Java Edition 21w10a

21w10a is the thirteenth snapshot for Java Edition 1.17, released on March 10, 2021, which adds lush caves and new deepslate variants.

Blocks

 * Cracked Deepslate Bricks
 * A cracked variation of deepslate bricks.
 * Obtained by smelting deepslate bricks.


 * Cracked Deepslate Tiles
 * A cracked variation of deepslate tiles.
 * Obtained by smelting deepslate tiles.


 * Deepslate Ore
 * Added deepslate ore variants for copper, emerald and coal ore.
 * Do not generate by default; they only have been added for use by creators of maps and data packs.
 * Like other deepslate ores, they can be used in blasting and smelting recipes like normal ores.
 * Again, like other deepslate ores, they will unlock these recipes in the recipe book.


 * Infested Deepslate
 * An infested variant of deepslate.

World generation

 * Azalea Tree
 * Generate above lush caves, either on surface or underground.
 * Consist of azalea leaves (both variants), oak logs and rooted dirt.


 * Lush Caves biome
 * Currently the biome is only accessible in single-biome worlds.
 * Adaptive to the environment: every type of cave generation can be a lush cave.
 * Moss covers the floors and ceilings, along with moss carpets and grass on the floors.
 * Spore Blossoms grow from the ceiling and drip particles.
 * Contains clay pools where dripleaf plants grow out of them.
 * Clay pools will sometimes generate water sources over air, and the water is suspended and does not flow. This has yet to be fixed.
 * Contains azalea bushes (both variants).
 * Cave vines with glow berries grow from the ceiling and light up the caves.

General

 * Shaders
 * Are now included for all supported render states.
 * Any shader except for the blit shader can also be replaced in resource packs.
 * For now replacing these shaders is not officially supported and the way it works may change in the future.
 * Current rendering engine uses a system similar to the post processing shader pipeline. There are some differences between both system that cater to the slightly different requirements.


 * Tags
 * Added the block and item tags.
 * Contain both the normal and deepslate ores of each ore type.
 * Added the block tag.
 * Contains the  block tag, clay, and moss block.

Blocks

 * Deepslate diamond ore, deepslate gold ore, deepslate iron ore, deepslate lapis lazuli ore, deepslate redstone ore, coal ore, diamond ore, iron ore, gold ore
 * The textures of these ores have been changed.
 * Iron ore and deepslate iron ore no longer have streaks, better matching the appearance of other ores.
 * Diamond ore closer resembles deepslate diamond ore.


 * Cobbled Deepslate
 * The texture has been changed.
 * Can now be smelted back into deepslate.


 * Deepslate
 * Both the top and sides textures have been changed.
 * Deepslate can now be placed along any axis.
 * Textures in caves now generate with a random rotation.


 * Deepslate Bricks and Deepslate Tiles
 * Can now be crafted.

Lightning Rod


 * Changelog states they can now be waterlogged, though this is not the case.

Items

 * Spyglass
 * The item model has been changed back to a dedicated texture.
 * Similar to tridents, the spyglass still uses a 3d model in the hand.
 * The texture is different from the original item texture.

Mobs

 * Slime
 * The maximum size that slimes can be summoned with is now 128.

World generation

 * Crack carvers
 * Now are much less common.


 * Fossils
 * The fossils in the deepest part of the underground generate with Deepslate Diamond Ore instead of Coal Ore.


 * Ore distribution
 * Now generates more emerald ore in mountains.
 * Now generates more lapis lazuli ore.
 * Now generates less copper ore, gold ore, and redstone ore.
 * Now generates smaller diamond ore blobs, but slightly more frequent (less diamond ore overall though).
 * Now generates less iron ore, and it generates lower down.
 * The deepest iron generation range: previously Y = -64 to -8, now Y = -64 to -32.
 * The middle iron generation range: previously Y = -16 to 80(most at 32), now Y = -24 to 56(most at 16).
 * Reduced air exposure for coal ore.

Command format

 * The give command can only give up to 100 stacks of items at a time (e.g. 6400 stone or 100 iron swords)
 * The give command can only give up to 100 stacks of items at a time (e.g. 6400 stone or 100 iron swords)


 * Can no longer set a player's spawnpoint to areas that are out of the world.
 * Can no longer set a player's spawnpoint to areas that are out of the world.

Gameplay

 * Glowing is now based on the outline of all layers on an entity, not just the base layer.
 * Glowing is now based on the outline of all layers on an entity, not just the base layer.

General

 * Game library updates
 * Rendering is now using OpenGL 3.2 core profile.
 * All fixed function rendering has been replaced with shader based rendering.


 * Splashes
 * Changed the splash "OpenGL 2.1 (if supported)!" to "Now on OpenGL 3.2 core profile!"


 * Subtitles
 * Glow item frames have their own subtitles, no longer using the same subtitles as normal item frames.


 * Tags
 * Removed moss block, the  block tag, grass, tall grass, moss carpet, small dripleaf, big dripleaf, big dripleaf stem, and vines from the  block tag.
 * Removed the block tag.

Video
Video made by slicedlime: