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Dynamic Loot Modification (view source)

Revision as of 18:30, 20 September 2022

668 bytes added ,  18:30, 20 September 2022
Fix the explanation
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#* This will contain all of the data about your modification and allows data packs to tweak your effect.
 
#* This will contain all of the data about your modification and allows data packs to tweak your effect.
 
# A class that extends <code>LootModifier</code>
 
# A class that extends <code>LootModifier</code>
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#* The operational code that makes your modifier work and associated serializer.
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#* The operational code that makes your modifier work and associated codec.
   −
Finally, the serializer for your operational class is [[Registration|registered]] as any other <code>ForgeRegistryEntry</code>.
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Finally, the codec for your operational class is [[Registration|registered]] as any other registry object.
    
==The global_loot_modifiers.json==
 
==The global_loot_modifiers.json==
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     },
 
     },
 
     {
 
     {
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       "condition": "block_state_property",
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       "condition": "minecraft:block_state_property",
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       "block":"minecraft:wheat"
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       "block": "minecraft:wheat"
 
     }
 
     }
 
   ],
 
   ],
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{{Tip|<code>conditions</code> is the only object needed by the system specification, everything else is the mod maker's data.   
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{{Tip|<code>conditions</code> is the only object needed by the system specification, everything else is the mod maker's data.  
 +
   
 
<code>seedItem</code>, <code>numSeeds</code> and <code>replacement</code> are NOT standard elements of Global Loot Modifiers.   
 
<code>seedItem</code>, <code>numSeeds</code> and <code>replacement</code> are NOT standard elements of Global Loot Modifiers.   
 +
 
They are deserialized manually in the next section.}}
 
They are deserialized manually in the next section.}}
    
== The LootModifier Subclass ==
 
== The LootModifier Subclass ==
   −
You will also need a static child class that extends <code>GlobalLootModifierSerializer<T></code> where <code>T</code> is your LootModifier subclass in order to deserialize your json data file into operational code.
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You will also need a <code>Codec<T></code> where <code>T</code> is your LootModifier subclass in order to deserialize your json data file into operational code. The codec must be [[Registration|registered]].
    
