How to create new map (mission, scenario)

Mission vs Scenario vs Map

First let's explain these 3 different concepts.

Mission

Mission is basic unit of Nebuchadnezzar.
It connects map and objectives together.
Several mission together can form campaign.
Player always play missions.

Scenario

Scenario is just a special subset of mission.
It's a mission which is not part of any campaign.
Player can play any scenario without any limitation, because all scenarios are unlocked.

Map

Map is data file containg information about specific map.
Stuff like surface layout, buildings etc.

Create mission atom

To create new mission you have to create an atom for it first.

In your mode create def folder. It will contains all def files.
In that folder create mission.lua file.
- The name of the file is important because the type of atom is based on the def file name.
And now let's add some content.

nature_buildings = {
    'base::build.palm.1',
    'base::build.palm.2',
    'base::build.palm.3',
    'base::build.palm.4',
    'base::build.bush.1',
    'base::build.bush.2',
    'base::build.bush.3',
    'base::build.bush.4',
    'base::build.palm.bush.1',
    'base::build.palm.bush.2',
    'base::build.palm.bush.3',
    'base::build.palm.bush.4',
    'base::build.fish.1',
}

First of all, we will prepare some general variable, which we can use in multiple mission atoms.
Beause it's always better to have shared data in some variable.
The variable nature_buildings now contains all nature buildings from the base mod.
Notice the base:: part when referencing atoms. You have to use it because you are referencing atoms from other mod.

irrig_buildings = {
    'base::build.irrig.canal',
    'base::build.irrig.pump',
    'base::build.irrig.bridge.dirty',
    'base::build.irrig.bridge.stone',
}

In the same way we create variable containing all irrigation buildings from the base mod.

mission_base = {
    base_mods = {"base"},
    first_residents_event = 'base::event.first_residents',
    leaving_residents_event = 'base::event.leaving_residents',
    returning_residents_event = 'base::event.returning_residents',
    no_path_residents_event = 'base::event.no_path_residents',
}

Here we prepare variable containing data which are usable in all mission.
We use events from the base mod.
As well as base_mods property which determines from which mods the game should take available terrain data.

atom ('mission.my_first_mission', mission_base,
{
    description = 'description.my_first_mission',
    intro_event = 'event.intro.my_first_mission',
    money_events = {},

    allowed_buildings = ac(
        nature_buildings, ac(
        irrig_buildings, {
        'base::build.road.dirty',
        'base::build.shop.bread',
        'base::build.farm.plant.1',
        'base::build.warehouse.1',
        'base::build.house.lower.1',
    }),

    allowed_monuments = {},
    allowed_templates = {},

    map = 'map.my_first_mission',
    prestige = 'prestige.my_first_mission',
    requests = {},
    demands = {},

    target_population = 300,
    target_prestige = 10,
    target_level_atoms = {'base::level.house.lower.1'},
    target_level_counts = {12},
})

And finaly we can see our new mission atom.
Notice usage of function ac when defining allowed buildings.
- This is helper function avilable in all def files and it can be use for arrays concatenation.
Because not all referenced atoms are from the base base, we will of course have to create them before starting to work with this mission.
- Look at corresponding atoms in base for inspiration.

Create map file

When we have valid mission atom, we can start to create the map itself for the mission.

To create new map use command new_map [mission atom name] [size x] [size y]
After that the game will load the mission with empty map.
It should look like this:

Map surface

The first thing you should fill the map with desired surface.