Utilities

Utilities

Registration – util.RegistryUtil

RegistryUtil.registerWithItem(BLOCKS, BLOCK_REGISTRAR, ITEMS, ITEM_REGISTRAR, MyMod.identifier("oak_table"), () -> new TableBlock(props));
RegistryUtil.registerWithoutItem(BLOCKS, BLOCK_REGISTRAR, MyMod.identifier("wall_banner"), () -> new CompletionistWallBannerBlock(props, BANNER));
RegistryUtil.registerItem(ITEMS, ITEM_REGISTRAR, MyMod.identifier("knife"), () -> new SwordItem(...));

Shapes – util.ShapeUtil

VoxelShape east = ShapeUtil.rotateShape(Direction.NORTH, Direction.EAST, northShape);
ShapeUtil.isFaceFull(level, pos);   ShapeUtil.isSolid(level, pos);   ShapeUtil.isFullAndSolid(level, pos);
ShapeUtil.getRelativeHitCoordinatesForBlockFace(hit, facing, blockedFaces); // x/y 0..1 on the clicked face

Everything else – util.LibUtil

tracking(level, pos) (players that see a chunk), fillBucket / emptyBucket, popResourceFromFace, putBlockPos / putBlockPoses / readBlockPoses (NBT), isFire(damageSource), isDamageType(...), convertStackAfterFinishUsing(...) (bowls/bottles after eating), getInPercent, isIndexInRange.

Dyeing – util.DyeHelper

// in useItemOn, with a DyeItem in hand – recolours the block, consumes the dye, plays sound + dye splash
return DyeHelper.dye(stack, dye.getDyeColor(), state, COLOR, level, pos, player);

Items on blocks – render.DisplayItemRenderer

DisplayItemRenderer.renderFlat(stack, poseStack, buffers, light, overlay, level, x, y, z, yaw, scale, seed);    // lying down
DisplayItemRenderer.renderUpright(stack, poseStack, buffers, light, overlay, level, x, y, z, yaw, scale, seed); // standing

Also here

Class	Use
util.ImplementedInventory	Container from a NonNullList in two lines
util.StreamCodecUtil	stream codec helpers
render.ClientUtil	light level at a position, GUI item rendering
text.TextEditableBlockEntity + SetTextPacket	blocks with editable text (signs, bowls): implement the interface, send SetTextPacket.sendToServer(...)
client.render.FluidBoxRenderer	renderWaterBox(...): biome tinted water inside a block entity (tubs, tanks, basins)
fabric.datagen.ModelGenHelper (Fabric module)	datagen shortcuts: blockId, variantIds, slabFromTexture …
advancement.SimplePlayerTrigger	"player did X" advancement trigger: register one per event, call trigger(player)