done with GLM

src/generated/resources/.cache/95bb3a2eea1b1ca79b1089cc135e8d6882c6b2ad

@@ -0,0 +1,4 @@
+// 1.21	2024-08-08T05:47:34.865233	Global Loot Modifiers : tutorialmod
+60641db777c2d35cc872ccfc7cc7480e72559477 data/neoforge/loot_modifiers/global_loot_modifiers.json
+7c8fa841a46c131d5b9d58923260f8681ecbe5fd data/tutorialmod/loot_modifiers/example_item_from_igloo_chest.json
+a891e805643031c2b80b813521b72a35c95121b2 data/tutorialmod/loot_modifiers/example_item_from_iron_golem.json

src/generated/resources/data/neoforge/loot_modifiers/global_loot_modifiers.json

@@ -0,0 +1,7 @@
+{
+  "entries": [
+    "tutorialmod:example_item_from_igloo_chest",
+    "tutorialmod:example_item_from_iron_golem"
+  ],
+  "replace": false
+}

src/generated/resources/data/tutorialmod/loot_modifiers/example_item_from_igloo_chest.json

@@ -0,0 +1,14 @@
+{
+  "type": "tutorialmod:add_item",
+  "conditions": [
+    {
+      "condition": "neoforge:loot_table_id",
+      "loot_table_id": "minecraft:chests/igloo_chest"
+    },
+    {
+      "chance": 0.35,
+      "condition": "minecraft:random_chance"
+    }
+  ],
+  "item": "tutorialmod:example_item"
+}

src/generated/resources/data/tutorialmod/loot_modifiers/example_item_from_iron_golem.json

@@ -0,0 +1,10 @@
+{
+  "type": "tutorialmod:add_item",
+  "conditions": [
+    {
+      "condition": "neoforge:loot_table_id",
+      "loot_table_id": "minecraft:entities/iron_golem"
+    }
+  ],
+  "item": "tutorialmod:example_item"
+}

src/main/java/io/github/realyusufismail/TutorialMod.java

@@ -4,6 +4,7 @@
 import io.github.realyusufismail.init.BlockInit;
 import io.github.realyusufismail.init.CreativeModeTabInit;
 import io.github.realyusufismail.init.ItemInit;
+import io.github.realyusufismail.init.LootModifierInit;
 import net.neoforged.bus.api.IEventBus;
 import net.neoforged.fml.ModList;
 import net.neoforged.fml.common.Mod;
@@ -21,6 +22,7 @@ public TutorialMod(@NotNull IEventBus bus) {
         ItemInit.ITEMS.register(bus);
         BlockInit.BLOCKS.register(bus);
         CreativeModeTabInit.CREATIVE_MODE_TABS.register(bus);
+        LootModifierInit.LOOT_MODIFIERS.register(bus);
 
         bus.addListener(DataGenerators::gatherData);
 

src/main/java/io/github/realyusufismail/data/DataGenerators.java

@@ -2,6 +2,7 @@
 
 import io.github.realyusufismail.TutorialMod;
 import io.github.realyusufismail.data.lang.ModEnLangProvider;
+import io.github.realyusufismail.data.loot.ModGlobalLootModifiersProvider;
 import io.github.realyusufismail.data.loottable.ModLootTables;
 import io.github.realyusufismail.data.recipe.MainModRecipeProvider;
 import io.github.realyusufismail.data.tag.ModBlockTagsProvider;
@@ -31,6 +32,7 @@ public static void gatherData(GatherDataEvent event) {
             generator.addProvider(true, new ModLootTables(output, event.getLookupProvider()));
             generator.addProvider(true, new ModWorldGenProvider(output, event.getLookupProvider()));
             generator.addProvider(true, new MainModRecipeProvider(generator, event.getLookupProvider()));
+            generator.addProvider(true, new ModGlobalLootModifiersProvider(output, event.getLookupProvider()));
         } catch (RuntimeException e) {
             TutorialMod.logger.error("Failed to gather data", e);
         }

src/main/java/io/github/realyusufismail/data/loot/ModGlobalLootModifiersProvider.java

