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Random Spawners

Note

This guide was originally written by developer timothymtorres for /tg/, and has been adapted for Paradise.

Random spawners are an organized tool primarily for mapping to enhance replayability. The spawners can create objects, effects, and structures with different tweakable settings to get the desired outcome. You can make a spawner determine direction, rarity, number of items to spawn, pixel spacing between items, and even spread it over a large tile radius. This lets you control the atmosphere of a location. You could for instance spawn different piles of trash in maint or spawn decoration items for a room to give it more randomized flavor. The choice is yours!

Variables

The following variables are defined in code/game/objects/effects/spawners/random/random_spawner.dm that control how a spawner works.

Var Description
loot A list of possible items to spawn e.g. list(/obj/item, /obj/structure, /obj/effect)
loot_type_path This combines the subtypes and type list with the loot list.
loot_subtype_path This combines only the subtypes (excludes the loot_subtype_path) with the loot list.
spawn_loot_count How many items will be spawned.
spawn_loot_double If the same item can be spawned twice from the loot list.
spawn_loot_split Whether the items should have staggered pixel offsets. This overrides pixel_x/y on the spawner itself.
spawn_all_loot Whether the spawner should spawn all the loot in the list (ignores spawn_loot_count).
spawn_loot_chance The chance for the spawner to create loot (ignores spawn_loot_count).
spawn_scatter_radius Determines how big of a range (in tiles) we should scatter things in.

These variables are set to the following default values for the base object that all objects inherit from:

    /// these three loot values are all empty
    var/list/loot
    var/loot_type_path
    var/loot_subtype_path

    var/spawn_loot_count = 1 // by default one item will be selected from the loot list
    var/spawn_loot_double = TRUE // by default duplicate items CAN be spawned from the loot list
    var/spawn_loot_split = FALSE // by default items will NOT spread out on the same tile
    var/spawn_all_loot = FALSE // by default the spawner will only spawn the number of items set in spawn_loot_count
    var/spawn_loot_chance = 100 // by default the spawner has a 100% chance to spawn the item(s)
    var/spawn_scatter_radius = 0 // by default the spawner will spawn the items ONLY on the tile it is on

However there are some categories that overwrite these default values so pay attention to the folder or category you group your spawner in. For instance the obj/effect/spawner/random/techstorage category overwrites the spawn_all_loot and the spawn_loot_split variables.

/obj/effect/spawner/random/research
    name = "generic research item spawner"
    spawn_loot_split = TRUE
    spawn_all_loot = TRUE

This means any spawner you create under the tech_storage subtype will also have those variables set to that by default. This can be overridden quite easily just be resetting the variables back to the normal state like so:

/obj/effect/spawner/random/research/data_disk
    name = "data disk spawner"
    spawn_all_loot = FALSE // now our loot won't all be spawned
    loot = list(
        /obj/item/disk/data = 49,
        /obj/item/disk/nuclear/fake/obvious = 1,
    )

Template

All the random spawners follow the same template format to keep things consistent and unison.

/obj/effect/spawner/random/INSERT_SPAWNER_GROUP/INSERT_SPAWNER_NAME
    name = "INSERT_SPAWNER_NAME spawner"
    loot = list(
        /obj/item/PATH/INSERT_OBJ_1,
        /obj/item/PATH/INSERT_OBJ_2,
        /obj/item/PATH/INSERT_OBJ_3,
    )

All the capitalized code is the parts where you are supposed to swap out with your objects like so:

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(
        /obj/item/wrench,
        /obj/item/wirecutters,
        /obj/item/crowbar,
    )

Find the path to different objects and add them to the list but try to be consistent with the types of the object and the spawner. For example, a tool spawner shouldn’t have a emag in the loot list!

