[1.16.3] How to create a custom potion with a custom effect?

[Peerius]

Hello,

 

I tried to create a custom potion with a custom effect and looked at the vanilla code. Someone on YouTube also tried that and used invoke to make a private method accessable. Here is the code:

	private static void addMix(Potion start, Item ingredient, Potion result) {
		if(brewing_mixes == null) {
			brewing_mixes = ObfuscationReflectionHelper.findMethod(PotionBrewing.class, "addMix", Potion.class, Item.class, Potion.class);
			brewing_mixes.setAccessible(true);
		}
		try {
			brewing_mixes.invoke(null, start, ingredient, result);
		} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
			e.printStackTrace();
		} 
	}
	
	public static void addBrewingRecipes() {
		addMix(Potions.AWKWARD, ItemList.nectar, PotionList.love_potion);
	}
	
	public static class ModEffect extends Effect{

		public ModEffect(EffectType typeIn, int liquidColorIn) {
			super(typeIn, liquidColorIn);
		}
		
	}

The addBrewingRecipes() method get's called during the FMLCommonSetupEvent.

But there is something wrong with it, because the invoke method throws an InvocationTargetException. So I guess I need to try it differently. Could someone please give me a hint where I have to start?  

 

Thanks in advance and stay healthy.

[Peerius]

  On 10/10/2020 at 12:35 PM, diesieben07 said:

Look at BrewingRecipeRegistry.

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Okay and how can I transfer specific potions into ItemStacks? 

[Peerius]

  On 10/13/2020 at 7:35 AM, diesieben07 said:

PotionUtils.addPotionToItemStack

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Okay, that helps - thank you. I only have one problem left: register the potion and the effect the right way. Here is what I've done:

	public static void init (){
		EFFECTS.register(FMLJavaModLoadingContext.get().getModEventBus());
		POTIONS.register(FMLJavaModLoadingContext.get().getModEventBus());
		PotionList.addBrewingRecipes();
	}

	
	public static void addBrewingRecipes() {
		BrewingRecipeRegistry.addRecipe(Ingredient.fromStacks(PotionUtils.addPotionToItemStack(ItemStack.EMPTY, Potions.AWKWARD)), Ingredient.fromStacks(new ItemStack(ItemList.nectar)), PotionUtils.addPotionToItemStack(ItemStack.EMPTY, PotionList.LOVE.get()));
	}
	
	public static final DeferredRegister<Effect> EFFECTS = DeferredRegister.create(ForgeRegistries.POTIONS, DeepAffection.modid);
	public static final DeferredRegister<Potion> POTIONS = DeferredRegister.create(ForgeRegistries.POTION_TYPES, DeepAffection.modid);
	
	//Effects
	public static final RegistryObject<Effect> LOVE_EFFECT = EFFECTS.register("love", () -> new ModEffect(EffectType.BENEFICIAL, 0xc98fff).addAttributesModifier(Attributes.field_233821_d_, "55FCED67-E92A-486E-9800-B47F202C4386", (double)0.34F, AttributeModifier.Operation.MULTIPLY_TOTAL));
	
	//Potions
	public static final RegistryObject<Potion> LOVE = POTIONS.register("love", () -> new Potion(new EffectInstance(PotionList.LOVE_EFFECT.get(), 3600)));

When I start the game, I get a NullPointerException because the registry object deepaffection:love is not present. The init() method get's during the instantiation of DeepAffection.

 

Could you please tell me what I did wrong?

 

[Peerius]

  On 10/18/2020 at 1:00 PM, diesieben07 said:

Use FMLCommonSetupEvent to register the recipes. Note that BrewingRecipeRegistry is not threadsafe, so you have to use enqueueWork.

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Okay, now I did this:

	public static void init (){
		EFFECTS.register(FMLJavaModLoadingContext.get().getModEventBus());
		POTIONS.register(FMLJavaModLoadingContext.get().getModEventBus());
	}

	
	public static void addBrewingRecipes(FMLCommonSetupEvent event) {
		System.out.println("PotionList: Brewing Recipes called.");
		event.enqueueWork( () -> {
		BrewingRecipeRegistry.addRecipe(Ingredient.fromStacks(PotionUtils.addPotionToItemStack(ItemStack.EMPTY, Potions.AWKWARD)), Ingredient.fromStacks(new ItemStack(ItemList.nectar)), PotionUtils.addPotionToItemStack(ItemStack.EMPTY, PotionList.LOVE.get()));
		} );
	}
	
	public static final DeferredRegister<Effect> EFFECTS = DeferredRegister.create(ForgeRegistries.POTIONS, DeepAffection.modid);
	public static final DeferredRegister<Potion> POTIONS = DeferredRegister.create(ForgeRegistries.POTION_TYPES, DeepAffection.modid);
	
	//Effects
	public static final RegistryObject<Effect> LOVE_EFFECT = EFFECTS.register("love_effect", () -> new ModEffect(EffectType.BENEFICIAL, 13209599)
			.addAttributesModifier(Attributes.field_233821_d_, "55FCED67-E92A-486E-9800-B47F202C4386", (double)0.34F, AttributeModifier.Operation.MULTIPLY_TOTAL)
			.addAttributesModifier(Attributes.field_233825_h_,"AF8B6E3F-3328-4C0A-AA36-5BA2BB9DBEF3", (double)0.17F, AttributeModifier.Operation.MULTIPLY_TOTAL)
			.addAttributesModifier(Attributes.field_233818_a_, "5D6F0BA2-1186-46AC-B896-C61C5CEE99CC", 10.0D, AttributeModifier.Operation.ADDITION)
			.addAttributesModifier(Attributes.field_233828_k_, "03C3C89D-7037-4B42-869F-B146BCB64D2E", 1.0D, AttributeModifier.Operation.ADDITION));
	
	//Potions
	public static final RegistryObject<Potion> LOVE = POTIONS.register("love", () -> new Potion(new EffectInstance(PotionList.LOVE_EFFECT.get(), 6000)));

My potion works now, but I can't brew it yet. Did I do something wrong with the enqueueWork?

[Peerius]

  On 10/21/2020 at 10:37 AM, diesieben07 said:

You are adding potions to the empty ItemStack (or trying to, rather). You need to create a new ItemStack of Items.POTION.

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Ah okay, I didn't know what exactly to use there. Thank you very much, it works now!