Biomes Overview
ReInDev defines its biomes in Biomes.java, where each entry is registered with a numeric ID, a height/density modifier, climate flags, and one or more biome groups. The group an entry belongs to determines which dimension it generates in and which world generator places it. The BIOME_LIST array holds 53 entries, but four are tiny Nether "dungeon" pockets and a handful are non-generating legacy placeholders, leaving 49 biomes that actually appear in worlds.
How biomes are organized
Placement is controlled by the BiomeGroup enum, which pairs each group with a dimension index and a generator type:
| Group | Dimension | Role |
|---|---|---|
| OVERWORLD | 0 | Normal surface terrain, temperature/rainfall driven |
| SKYLANDS | 0 | Omnipresent floating-island layer above the Overworld |
| LEGACY | 0 | Old-style worldgen for legacy/converted saves |
| SURFACE / MIDDLE / LOWER_NETHER | -1 | Three stacked vertical bands of the Nether |
| NETHER_DUNGEON | -1 | Enclosed Nether structure pockets |
| NO_GENERATION | 0 | Placeholders (Seasonal Forest, Ice Desert, Hell, Sky) kept for IDs only |
Climate is set per-biome with two flags. setEnableSnow() makes a biome cold (snow falls, water freezes, no lightning), and setDisableRain() turns off precipitation entirely. Every Nether and sky biome calls setDisableRain(); cold biomes additionally call setEnableSnow().
Overworld biomes
The surface dimension hosts the largest share of biomes. Standard land biomes — Plains, Forest, Savanna, Shrubland, Flower Forest, Rainforest, Mountain — share the default grass-over-dirt-over-stone soil and full rain. Distinctive members:
- Mushland — mycelium top over stone; spawns Mooshroom, Brown Mooshroom, and a rare Glowing Mooshroom.
- Swamp — heavily lowered density (-35.7) producing wide, flat, water-logged terrain.
- Cacti Desert / Dry Desert / Desert — sand over sandstone, rain disabled.
- Wasteland and Quickland — eroded badland-style terrain using Limestone fill and Hardened Clay as the ore-rock; both disable rain, and Wasteland runs dry (air fluid).
- Oceans & coasts — Ocean, Coral Ocean, Coast, Rocky Coast, Beach, Rocky Beach, Frozen Beach, Islands, and Lake all sit at low height modifiers; the "ocean/coast" variants are flagged
countsAsOcean. - Cold biomes — Tundra, Snowy Taiga, Frostland, and Frozen Beach enable snow; Frostland and Snowy Taiga use ice as their fluid and snow-block tops, and spawn Foxes (and Wolves in Snowy Taiga).
Sky (Skylands) biomes
Four biomes form the omnipresent floating-island layer, all sharing an extreme negative density (-2000) and a raised height so terrain appears as scattered islands. Rain is disabled for all of them.
- Cherry Groves — grows cherry trees and cherry leaf piles.
- Grassy Fields — open grass plateaus with tall grass.
- Stony Mountains — bare stone-and-limestone peaks.
- Icy Peaks — packed-ice and snow-block summits.
The base Sky biome spawns sky-exclusive mobs including the Wyvern, Moobloom, and Moolip.
Nether biomes
The Nether is split into three vertical bands (Surface, Middle, Lower) populated by a 64x64 lookup grid, so a single descent passes through multiple biomes. Each replaces the default soil with thematic blocks and a custom fluid (lava, acid, or sanguis). Highlights:
- The Wastes — Ridrock terrain with brimstone spikes and stalactites; spawns Zombie Pigmen.
- Crimson / Azure / Ebony Forests — basalt nylium variants (crimson, azure, ebony) with their own foliage; Ebony uses an acid fluid.
- Basalt Delta — basalt and crimson-nylium fields with magma, brimstone stalagmites, and craggy spikes.
- Soul Sand Valley — soul sand/sandstone over ridrock with jet clusters; spawns Wither Skeletons and Skeletons.
- Sulphurous Springs — brimstone and mineral sand with an acid fluid and the occasional Blaze.
- Crystal Caverns — opal-laced ridrock and mineral sandstone, a Lower-Nether band.
- The Crag, Slatewastes, Ashflats, Slagheaps — slate, basalt, ash, slag, and tar wastes; Slatewastes spawns Blood Wyverns.
- Great Cysts — fleshy, organic terrain (Flesh, Necrotic Flesh, blood magma) over a sanguis fluid.
- Morevil Kingdom — a Middle-Nether mushroom realm with mycelial netherrack, portabella, and Mooshevil mobs.
Four enclosed dungeon biomes — Magma, Kottamagma, Wither, and Rainbow — belong to the NETHER_DUNGEON group and generate as self-contained structures rather than open terrain.
Legacy and placeholder biomes
The LEGACY group (Plains, Forest, Savanna, Shrubland, Desert, Swamp, Flower Forest, Rainforest, Mushland, Taiga, Tundra) reproduces the older temperature/rainfall biome table via getBiome() for converted worlds. Seasonal Forest, Ice Desert, Hell, and Sky are kept in NO_GENERATION purely to preserve their IDs and never spawn naturally.