Probability

Be aware that the loot list uses a weighted chance formula to determine probability. So if there are no numbers set in the loot list then each object defaults to 1 and has the same probability to be selected. For our above example for the /obj/effect/spawner/random/engineering/tools spawner, each item has a 1/3 chance to be spawned. But if we rearranged the values to this:

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(
        /obj/item/wrench = 2,
        /obj/item/wirecutters = 1,
        /obj/item/crowbar = 1,
    )

Then now wrench has a 50% chance of being spawned (2/4), wirecutters has a 25% chance of being spawned (1/4), and crowbar also has a 25% chance of being spawned (1/4). If we add another item into the mix then we get the following:

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(
        /obj/item/wrench = 2,
        /obj/item/wirecutters = 1,
        /obj/item/crowbar = 1,
        /obj/item/weldingtool = 1,
    )

wrench is 40% (2/5), wirecutters is 20% (1/5), crowbar is 20% (1/5), and weldingtool is 20% (1/5). A weighted list has the advantage of not needing to update every item in the list when adding a new item. If the list was based on a straight percent values, then each new item would require to manually go and edit all the items in the list. For big lists that would become very tedious. This is why we use weighted lists to determine probability!

Style

Here are some simple guidelines that you should stick to when making a new spawner:

If all items have the same chance, do not specify weights

Do not put /obj/item = 1 unless other items have different spawn chances.

Good

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(
        /obj/item/wrench = 2,
        /obj/item/wirecutters = 1,
        /obj/item/crowbar = 1,
        /obj/item/weldingtool = 1,
    )

or:

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(
        /obj/item/wrench,
        /obj/item/wirecutters,
        /obj/item/crowbar,
        /obj/item/weldingtool,
    )

Bad

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(
        /obj/item/wrench = 1,
        /obj/item/wirecutters = 1,
        /obj/item/crowbar = 1,
        /obj/item/weldingtool = 1,
    )

Sort the list from highest probability to lowest

Sort from top to bottom. The rarest items for your spawner should be at the bottom of the list.

Good

/obj/effect/spawner/random/contraband/armory
    name = "armory loot spawner"
    loot = list(
        /obj/item/gun/ballistic/automatic/pistol = 8,
        /obj/item/gun/ballistic/shotgun/automatic/combat = 5,
        /obj/item/storage/box/syndie_kit/throwing_weapons = 3,
        /obj/item/grenade/clusterbuster/teargas = 2,
        /obj/item/grenade/clusterbuster = 2,
        /obj/item/gun/ballistic/automatic/pistol/deagle = 1,
        /obj/item/gun/ballistic/revolver/mateba = 1,
    )

Bad

/obj/effect/spawner/random/contraband/armory
    name = "armory loot spawner"
    loot = list(
        /obj/item/storage/box/syndie_kit/throwing_weapons = 3,
        /obj/item/gun/ballistic/automatic/pistol = 8,
        /obj/item/gun/ballistic/revolver/mateba = 1,
        /obj/item/grenade/clusterbuster/teargas = 2,
        /obj/item/gun/ballistic/automatic/pistol/deagle = 1,
        /obj/item/grenade/clusterbuster = 2,
        /obj/item/gun/ballistic/shotgun/automatic/combat = 5,
    )

Always put the loot list at the bottom of your spawner

This is just to keep things organized.

Good

/obj/effect/spawner/random/food_or_drink/donkpockets
    name = "donk pocket box spawner"
    spawn_loot_double = FALSE
    loot = list(
        /obj/item/storage/box/donkpockets/donkpocketspicy,
        /obj/item/storage/box/donkpockets/donkpocketteriyaki,
        /obj/item/storage/box/donkpockets/donkpocketpizza,
        /obj/item/storage/box/donkpockets/donkpocketberry,
        /obj/item/storage/box/donkpockets/donkpockethonk,
    )

Bad

/obj/effect/spawner/random/food_or_drink/donkpockets
    name = "donk pocket box spawner"
    loot = list(
        /obj/item/storage/box/donkpockets/donkpocketspicy,
        /obj/item/storage/box/donkpockets/donkpocketteriyaki,
        /obj/item/storage/box/donkpockets/donkpocketpizza,
        /obj/item/storage/box/donkpockets/donkpocketberry,
        /obj/item/storage/box/donkpockets/donkpockethonk,
    )
    spawn_loot_double = FALSE

Always put a comma at the last item in the loot list

This will make it easier for people to add items to your spawner later without getting frustrating code errors.

Good

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(
        /obj/item/wrench,
        /obj/item/wirecutters,
        /obj/item/crowbar,
    )

Bad

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(
        /obj/item/wrench,
        /obj/item/wirecutters,
        /obj/item/crowbar // <-- missing comma
    )

Keep the same tab formatting for the loot list (unless there is only one item)

Again, this is just good code organization. If there is only one item, then encase that item in loot = list(item).

