Fx Control Mod Wiki

Fx Control is a server-side utility mod designed to give modpack authors absolute control over player experiences. By utilizing a rule-based system defined in JSON files, you can automate the application of potion effects, set players on fire, or restrict block interactions based on a vast array of conditions such as biomes, dimensions, time of day, and even game stages.

In versions 1.18.2 and 1.19.2, Fx Control operates as a standalone mod. However, starting with Minecraft, its functionality has been merged into the In Control! mod. The configuration files are typically located in the config/fxcontrol/ directory (or config/rfcontrol/ in older versions).

The mod's behavior is defined through five primary JSON files. Each file handles a specific type of event or state.

Rule Structure

Every rule within these files consists of three main parts:

1. Conditions: Tests that must be true for the rule to execute (e.g., "Is the player in the Nether?").
2. Actions: The results of the rule (e.g., "Apply Slowness II").
3. Result: Specifically for event files, this determines if the action is allowed or denied.

Conditions are the "if" part of the rule. Multiple conditions in a single rule act as an "AND" operation.

Environmental Conditions

• dimension: A list of dimension IDs (e.g., ["minecraft:overworld", "minecraft:the_nether"]).
• biome: A list of biome registry names (e.g., ["minecraft:plains"]).
• biometags (1.19+): Checks for specific biome tags (e.g., "#minecraft:is_forest").
• time: A range of daytime values (0-24000).
• minlight / maxlight: Checks the light level at the player's position.
• minheight / maxheight: Checks the player's Y-coordinate.
• block: The block the player is currently standing on.

Player & Item Conditions

• helditem: Checks the item in the player's main hand or offhand.
• gamestage: Integration with the Game Stages mod; checks if a player has a specific stage.
• baubles: Integration with Baubles; checks for specific equipped items.
• seasons: Integration with Serene Seasons; checks the current season.

Structure Conditions (1.19+)

• structure: Checks if the player is inside a specific structure (e.g., "minecraft:fortress").
• hasstructure: A boolean check to see if any structure exists at the location.
• structuretags: Checks for structure tags.

Actions define what happens when all conditions are met. Results are used in event-based files to permit or block player actions.

Effect Actions (effects.json)

Event Results

In breakevents.json, placeevents.json, and click files, the result field is mandatory:

• allow: The action is permitted even if vanilla would normally block it.
• deny: The action is blocked (e.g., the block will not break or be placed).
• default: Follows standard vanilla behavior but applies any additional actions defined.

Fx Control is built to work seamlessly with several popular mods to provide deeper integration for modpack creators:

• Game Stages: Restrict effects or interactions until a player reaches a certain progression milestone.
• Serene Seasons: Apply seasonal hazards, such as slowness during heavy snow in winter.
• Baubles / Curios: Trigger effects based on what accessories the player is wearing.
• The Lost Cities: Create rules that only apply when a player is inside specific building types or city sectors.
• EnigmaScript: Allows for complex scripting within the rule system.

The mod provides administrative commands to help test and reload configurations without restarting the game.

• /fxcontrol reload: Reloads all JSON configuration files from the disk. This is essential for testing changes to effects.json or event files.
• /fxcontrol debug: Toggles debug mode. When active, the mod will output detailed information to the server log whenever a rule is evaluated, helping to identify why a specific effect is or isn't triggering.

Poison in the Nether (effects.json)

This rule applies Poison I to any player in the Nether who is not wearing a full set of gold armor (assuming gold armor is checked via other conditions or NBT).

[
 {
 "dimension": "minecraft:the_nether",
 "potion": "minecraft:poison",
 "amplifier": 0,
 "duration": 100
 }
]

Prevent Breaking Diamond Ore (breakevents.json)

This rule prevents players from breaking Diamond Ore unless they have reached the "expert" game stage.

[
 {
 "block": "minecraft:diamond_ore",
 "gamestage": "expert",
 "result": "allow"
 },
 {
 "block": "minecraft:diamond_ore",
 "result": "deny",
 "message": "You do not have the knowledge to mine this!"
 }
]