Technical News in Minecraft 1.19.3 – fillbiome Command, New Predicates!

Ladies and gentlemen, Minecraft 1.19.3 is here and in addition to all the gameplay changes, this version also contains a new command, new capabilities for data packs, new functionality for custom heads and more. My name is slicedlime and in this video I’ll take you through all the technical changes.

Let’s start with the new command – it is called fillbiome and works similarly to the fill command, except it sets the biome instead of the block type. You specify two corners of a volume just like with the fill command, and you can also filter

By the current biome by adding a replace parameter at the end of the command. One major difference from the fill command is that the game only saves biomes every 4 blocks, which means that the coordinates you specify will not apply perfectly.

In between those 4 blocks, the game will extrapolate biomes using some additional noise, so you’ll get a somewhat jagged edge. Another related change is a new sub-command for execute – execute if or unless biome, followed by a location and a biome id or biome tag id, which continues the execution if or

Unless the location matches that biome. When loading into a world or reloading a datapack, functions in the “load” function tag now run before functions in the “tick” function tag. And an optimization has been made to selectors with the arbitrary sort order and some limit

Of results, meaning the game now properly stops looking up more results when enough results have been found. The publish command in singleplayer has also been expanded and now has new arguments letting you specify the port, enable commands and set the game mode just like on the open to LAN screen.

All the new parameters are optional. There are also new game rules in this version – they’re included in my gameplay update video since they’re also selectable from the create new world screen, so go check them out in that video if you haven’t already seen it.

In pack format news, translation files and pack.mcmeta files now include non-ascii characters directly encoded as UTF-8 rather than including them as escape sequences. Feature flags have also been added. A feature flag is an id enabling a hardcoded set of features in the game.

Such flags are enabled by datapacks in a new metadata section called features, which has a list called enabled listing the desired flags. These flags are then stored inside the world file and can never be disabled, and packs loaded after world creation will not enable new flags.

There are a number of effects of feature flags. For blocks, disabled block IDs are not recognized by commands that can create new blocks such as setblock and fill. Block items for disabled blocks are also disabled and disabled blocks will not be placed as

Part of structures and will not load as part of entities such as falling blocks or held by endermen. If a disabled block is still encountered in a world, a player will be unable to interact with it. Disabled items are hidden from the creative inventory and will not be recognized by commands

That create new items like the give command. Recipes and loot tables cannot create disabled items. If a player somehow did get a disabled item, they won’t be able to use it for interactions or attacks. Disabled entities cannot spawn or load.

Their ids are not recognized by commands that can summon new entities, and their spawn egg items are also disabled. The jar file for the game now also contains two built-in datapacks for experimental features: bundles and update_1_20. Some news for technical blocks and items: you can now get them from the creative inventory

By switching on the new Operator Items Tab option in controls settings. There is also a change to barrier blocks and structure voids which no longer produce particles when broken. Let’s move on to recipes. Which crafting book tab a recipe appears in can now be controlled by recipe data through a field called category.

For regular crafting, the available categories are building, redstone, equipment and misc, where misc is the default. For smelting and similar item cooking recipes, the available categories are food, blocks and misc, again with misc being the default. Some recipe books might collapse categories into fewer tabs and the exact mapping might

Change in the future. In entity data changes, allays will no longer dance if you set their NoAI field to true. You can now set the AngryAt UUID for endermen by modifying their data. And death times of above 20 no longer produce indefinitely corrupted mobs.

Vexes are no longer a humanoid model, so they can no longer visually wear player heads. Speaking of player heads, they now have a new note_block_sound field. When this is set and the head is placed above a note block, the note block will play that sound asset when triggered.

When set up this way, the note block instrument state also switches to a new custom value. For predicates, new sub-predicates have been added for a number of entity types that have variants, just like the frog and cat ones that were already available. This includes axolotls, foxes, mooshrooms, rabbits, horses, llamas, villagers, parrots

And tropical fish… but also non-mob entities: boats and paintings. In tag news, the non_flammable_wood block tag has been removed and two new block tags have been added: all_signs and invalid_spawn_inside. The overworld_natural_logs item tag has also been removed and two new item tags have been added: creeper_igniters and fence_gates.

There are also some added tags inside the update_1_20 built-in datapack. Four block tags: all_hanging_signs, ceiling_hanging_signs, wall_hanging_signs and bamboo_blocks. And three item tags: bamboo_blocks, hanging_signs and bookshelf_books. In resource pack news, the resource pack version is now 12. This skips a few versions from 1.19.2, because the pack versions will now be increased every

Time a breaking format change is made rather than only once per snapshot cycle. In this version, old auto-upgrade functionality has been removed where the game would automatically try to upgrade resource packs older than version 3. Changes for this pack version include an entirely new format for the vex textures and changes

To the creative inventory tabs.png file to where tabs are now 26 pixels wide instead of 28. The default player skins have moved into a player subfolder, which in turn has wide and slim subfolders which contains variants of all of the new default skins.

This means all the skins exists in both wide and narrow versions now. The checkmark.png texture has moved out of the realms namespace and into the minecraft one, and all the realms language strings are now in the minecraft language file – the realms one no longer exists.

Resource packs can now have atlas configuration files that control which images are included as parts of texture atlases. Those are found in a new atlases folder, and each file is a json object with entries for configuring various rendered types. And the programmer art resource pack is no longer internally called programer art.

Let’s move on to servers – custom world datapacks can now be used on servers using a few new fields in server.properties. initial-enabled-packs lists which datapacks should be enabled at world creation, and initial-disabled-packs lists ones that should be disabled. Any datapacks that have feature flag requirements need to be in the initial-enabled-packs list

To be enabled, and any datapacks discovered after world creation will be disabled if they require features that are not enabled for the loaded world. For modding, first a note that this release is the first one under a new release strategy

For the game, where larger changes will be published more regularly throughout the year in minor versions. This means that if you want to keep a mod up to date with released versions, you’ll need to upgrade your mod to updated code more often but through somewhat smaller amounts of changes.

The network protocol has been changed to add support for player entities being added to the world without first being added to the tab list, along with some changes to the secure chat protocol. The linear algebra types for floats have been switched to use the Java OpenGL Math Library or JOML.

Let’s wrap up with news for custom worlds. There is no longer a vanilla world generation reference pack – instead the vanilla world generation files are now shipped as part of the vanilla data pack inside the jar file of the game.

Only a few changes to the actual formats in this version – template pools no longer have an extra name field, and the format for specifying custom sounds for biomes has changed. When using custom sounds, they are now specified as in-line objects with a sound_id field.

And that’s all for the technical changes in Minecraft 1.19.3. My name is slicedlime, thank you for watching. I’ll see you next time.