Good

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(
        /obj/item/wrench,
        /obj/item/wirecutters,
        /obj/item/crowbar,
    )

or

/obj/effect/spawner/random/structure/crate_abandoned
    icon = 'icons/effects/landmarks_static.dmi'
    icon_state = "loot_site"
    spawn_loot_chance = 20
    loot = list(/obj/structure/closet/crate/secure/loot)

Bad

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(
    /obj/item/wrench,
    /obj/item/wirecutters,
    /obj/item/crowbar,
    )

or

/obj/effect/spawner/random/engineering/tools
    name = "Tool spawner"
    loot = list(/obj/item/wrench,
        /obj/item/wirecutters,
        /obj/item/crowbar,
    )

Try to keep the total combined weight of your loot list to sane values (Aim for 5, 10, 20, 50, or 100)

This makes the math probability easier for people to calculate (this is recommended, but not always possible).

Good

/obj/effect/spawner/random/trash/cigbutt
    name = "cigarette butt spawner"
    loot = list(
        /obj/item/cigbutt = 65,
        /obj/item/cigbutt/roach = 20,
        /obj/item/cigbutt/cigarbutt = 15,
    )

Also good:

/obj/effect/spawner/random/trash/botanical_waste
    name = "botanical waste spawner"
    loot = list(
        /obj/item/grown/bananapeel = 6,
        /obj/item/grown/corncob = 3,
        /obj/item/food/grown/bungopit = 1,
    )

Bad

/obj/effect/spawner/random/entertainment/money_large
    name = "large money spawner"
    loot = list(
        /obj/item/stack/spacecash/c1 = 521,
        /obj/item/stack/spacecash/c10 = 378,
        /obj/item/stack/spacecash/c20 = 212,
        /obj/item/stack/spacecash/c50 = 205,
        /obj/item/stack/spacecash/c100 = 71,
        /obj/item/stack/spacecash/c200 = 60,
        /obj/item/stack/spacecash/c500 = 57,
        /obj/item/stack/spacecash/c1000 = 41,
        /obj/item/stack/spacecash/c10000 = 12,
    )

Do not put empty items in the loot list

Instead use the spawn_loot_chance var to control the chance for the spawner to spawn nothing.

Good

/obj/effect/spawner/random/structure/crate_abandoned
    name = "locked crate spawner"
    spawn_loot_chance = 20
    loot = list(/obj/structure/closet/crate/secure/loot)

Bad

/obj/effect/spawner/lootdrop/crate_spawner
    name = "lootcrate spawner"
    loot = list(
        "" = 80
        /obj/structure/closet/crate/secure/loot = 20,
    )

Avoid making a spawner that is a duplicate

We don’t want copy-cat spawners that are almost identical. Instead merge spawners together if possible.

Good

/obj/effect/spawner/random/contraband/armory
    name = "armory loot spawner"
    icon_state = "pistol"
    loot = list(
        /obj/item/gun/ballistic/automatic/pistol = 8,
        /obj/item/gun/ballistic/shotgun/automatic/combat = 5,
        /obj/item/storage/box/syndie_kit/throwing_weapons = 3,
        /obj/item/grenade/clusterbuster/teargas = 2,
        /obj/item/grenade/clusterbuster = 2,
        /obj/item/gun/ballistic/automatic/pistol/deagle,
        /obj/item/gun/ballistic/revolver/mateba,
    )

Bad

/obj/effect/spawner/lootdrop/armory_contraband
    loot = list(
        /obj/item/gun/ballistic/automatic/pistol = 8,
        /obj/item/gun/ballistic/shotgun/automatic/combat = 5,
        /obj/item/gun/ballistic/automatic/pistol/deagle,
        /obj/item/gun/ballistic/revolver/mateba
    )

/obj/effect/spawner/lootdrop/armory_contraband/metastation
    loot = list(
        /obj/item/gun/ballistic/automatic/pistol = 8,
        /obj/item/gun/ballistic/shotgun/automatic/combat = 5,
        /obj/item/storage/box/syndie_kit/throwing_weapons = 3,
        /obj/item/gun/ballistic/automatic/pistol/deagle,
        /obj/item/gun/ballistic/revolver/mateba
    )