Fundamentum

A library: on its own it adds no items. Install it with a content mod such as Ostentum or Flora Ferox to get them.

Terraria-style wings, mounts, grappling hooks, summons and real cord whips for Minecraft, plus elemental reactions, blood-moon nights and fractal skies. Fundamentum is the engine: it adds the slots, keys and systems, and content mods add the wings, hooks, whips and charms that use them.

Everything is set up through datapacks, so pack makers can add and retune content without code, and gear from different mods stacks instead of each mod rolling its own.

What players get (through content mods)

• Wings in their own Curios slot, with a cosmetic slot beside it. Hold jump to fly Terraria-style, then glide. No fall damage while flying or gliding.
• Mounts. Put a mount item in the mount slot and press V to call the creature and ride it. Press V again, or get off, and it goes away.
• Grappling hooks. Put a hook in the hook slot and press H to fire it. It latches onto a block and pulls you there. Jump to let go.
• Summons. Charms in the summon slot call minions that follow you and fight what you fight. They never hurt you or each other.
• Whips with a real cord. The whole cord hits as it swings, the tip hits hardest, and a crack at the tip is a crit. Whips take Sharpness, Smite, Bane of Arthropods and Fire Aspect.
• Cosmetic armour slots. Wear one set for looks and another for protection.
• 3D arrows in place of the flat vanilla ones.
• Special moons and night events. Blood-moon style nights that tint the sky and fog, with their own mobs, effects, loot and messages, plus events like raids or feasts.
• Fractal skies. A moon, event or dimension can swap the sky for a slowly zooming Mandelbrot, Julia or burning-ship fractal, with an optional melting-vision effect. Both can be turned off in the client config.
• The Psychedelic Moon, a rare rainbow-fractal night. It's off unless you turn it on in the config.
• Elements. Hits can be fire, ice, water, electric, earth, air, poison, holy, shadow or arcane. They leave auras, and the wrong element on an aura sets off a reaction. Creatures and gear can resist elements, be weak to them or be immune. A datapack can add a whole new element, with its own variants, auras and reactions, with no code.
• Portal crafting. Some items change when you throw them through a Nether or End portal.
• Use sickness for potions and other consumables, like Terraria's potion sickness.
• Item tooltips for whips and hooks, and description lines for any item that has them.
• Max health above 1,024, for big bosses.

What it gives mod and pack makers

• Data tables that merge across datapacks and sync to clients, plus stat patches for tiers and upgrades.
• Shared combat attributes (crit chance and damage, ranged damage, fire rate, reload speed, ammo conservation, armour pierce, blast radius, projectile speed, spread and more), so gear from different mods stacks.
• Creature types and damage rules, e.g. holy weapons hit undead harder.
• Damage classes (melee, ranger, marksman, mage) and shared damage types any mod can deal.
• Datapack formats for wings, mounts, hooks, summons, whips, moons, night events, fractal skies, use sickness, new elements, element reactions, creature damage and portal crafting recipes.
• Player poses and animation clips, first-person arms, and left-click triggers for charge or hold weapons.
• Commands for testing: /fundamentum moon starts any moon or night event, /fundamentum element lists elements and shows auras and reactions, /fundamentum tps shows lag per dimension, and /fundamentum showcase builds a gallery of every mob from a mod.

Requires Curios. Open source under the GNU LGPL-3.0-or-later, so any mod may depend on it.

Wiki: datapack formats, KubeJS, the API and commands are documented at oculifelis.github.io/mod-wiki.

Credits

The whip cord code adapts Better Whips by my2167592261-cell, under the MIT License; none of Better Whips' models, textures or sounds are used.

Licence: open source under the GNU LGPL-3.0-or-later from 1.25.8, so any mod may depend on it under any licence.

Mods that use Fundamentum

• Ostentum: weapons, relics and summons built on Fundamentum's wings, mounts, hooks, summons and whips.
• Flora Ferox: herb monsters, seed guns, whips, grappling hooks and wings built on Fundamentum.