {
+    "fabric-api:module-lifecycle": "stable"
+  }
+}

fabric-environment-attributes-v1/src/testmod/java/net/fabricmc/fabric/test/environment/attribute/FabricEnvironmentAttributesTest.java

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+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
+package net.fabricmc.fabric.test.environment.attribute;
+
+import net.minecraft.core.Registry;
+import net.minecraft.core.registries.BuiltInRegistries;
+import net.minecraft.resources.Identifier;
+import net.minecraft.world.attribute.AttributeTypes;
+import net.minecraft.world.attribute.EnvironmentAttribute;
+
+import net.fabricmc.api.ModInitializer;
+
+public class FabricEnvironmentAttributesTest implements ModInitializer {
+	public static final EnvironmentAttribute<Integer> TEST_COLOR = EnvironmentAttribute.builder(AttributeTypes.RGB_COLOR)
+			.defaultValue(0xFFFFFF)
+			.syncable()
+			.build();
+
+	@Override
+	public void onInitialize() {
+		Registry.register(BuiltInRegistries.ENVIRONMENT_ATTRIBUTE, Identifier.fromNamespaceAndPath("fabric_environment_attributes", "test_color"), TEST_COLOR);
+	}
+}

fabric-environment-attributes-v1/src/testmod/resources/fabric.mod.json

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+{
+  "schemaVersion": 1,
+  "id": "fabric-environment-attributes-v1-testmod",
+  "name": "Fabric Environment Attributes (v1) Test Mod",
+  "version": "1.0.0",
+  "environment": "*",
+  "license": "Apache-2.0",
+  "depends": {
+    "fabric-environment-attributes-v1": "*"
+  },
+  "entrypoints": {
+    "main": [
+      "net.fabricmc.fabric.test.environment.attribute.FabricEnvironmentAttributesTest"
+    ],
+    "fabric-client-gametest": [
+      "net.fabricmc.fabric.test.environment.attribute.client.FabricEnvironmentAttributesClientTest"
+    ]
+  }
+}