API status

Everything a mod can change today, area by area, and what’s still on the way. API version 3.

built works in the port nowpartial player-only, or only through a general routeplanned designed, not built yet

Ways to mod

JFG-Studio writes the data files and the Lua for you; you only touch them by hand for what Studio doesn’t cover yet.

Details: Weapons.

Capability	How	Status
Damage	`jfg.weapon(n, {damage=})`, 0–255, any of the 15 stock weapons by slot	built
Fire rate	`delay`: frames between shots (0–255)	built
Projectile and throw speed	`speed` (0.1–2000)	built
Projectile lifetime (range)	`lifetime` (1–255)	built
Spread (accuracy)	`spread_x`, `spread_y` (0–8192; 65536 is a full turn)	built
Throw timing	`throw_delay`: frames from press to release (1–127)	built
Read a weapon’s values	`jfg.weapon_stats(n)`	built
Weapon values without code	Studio’s Weapons window (`weapons.json`)	built
Laser bolt size, plasma charge speed, mine limit, pistol rapid-fire heat	Only in the player’s F9 Weapons tab	partial
Gun and projectile models and textures	Replace their model or texture entries; changes them everywhere, not per weapon	partial
New weapons in extra slots	`jfg_weapon_register`: virtual slots 16 and up that borrow a stock weapon’s firing, reticle and HUD	planned
Gun model per hero, HUD icon	Needs the gun-model choice and the HUD strip draw named in the decomp	planned
Give, take and ammo	`jfg_weapon_give / has / get_ammo / set_ammo / current`	planned
Weapon events	`jfg_on_weapon_fire`, `jfg_on_weapon_select`, `jfg_on_projectile_hit`	planned

Capability	How	Status
Replace game data	A whole asset, or one entry of a set: level header, track, model, texture, object list	built
Add levels, tracks, models, textures, object definitions	`"append"`: numbered at start-up, kept in `bin/mod_ids.json` so saves stay valid	built
Link entries by name	`"fixups"` write the real numbers once known, even another mod’s	built
Edit a stock level without replacing it	`"patches"`: byte edits, and object-list set, delete and append; several mods can patch one level	built
Build from the player’s own data	`"copyOf"` plus byte edits, so a pack carries no game data	built
Level look: fog, sky, clear colour, music, ambient loops	The level header (Studio’s Level window); `jfg.fog()` at run time	built
Doors and game flags	`jfg.unlock_door`, `jfg.door_locked`, `jfg.flag`, `jfg.set_flag`	built
Warp to a level	`jfg.warp(level, start_point)`	built
Water, lava, pits, invisible walls	Surfaces from Blender material names; Studio’s Water tool	built
Moving platforms, jetpack pads, Galaxian flight paths	Wait on the decomp naming their data	planned

Capability	How	Status
Place any stock object	Object lists (appended or patched)	built
New enemy types (reskins)	Studio kinds: a stock enemy with new textures and size, its own object id	built
Borrow animations for a new model	`"animRows"`	built
Squad size	The squadron’s Size field, shared by its members	built
Spawn at run time	`jfg.spawn(id, x, y, z, {params})`, 64 per level	built
Hide or change how an object draws	C event `jfg_on_object_draw`	built
New models (meshes)	Appended model entries work; Studio has no model importer yet	partial
Objects with their own behaviour	Lua object kinds and handles; bosses and talkers as kinds	planned

Capability	How	Status
New planets on the map	`jfg_world.json`: on the game’s galaxy or the pack’s own (L and R switch)	built
Routes	From a stock map point or another planet; clashes between mods move to a free direction	built
Unlock rules	start, stock, script, entered, completed, discovered; kept per save file	built
Open and complete from code	Lua `jfg.unlock_planet` and friends; C `jfg_world_`, `jfg_galaxy_`	built
Map events	`jfg_on_map_open`, `jfg_on_galaxy_change`, `jfg_on_planet_select`	built
Planet regions	`jfg_assets.json` `"regions"`: the stats screen on leaving a planet, its area title, continues	built
Fly your ship between planets	A design scenario; not scheduled	planned

Capability	How	Status
Run code each level and tick	`jfg.on("level", fn)`, `jfg.on("tick", fn)`	built
Triggers without code	Studio’s Triggers window	built
Player position, buttons	`jfg.player()`, `jfg.pressed(name)`, `jfg.held(name)`	built
On-screen messages and talkers	`jfg.message`; Studio’s talk trigger and lines action	built
Logging	`jfg.log`, `print`; C `recomp_printf`	built
Hot reload of scripts	Reload Lua without restarting	planned
Pause screen	Hooks for the pause menu; waiting on the decomp	planned

Capability	How	Status
Custom level music	`jfg_music.json`: OGG per level with loop points	built
Switch music from a script	`jfg.music(name)`, `jfg.music_stop()`	built
Replace or mute a sound effect	`jfg_on_sound_play`	built
New sound effects	Only the game’s own sounds can be played	planned
Blood and gore	`jfg_on_blood_spurt`, `jfg_on_blood_hit`, `jfg_on_severed_limb_tick`	built
Screen hit flash	`jfg_on_screen_flash`	built

Capability	How	Status
Every tick, frame-rate safe	`jfg_on_game_tick(frames)`, `jfg_get_tick_scale()`	built
Level changes	`jfg_on_level_change`, `jfg_get_level`	built
Boss fights and Floyd	`jfg_on_boss_fight_control`, `jfg_on_sidekick_tick`	built
Change any game function	`RECOMP_HOOK`, `RECOMP_PATCH` (a few overlay functions can’t be hooked)	built
Share code between mods	Library mods: exports, events, dependencies	built
Draw from a mod	Display lists, vertices and textures in the mod’s own memory	built
Co-op in the story	A design scenario; not scheduled	planned

Capability	How	Status
HD texture packs	RT64 packs as mods or folders; Options or F6	built
Texture dumping for upscalers	Game textures in `texture_dump/`, each mod’s own in `texture_dump/<mod id>/`	built
New textures in a pack	Appended or replaced texture entries	built
Studio reusing stock textures	An image identical to a game texture could use the game’s own; the importer can, Studio leaves it off	partial
Translations	Locale files: menus, subtitles, hints; `jfg_get_language`, `jfg_on_language_change`	built