Create a weather

Principle

Adding a weather involves four steps:

• Add the text messages: the messages displayed on activation, end, and each turn.
• Create the effect class: the mechanical behavior of the weather (type multipliers, per-turn damage, etc.).
• Register the weather in the handler: link the weather symbol to the messages.
• Trigger it: allow its activation via a move or an effect.

Adding text messages

Weather messages are stored in file 100018 in Pokémon Studio. Up to three messages need to be added:

• An activation message (when the weather appears) -- e.g., "It started to rain!"
• An end message (when the weather fades) -- e.g., "The rain stopped."
• A turn message (displayed at the end of each turn, optional) -- e.g., "The sandstorm rages."

Note the line numbers of these messages in Pokémon Studio, they will be needed for registration in the handler.

Existing weathers use these line numbers in file 18:

Weather	Activation	End	Turn
Rain	88	93	--
Sunny	87	92	--
Sandstorm	89	94	98
Hail	90	95	99
Fog	91	96	--
Snow	287	288	289

Creating the effect class

Weathers inherit from Battle::Effects::Weather and are placed in the 5 Battle/06 Effects/06 Weather Effects/ folder.

Here is the minimum required for a working weather:

module Battle
  module Effects
    class Weather
      class VoidWeather < Weather
        def on_end_turn_event(logic, scene, battlers)
          if $env.decrease_weather_duration
            scene.display_message_and_wait(parse_text(id_file, id_text))
            logic.weather_change_handler.weather_change(:none, 0)
          end
        end
      end
      register(:void_weather, VoidWeather)
    end
  end
end

The strict minimum is:

• on_end_turn_event: manages the weather's duration. $env.decrease_weather_duration counts down turns and the weather expires when it returns true. Without this method, the weather lasts indefinitely.
• register(:void_weather, VoidWeather): ties the symbol to the weather via the factory pattern. Without this call, the weather cannot be instantiated.

Between these two elements, you add the desired behavior by overriding EffectBase hooks. For example, Rain overrides mod1_multiplier to boost Water moves (x1.5) and weaken Fire moves (x0.5). Existing weathers in 5 Battle/06 Effects/06 Weather Effects/ show the different possibilities.

Available hooks

Weathers can override any hook from EffectBase. The full list can be found in 5 Battle/06 Effects/100 EffectBase.rb.

Registering the weather in the handler

The WeatherChangeHandler manages weather application and messages. Two constants need to be updated.

Adding the symbol to WEATHER_NAMES

The WEATHER_NAMES array in PFM::Environment lists all known weather symbols:

module PFM
  class Environment
    WEATHER_NAMES << :void_weather
  end
end

Adding the activation message to WEATHER_SYM_TO_MSG

The WEATHER_SYM_TO_MSG hash contains the mapping between weather symbols and message line numbers. It is not frozen, so you can simply add entries:

module Battle
  module Logic
    class WeatherChangeHandler
      WEATHER_SYM_TO_MSG[:void_terrain] = 400
      WEATHER_SYM_TO_MSG[:none][:void_terrain] = 401
    end
  end
end

The hash structure is as follows:

• WEATHER_SYM_TO_MSG[:void_terrain] = 400: the activation message (line 400 from text file 60).
• WEATHER_SYM_TO_MSG[:none][:void_terrain] = 401: the end message (line 401), displayed when the terrain changes to :none.

Triggering the weather via a move

To create a move that invokes the weather:

Configure the move in Pokémon Studio

Create the move in Pokémon Studio with these properties:

• Procedure: s_weather
• Category: Status
• PP: 5 (typical)
• Target: All Pokemon

Register the move in WeatherMove

The WEATHER_MOVES hash maps a move's db_symbol to the weather symbol. Simply add an entry:

module Battle
  class Move
    class WeatherMove
      WEATHER_MOVES[:void_weather] = :void_weather
    end
  end
end

Register the duration extension item (optional)

If an item extends the weather duration (from 5 to 8 turns), add it to WEATHER_ITEMS:

module Battle
  class Move
    class WeatherMove
      WEATHER_ITEMS[:void_weather] = :void_rock
    end
  end
end

Triggering the weather via an effect

The example below shows an ability effect, but the same methods apply for an item or any other effect that triggers a weather:

module Battle
  module Effects
    class Ability
      class VoidStream < Drizzle
        private

        def weather
          return :void_weather
        end

        def item_db_symbol
          return :void_rock
        end
      end
      register(:void_stream, VoidStream)
    end
  end
end

The effect inherits from Drizzle (or any existing weather effect) and only overrides weather (the weather symbol) and item_db_symbol (the duration extension item). The system automatically handles the duration (5 turns, or 8 with the item).

Reference examples can be found in 050 Weather Setting Abilitites.rb.

Adding a weather query method

To be able to check the active weather in code (e.g., logic.weather_effect.void_weather?), you need to add a query method to the base class:

module Battle
  module Effects
    class Weather
      def void_weather?
        return @db_symbol == :void_weather
      end
    end
  end
end

File summary

File	Action
Studio -> Battle System (file 100018)	Add activation, end and turn messages
my-project/scripts/001 Weather.rb	Add symbol to WEATHER_NAMES
my-project/scripts/002 WeatherChangeHandler.rb	Add entry to WEATHER_SYM_TO_MSG
my-project/scripts/003 WeatherEffect.rb	Create the weather effect class
my-project/scripts/004 WeatherMove.rb	Add to WEATHER_MOVES and WEATHER_ITEMS (if move)
my-project/scripts/005 Ability.rb	Create the effect (if effect)
Studio -> Moves	Create the move with s_weather procedure (if move)

Conclusion

• First add the messages in Studio (file 100018), as they are needed for the handler.
• Create the effect class by inheriting from Weather with at minimum on_end_turn_event and register.
• Add the symbol to WEATHER_NAMES and the entry to WEATHER_SYM_TO_MSG to link the messages.
• Add the entry to WEATHER_MOVES for moves, or inherit from Drizzle for effects.
• Existing weathers in 5 Battle/06 Effects/06 Weather Effects/ serve as reference for possible behaviors.