@@ -0,0 +1,33 @@
+package io.github.realyusufismail.data.loot;
+
+import io.github.realyusufismail.TutorialMod;
+import io.github.realyusufismail.init.ItemInit;
+import io.github.realyusufismail.loot.AddItemModifier;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.data.PackOutput;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.level.storage.loot.predicates.LootItemCondition;
+import net.minecraft.world.level.storage.loot.predicates.LootItemRandomChanceCondition;
+import net.neoforged.neoforge.common.data.GlobalLootModifierProvider;
+import net.neoforged.neoforge.common.loot.LootTableIdCondition;
+
+import java.util.concurrent.CompletableFuture;
+
+// see https://github.com/Luohuayu/CatServer/blob/1c92118fcca69ffac97a48c8e1f6e1bb861b41d1/src/main/java/org/bukkit/loot/LootTables.java#L71 for some loot tables
+public class ModGlobalLootModifiersProvider extends GlobalLootModifierProvider {
+    public ModGlobalLootModifiersProvider(PackOutput output, CompletableFuture<HolderLookup.Provider> registries) {
+        super(output, registries, TutorialMod.MOD_ID);
+    }
+
+    @Override
+    protected void start() {
+        add("example_item_from_igloo_chest", new AddItemModifier(new LootItemCondition[]{
+                LootTableIdCondition.builder(ResourceLocation.parse("chests/igloo_chest")).build(),
+                LootItemRandomChanceCondition.randomChance(0.35f).build()},
+                ItemInit.EXAMPLE_ITEM.get()));
+
+        add("example_item_from_iron_golem", new AddItemModifier(new LootItemCondition[]{
+                LootTableIdCondition.builder(ResourceLocation.parse("entities/iron_golem")).build()},
+                ItemInit.EXAMPLE_ITEM.get()));
+    }
+}

src/main/java/io/github/realyusufismail/init/LootModifierInit.java

@@ -0,0 +1,15 @@
+package io.github.realyusufismail.init;
+
+import com.mojang.serialization.MapCodec;
+import io.github.realyusufismail.TutorialMod;
+import io.github.realyusufismail.loot.AddItemModifier;
+import net.neoforged.neoforge.common.loot.IGlobalLootModifier;
+import net.neoforged.neoforge.registries.DeferredHolder;
+import net.neoforged.neoforge.registries.DeferredRegister;
+import net.neoforged.neoforge.registries.NeoForgeRegistries;
+
+public class LootModifierInit {
+    public static DeferredRegister<MapCodec<? extends IGlobalLootModifier>> LOOT_MODIFIERS = DeferredRegister.create(NeoForgeRegistries.GLOBAL_LOOT_MODIFIER_SERIALIZERS, TutorialMod.MOD_ID);
+
+    public static final DeferredHolder<MapCodec<? extends IGlobalLootModifier>, MapCodec<AddItemModifier>> ADD_ITEM_MODIFIER = LOOT_MODIFIERS.register("add_item", AddItemModifier.CODEC_SUPPLIER);
+}

src/main/java/io/github/realyusufismail/loot/AddItemModifier.java

@@ -0,0 +1,49 @@
+package io.github.realyusufismail.loot;
+
+import com.google.common.base.Suppliers;
+import com.mojang.serialization.MapCodec;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import it.unimi.dsi.fastutil.objects.ObjectArrayList;
+import net.minecraft.core.registries.BuiltInRegistries;
+import net.minecraft.world.item.Item;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.storage.loot.LootContext;
+import net.minecraft.world.level.storage.loot.predicates.LootItemCondition;
+import net.neoforged.neoforge.common.loot.IGlobalLootModifier;
+import net.neoforged.neoforge.common.loot.LootModifier;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.function.Supplier;
+
+public class AddItemModifier extends LootModifier {
+
+    public static Supplier<MapCodec<AddItemModifier>> CODEC_SUPPLIER = Suppliers.memoize(() -> RecordCodecBuilder
+            .mapCodec(instance -> AddItemModifier.codecStart(instance)
+            .and(BuiltInRegistries.ITEM.byNameCodec().fieldOf("item")
+                    .forGetter(addItemModifierInstance -> addItemModifierInstance.item))
+            .apply(instance, AddItemModifier::new)));
+
+    private final Item item;
+
+    public AddItemModifier(LootItemCondition[] conditionsIn, Item item) {
+        super(conditionsIn);
+        this.item = item;
+    }
+
+    @Override
+    protected @NotNull ObjectArrayList<ItemStack> doApply(ObjectArrayList<ItemStack> generatedLoot, LootContext context) {
+        for (LootItemCondition condition : this.conditions) {
+            if (!condition.test(context)) {
+                return generatedLoot;
+            }
+        }
+
+        generatedLoot.add(new ItemStack(this.item));
+        return generatedLoot;
+    }
+
+    @Override
+    public MapCodec<? extends IGlobalLootModifier> codec() {
+        return CODEC_SUPPLIER.get();
+    }
+}