Focus Trees

The following section delineates a stylization guide for Millennium Dawn and coding best practices for the Hearts of Iron IV feature “Focus Trees”.

Link to Focus Tree Modding Wiki

Best Practices

• Use relative_position_id for focus alignment and tree positioning
• Implement logging in completion rewards: log = "[GetDateText]: [Root.GetName]: Focus TAG_your_focus"
• Avoid empty mutually_exclusive and available blocks
• Omit default values: cancel_if_invalid = yes, continue_if_invalid = no, available_if_capitulated = no
• Always include ai_will_do with historical game and game options checks
• Maintain consistent spacing (1 line between elements)
• Create balanced focus trees without clear military/economy/political branches
• Add search filters for all focuses
• Remove non-used code or commented out code if there is not intention to return to the tree section
• Utilize and review scripted effects and triggers where applicable
• Use variables instead of magic numbers
• Implement starting ideas that weaken nations, resolvable through focus trees/decisions.
  • This ensures there is a possible goal or focus to strive for to give the game some type of depth and consistency
• Limit permanent effects to 5, use timed ideas for additional effects
• Balance focus trees for flavor, not overpowering nations

Millennium Dawn Specific Code Styling Requirements

• The focus tree file should start with one of the following requirements:
  • 00_ for system requirements. This should only be reserved for specific contexts such as the titlebar_styles.txt file
  • 01/02/03/04_ for shared or joint focus tress such as the European Union or the African Union
  • 05_ for country specific focus trees
  • NOTE: The number does not mean anything, but it helps the team understand and forces a specific load order for focus trees. I.e. we can load all of the shared ones, but we cannot load country specific ones
• The ID of a focus should be the first line of the focus. It should also follow the standard <TAG>_focus_name_here pattern
• The icon should be second line of the of the focus
• The X and Y coordinates should be the next section of the focus tree definitions
• relative_position_id should be defined after the x and y coordinates
• allow_branch should be defined before prerequisite as it determines whether a focus branch is available in the first place (think of this like allowed)
• prerequisite and mutually_exclusive should be grouped together as they pertain to the section of the tree delineating structure of the focus tree
• available, bypass and cancel should be grouped together as these are specific to the triggers of a focus tree and as such should be grouped together
• select_effect, completion_reward and bypass_effect should be grouped together as these are specific to the effects of a focus tree
• ai_will_do is and always should be the last definition of the focus tree

Example Focus Tree Structure

focus_tree = {
    id = greece_focus

    country = {
        factor = 0
        modifier = {
            tag = GRE
            add = 100
        }
    }

    shared_focus = USoE001
    shared_focus = POTEF001

    continuous_focus_position = { x = 2350 y = 1200 }
}

focus = {
	id = SER_free_market_capitalism
	icon = blr_market_economy

	x = 5
	y = 3
	relative_position_id = SER_free_elections

	cost = 5

	# allow_branch = { }
	prerequisite = { focus = SER_western_approach }
	# mutually_exclusive = { }
	search_filters = { FOCUS_FILTER_POLITICAL }

	available = {
		western_liberals_are_in_power = yes
	}
	# bypass = { }
	# cancel = { }

	# will_lead_to_war_with = TAG -- Only needed if you are giving a nation a war goal or preparing for conflict with another nation

	# complete_tooltip = { } -- This is not needed unless you want a specific thing always displayed
	# select_effect = { }
	completion_reward = {
		log = "[GetDateText]: [Root.GetName]: Focus SER_free_market_capitalism"
		add_ideas = SER_free_market_idea
	}
	# bypass_effect = { }

	ai_will_do = {
		base = 1
	}
}

Decisions

The following section delineates a stylization guide for the Millennium Dawn and coding best practices for the Hearts of Iron IV features Decisions/Missions.

