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Minecraft 1.19.4 -> 1.20 Forge Mod Migration Primer

This is a high level, non-exhaustive overview on how to migrate your mod from 1.19.4 to 1.20 using Forge. All provided names use the official mojang mappings.

This primer is licensed under the Creative Commons Attribution 4.0 International, so feel free to use it as a reference and leave a link so that other readers can consume the primer.

If there's any incorrect or missing information, please file an issue on this repository or ping @ChampionAsh5357 in the Neoforged Discord server.

Vanilla Changes​

Vanilla changes are listed here.

Creative Tab Registry​

Nw tabs can be registered using one of the register methods while adding to existing tabs is done via BuildCreativeModeTabContentsEvent on the mod event bus. For new tabs, Forge patches in the ability to order tabs via CreativeModeTab$Builder#withTabsBefore and #withTabsAfter.

// Registered on the MOD event bus
// Assume we have RegistryObject<Item> and RegistryObject<Block> called ITEM and BLOCK
@SubscribeEvent
public void buildContents(BuildCreativeModeTabContentsEvent event) {
    // Add to ingredients tab
    if (event.getTabKey() == CreativeModeTabs.INGREDIENTS) {
        event.accept(ITEM);
        event.accept(BLOCK); // Takes in an ItemLike, assumes block has registered item
    }
}

Forge Config: Resource Pack Caching Removal​

All entries related to resource pack caching were removed from the Forge common config. Vanilla now handles this by default.

Forge Capability Class Removals​

The Capability* which originally held the Forge capabilities have been removed. All calls should be delegated to ForgeCapabilities instead.

Forge Network Message Consumers​

Within the message builder for Forge networks, the #consumer, which handles the message logic, has been removed. Now, it has been broken into #consumerNetworkThread and #consumerMainThread. These methods determine whether the logic should be handled directly on the network thread or delegated to the consumer itself.

#consumerMainThread handles the packet for you, so it only accepts a BiConsumer.

public void mainThreadMessage(MSG message, Supplier<NetworkEvent.Context> ctx) { /**/ }

#consumerNetworkThread can take in a BiConsumer or ToBooleanBiFunction depending on if you want to handle the packet via #setPacketHandled or using the return statement, respectively.

public void networkThreadMessageC(MSG message, Supplier<NetworkEvent.Context> ctx) { 
    // ...
    ctx.get().setPacketHandled(true);
}

public boolean networkThreadMessageF(MSG message, Supplier<NetworkEvent.Context> ctx) { 
    // ...
    return true;
}

Removal of Dummy Entries​

Forge dummy entries handled by Forge registries have been completely removed.

New Tags​

  • Item Tag forge:tools/swords -> minecraft:swords
  • Item Tag forge:tools/axes -> minecraft:axes
  • Item Tag forge:tools/pickaxes -> minecraft:pickaxes
  • Item Tag forge:tools/shovels -> minecraft:shovels
  • Item Tag forge:tools/hoes -> minecraft:hoes

Minor Changes and Renames​

  • net.minecraftforge.event.entity.player.PlayerEvent$BreakSpeed#getPos -> #getPosition which now takes in an Optional<BlockPos>
  • net.minecraftforge.client.event.RenderLevelLastEvent -> RenderLevelStageEvent
    • There is no direct translation between the events. You need to choose which stage suits your logic best.
  • net.miencraftforge.common.world.ModifiableBiomeInfo$BiomeInfo$Builder#getEffects -> #getSpecialEffects
  • net.miencraftforge.client.extensions.IForgeTransformation#push -> IForgePoseStack#pushTransformation
  • net.minecraftforge.client.event.RegisterParticleProvidersEvent#register -> #registerSpecial, #registerSprite, #registerSpriteSet respectively
  • net.minecraftforge.common.extensions.IForgePlayer#getAttackRange -> #getEntityReach
    • ForgeMod#REACH_DISTANCE -> #BLOCK_REACH
  • net.minecraftforge.common.extensions.IForgePlayer#getReachDistance -> #getBlockReach
    • ForgeMod#ATTACK_RANGE -> #ENTITY_REACH
  • net.minecraftforge.common.extensions.IForgePlayer#canHit and #canInteractWith -> #canReach
  • net.minecraftforge.event.entity.living.LivingSetAttackTargetEvent -> LivingChangeTargetEvent
  • net.minecraftforge.client.model.generators.BlockModelBuilder#rootTransform -> #rootTransforms
    • All root transformation logic has been moved to ModelBuilder and TransformationHelper
  • net.minecraftforge.common.extensions.IForgeItem#onUsingTick -> Item#onUseTick
  • net.minecraftforge.event.level.SaplingGrowTreeEvent -> BlockGrowFeatureEvent
  • net.minecraftforge.client.model.IQuadTransformer#empty, #applying, and #applyingLightmap moved to QuadTransformers
  • net.minecraftforge.client.gui.ScreenUtils has all been moved to extension methods on GuiGraphics
    • #drawTexturedModalRect and #drawGradientRect have been replaced with #blit and #fillGradient, respectively