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Tomasz Wegrzanowski
Tomasz Wegrzanowski

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Open Source Adventures: Episode 56: Extending BATTLETECH Weapon data exporter

I wanted to add some functionality to the app, but for that I need a bit more data. So here are the changes I needed to do to the data exporter:

  • filter out Flamers and Infernos
  • split name field (like SRM6+ (+2 Dmg)) into baseName (like SRM6+) and bonus (+2 Dmg)
  • added category
  • added baseStabDamage

I might need to do some more changes in the future, for now this will do.

One thing to note is that bonus field is purely visual, and all the bonus information is included in the data already.

Generated JSON example

{
  "baseName": "Gauss Rifle+",
  "bonus": "-2 Tons",
  "tonnage": 13,
  "heat": 5,
  "shots": 1,
  "baseDamage": 75,
  "ammoTonnagePerShot": 0.125,
  "minRange": 180,
  "maxRange": 660,
  "indirectFire": false,
  "baseStabDamage": 40,
  "category": "Ballistic"
}
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Script

The changes from previous version are fairly trivial.

#!/usr/bin/env ruby

require "json"
require "memoist"
require "pathname"
require "pry"

class String
  def camelize
    gsub(/_([a-z])/) { $1.upcase }
  end
end

class AmmoBox
  extend Memoist
  attr_reader :data, :path

  def initialize(path)
    @path = path
    @data = JSON.parse(path.read)
  end

  memoize def id
    @data["AmmoID"].sub(/\AAmmunition_/, "")
  end

  def tonnage
    @data["Tonnage"]
  end

  def capacity
    @data["Capacity"]
  end
end

class Weapon
  extend Memoist
  attr_reader :game, :data, :path

  def initialize(game, path)
    @game = game
    @path = path
    @data = JSON.parse(path.read)
  end

  memoize def name
    if has_bonus?
      "#{base_name} (#{bonus})"
    else
      base_name
    end
  end

  memoize def has_bonus?
    [bonus_a, bonus_b].any?
  end

  memoize def bonus
    [bonus_a, bonus_b].compact.join(", ")
  end

  memoize def base_name
    [
      data["Description"]["Name"],
      data["Description"]["UIName"],
    ].compact.last.gsub(" +", "+")
  end

  memoize def bonus_a
    data["BonusValueA"] == "" ? nil : data["BonusValueA"].gsub(/[a-z]\K\./, "").gsub(/[\+\-]\K /, "")
  end

  memoize def bonus_b
    data["BonusValueB"] == "" ? nil : data["BonusValueB"].gsub(/[a-z]\K\./, "").gsub(/[\+\-]\K /, "")
  end

  def category
    @data["Category"]
  end

  def subtype
    @data["WeaponSubType"]
  end

  def tonnage
    @data["Tonnage"]
  end

  def damage
    shots * base_damage
  end

  def base_damage
    @data["Damage"]
  end

  def shots
    @data["ShotsWhenFired"]
  end

  def heat
    @data["HeatGenerated"]
  end

  def ammo_per_shot
    @data["ShotsWhenFired"] * data["ProjectilesPerShot"]
  end

  def heat_tonnage
    heat / 3.0
  end

  # 10 rounds of shootnig at target
  def ammo_tonnage_per_shot
    @game.ammo_weights.fetch(ammo_category) * ammo_per_shot
  end

  def total_tonnage
    tonnage + heat_tonnage + ammo_tonnage
  end

  def ammo_category
    @data["ammoCategoryID"] || @data["AmmoCategory"]
  end

  def purchasable?
    @data["Description"]["Purchasable"]
  end

  def weapon_effect
    @data["WeaponEffectID"]
  end

  def ignore?
    [
      category == "Melee",
      name == "AI Laser",
      base_name =~ /Flamer/,
      base_name =~ /Infernos/,
      subtype == "TAG",
      subtype == "Narc",
      subtype =~ /\ACOIL/,
      weapon_effect == "WeaponEffect-Artillery_MechMortar",
      weapon_effect == "WeaponEffect-Artillery_Thumper",
    ].any?
  end

  def min_range
    @data["MinRange"]
  end

  def max_range
    @data["MaxRange"]
  end

  def indirect_fire
    @data["IndirectFireCapable"]
  end

  def base_stab_damage
    @data["Instability"]
  end

  def as_json
    {
      base_name:,
      bonus:,
      tonnage:,
      heat:,
      shots:,
      base_damage:,
      ammo_tonnage_per_shot:,
      min_range:,
      max_range:,
      indirect_fire:,
      base_stab_damage:,
      category:,
    }.transform_keys(&:to_s).transform_keys(&:camelize)
  end
end

class BattleTechGame
  extend Memoist

  def initialize(game_root, *dlc_roots)
    @game_root = Pathname(game_root)
    @dlc_roots = dlc_roots.map{|path| Pathname(path)}
  end

  memoize def data_root
    @game_root + "BattleTech_Data/StreamingAssets/data"
  end

  def roots
    [data_root, *@dlc_roots]
  end

  memoize def weapon_files
    roots
      .flat_map{|root| root.glob("weapon/*.json")}
      .select{|n| n.basename.to_s != "WeaponTemplate.json"}
  end

  memoize def weapons
    weapon_files.map{|path| Weapon.new(self, path)}
  end

  memoize def ammobox_files
    roots
      .flat_map{|root| root.glob("ammunitionBox/*.json")}
      .select{|n| n.basename.to_s != "AmmoBoxTemplate.json"}
  end

  memoize def ammoboxes
    ammobox_files.map{|path| AmmoBox.new(path)}
  end

  memoize def ammo_weights
    # MG box occurs twice, but with same ratio
    ammoboxes.to_h{|a| [a.id, a.tonnage.to_f/a.capacity]}.merge("NotSet" => 0.0)
  end

  def inspect
    "BattechGame"
  end

  def as_json
    weapons
      .reject(&:ignore?)
      .map(&:as_json)
  end
end

game = BattleTechGame.new(*ARGV)
puts JSON.pretty_generate(game.as_json)
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Story so far

All the code is on GitHub.

Coming next

In the next episode I'll use these changes to add extra functionality to the app.

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