<syntaxhighlight lang="java">
 
<syntaxhighlight lang="java">
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private static class WheatSeedsConverterModifier extends LootModifier {
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/**
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private final int numSeedsToConvert;
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    * When harvesting wheat with shears, this modifier is invoked via the wheat_harvest loot_modifier json<br/>
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private final Item itemToCheck;
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    * This modifier checks how many seeds were harvested and turns X seeds into Y wheat (3:1)
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private final Item itemReward;
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    *
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public WheatSeedsConverterModifier(ILootCondition[] conditionsIn, int numSeeds, Item itemCheck, Item reward) {
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    */
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super(conditionsIn);
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// Assume there exists a <code>IForgeRegistry<Codec<T extends LootModifier>></code> LOOT_MODIFIER_REGISTRAR added by a mod
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numSeedsToConvert = numSeeds;
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private static class WheatSeedsConverterModifier extends LootModifier
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itemToCheck = itemCheck;
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{
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itemReward = reward;
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        public static final RegistryObject<Codec<WheatSeedsConverterModifier>> CODEC = LOOT_MODIFIER_REGISTRAR.register("wheat_seeds_converter", () ->
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}
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        RecordCodecBuilder.create(inst -> codecStart(inst).and(
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                inst.group(
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                        Codec.INT.fieldOf("numSeeds").forGetter(m -> m.numSeedsToConvert),
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                        ForgeRegistries.ITEMS.getCodec().fieldOf("seedItem").forGetter(m -> m.itemToCheck),
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                        ForgeRegistries.ITEMS.getCodec().fieldOf("replacement").forGetter(m -> m.itemReward)
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                )).apply(inst, WheatSeedsConverterModifier::new)
 +
        ));
   −
@Nonnull
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        private final int numSeedsToConvert;
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@Override
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        private final Item itemToCheck;
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public List<ItemStack> doApply(List<ItemStack> generatedLoot, LootContext context) {
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        private final Item itemReward;
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/*
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        public WheatSeedsConverterModifier(LootItemCondition[] conditionsIn, int numSeeds, Item itemCheck,
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* Additional conditions can be checked, though as much as possible should be parameterized via JSON data.
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            Item reward)
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* It is better to write a new ILootCondition implementation than to do things here.
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        {
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*/
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            super(conditionsIn);
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int numSeeds = 0;
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            numSeedsToConvert = numSeeds;
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for(ItemStack stack : generatedLoot) {
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            itemToCheck = itemCheck;
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if(stack.getItem() == itemToCheck)
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            itemReward = reward;
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numSeeds+=stack.getCount();
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        }
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}
  −
if(numSeeds >= numSeedsToConvert) {
  −
generatedLoot.removeIf(x -> x.getItem() == itemToCheck);
  −
generatedLoot.add(new ItemStack(itemReward, (numSeeds/numSeedsToConvert)));
  −
numSeeds = numSeeds%numSeedsToConvert;
  −
if(numSeeds > 0)
  −
generatedLoot.add(new ItemStack(itemToCheck, numSeeds));
  −
}
  −
return generatedLoot;
  −
}
     −
private static class Serializer extends GlobalLootModifierSerializer<WheatSeedsConverterModifier> {
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        @NotNull
 +
        @Override
 +
        public ObjectArrayList<ItemStack> doApply(ObjectArrayList<ItemStack> generatedLoot, LootContext context) {
 +
            //
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            // Additional conditions can be checked, though as much as possible should be parameterized via JSON data.
 +
            // It is better to write a new ILootCondition implementation than to do things here.
 +
            //
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            int numSeeds = 0;
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            generatedLoot.stream().filter(stack -> stack.getItem() == itemToCheck)
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                  .forEach(stack -> numSeeds+=stack.getCount())
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            if(numSeeds >= numSeedsToConvert) {
 +
                generatedLoot.removeIf(x -> x.getItem() == itemToCheck);
 +
                generatedLoot.add(new ItemStack(itemReward, (numSeeds/numSeedsToConvert)));
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                numSeeds = numSeeds%numSeedsToConvert;
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                if(numSeeds > 0)
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                    generatedLoot.add(new ItemStack(itemToCheck, numSeeds));
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            }
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            return generatedLoot;
 +
        }
   −
@Override
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        @Override
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public WheatSeedsConverterModifier read(ResourceLocation name, JsonObject object, ILootCondition[] conditionsIn) {
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        public Codec<? extends IGlobalLootModifier> codec() {
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int numSeeds = JSONUtils.getInt(object, "numSeeds");
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            return CODEC.get();
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Item seed = ForgeRegistries.ITEMS.getValue(new ResourceLocation((JSONUtils.getString(object, "seedItem"))));
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        }
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Item wheat = ForgeRegistries.ITEMS.getValue(new ResourceLocation(JSONUtils.getString(object, "replacement")));
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    }
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return new WheatSeedsConverterModifier(conditionsIn, numSeeds, seed, wheat);
  −
}
  −
}
  −
}
   
</syntaxhighlight>
 
</syntaxhighlight>
    
The critical portion is the <code>doApply</code> method.
 
The critical portion is the <code>doApply</code> method.
   −
This method is only called if the <code>conditions</code> specified return <code>true</code> and the modder is now able to make the modifications they desire. In this case we can see that the number of <code>itemToCheck</code> meets or exceeds the <code>numSeedsToConvert</code> before modifying the list by adding an <code>itemReward</code> and removing any excess <code>itemToCheck</code> stacks, matching the previously mentioned effects: When a wheat block is harvested with shears, if enough seeds are generated as loot, they are converted to additional wheat instead.
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This method is only called if the <code>conditions</code> specified return <code>true</code> and the modder is now able to make the modifications they desire. In this case we can see that the number of <code>itemToCheck</code> meets or exceeds the <code>numSeedsToConvert</code> before modifying the list by adding an <code>itemReward</code> and removing any excess <code>itemToCheck</code> stacks, matching the previously mentioned effects: ''When a wheat block is harvested with shears, if enough seeds are generated as loot, they are converted to additional wheat instead''.
   −
Also take note of the <code>read</code> method in the serializer. The conditions are already deserialized for you and if you have no other data, simply <code>return new MyModifier(conditionsIn)</code>. However, the full <code>JsonObject</code> is available if needed.
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The codec can also be used for [[datageneration|data generation]] with a <code>GlobalLootModifierProvider</code>.
   −
Additional [https://github.com/MinecraftForge/MinecraftForge/blob/1.15.x/src/test/java/net/minecraftforge/debug/gameplay/loot/GlobalLootModifiersTest.java examples] can be found on the Forge Git repository, including silk touch and smelting effects.
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Additional [https://github.com/MinecraftForge/MinecraftForge/blob/1.19.x/src/test/java/net/minecraftforge/debug/gameplay/loot/GlobalLootModifiersTest.java examples] can be found on the Forge Git repository, including silk touch and smelting effects.
Retrieved from ‘https://forge.gemwire.uk/wiki/Special:MobileDiff/2828...3329’