Link to Decision/Modding Wiki

Best Practices

• Use fire_only_once only when necessary
• Include proper logging in effects
• Structure decisions with clear visibility and availability conditions
• Implement proper AI behavior

Example Decision Structure

URA_world_opr = {
    allowed = { original_tag = URA }
    icon = GFX_decision_sovfed_button

    cost = 50
    days_remove = 400

    visible = {
        country_exists = OPR
        OPR = {
            OR = {
                has_autonomy_state = autonomy_republic_rf
                has_autonomy_state = autonomy_kray_rf
                has_autonomy_state = autonomy_oblast_rf
                has_autonomy_state = autonomy_okrug_rf
            }
        }
    }

    complete_effect = {
        log = "[GetDateText]: [Root.GetName]: Decision URA_world_opr"
        OPR = { country_event = { id = subject_rus.121 days = 1 } }
    }

    ai_will_do = {
        factor = 10
    }
}

Events

Best Practices

• Use is_triggered_only for triggered events
• Include proper logging
• Use major = yes sparingly for news events
• Structure events with clear options and effects

Example Event Structure

country_event = {
    id = france_md.504
    title = france_md.504.t
    desc = france_md.504.d
    picture = GFX_france_mcdonalds_bombing
    is_triggered_only = yes

    option = {
        name = france_md.504.a
        log = "[GetDateText]: [This.GetName]: france_md.504.a executed"
        set_party_index_to_ruling_party = yes
        set_temp_variable = { party_popularity_increase = -0.01 }
        set_temp_variable = { temp_outlook_increase = -0.01 }
        add_relative_party_popularity = yes

        ai_chance = {
            base = 1
        }
    }
}

Ideas

Best Practices

• Include allowed_civil_war for civil war tags
• Use proper logging in on_add
• Structure modifiers clearly
• Implement balanced effects
• Performance: Remove unnecessary allowed = { always = no } statements as they add drag to performance - since always = no is the default behavior, these lines provide no functional benefit while consuming processing resources

Example Idea Structure

BRA_idea_higher_minimun_wage_1 = {
    name = BRA_idea_higher_minimun_wage
    allowed_civil_war = { always = yes }
    on_add = { log = "[GetDateText]: [THIS.GetName]: add idea BRA_idea_higher_minimun_wage_1" }

    picture = gold

    modifier = {
        political_power_factor = 0.1
        stability_factor = 0.05
        consumer_goods_factor = 0.075
        population_tax_income_multiplier_modifier = 0.05
    }
}

Code Formatting Rules

Indentation

• Increase tabulation by 1 when entering a new scope {
• Decrease tabulation by 1 when leaving a scope }
• Use tabs, not spaces
• Maintain consistent indentation

Brackets

• Place closing brackets on the same line as the starting word
• Avoid excessive whitespace
• Keep simple checks on one line when appropriate

Subideology Localization Format

TAG.conservatism: "£PARTY_ICON (ABBRV) - NAME OF PARTY"
TAG.conservatism_icon: "£PARTY_ICON"
TAG.conservatism_desc: "(Dominant Ideology of the Party) - NAME OF PARTY (NAME OF LANGUAGES IN ALL NATIVE LANGUAGES FOR THE COUNTRY, ABBRV)\n\n(Description)"

Example:

MOR.conservatism: "£MOR_NRI (RNI) - National Rally of Independents"
MOR.conservatism_icon: "£MOR_NRI"
MOR.conservatism_desc: "(Classic Liberalism) - National Rally of Independents (Arabic: Altajamue Alwataniu Lil'ahrar, French: Rassemblement National des Indépendants, Standard Moroccan Tamazight: Agraw Anamur y Insimann, RNI)\n\nNominally a social-democratic party, the party often cooperates with other parties with liberal orientation and is heavily described as pro-business and liberal. Formed in 1978 by then-Prime Minister Ahmed Osman the party has consistently remained a major player in Moroccan politics. Furthermore, the party is a national observer of the Liberal International and is affiliated with the Africa Liberal Network and the European People's Party."