Modding:Encounters and Population

This page is about modding. See the modding overview for an abstract on modding.

There are two primary population systems in Caves of Qud, the legacy EncounterTables.xml system, and the ZoneTemplates.xml+PopulationTables.xml system. Encounter tables are an older system and we prefer to use zone templates + population tables these days, but much of the game is still populated via EncounterTables.xml.

Like ObjectBlueprints.xml, both the EncounterTables.xml and the PopulationTables.xml support use of the Load="Merge" attribute to merge content into existing tables defined by the base game files. This will append entries to the specified table instead of overwriting it.

Many zone template encounters draw objects from dynamically created population tables. Check out the following tags in ObjectBlueprints.xml to see them in use: DynamicObjectsTable, ExcludeFromDynamicEncounters. Some dynamic population tables are created based on the base type of the object, so new objects will begin appearing immediately in areas generated with dynamic population tables unless they are tagged with ExcludeFromDynamicEncounters. Refer to the section below for more information about Dynamic population tables.

The unaffiliated cave systems are one area that is heavily populated with the zone template+population system.

Extending Encounter Tables

You may add new entries to existing encounter tables by including EncounterTables.xml in your mod, using an existing table name and setting the Load="Merge" property on the encountertable tag.

Adding "My New Ammo" to the "Ammo 1" built-in encounter table

<encountertables>
  <encountertable Name="Ammo 1" Load="Merge">
    <objects>
      <object Chance="100" Number="3d6" Blueprint="My New Ammo"></object>
    </objects>
  </encountertable>
</encountertables>

Extending Population Tables

To modify existing populations, you can take a similar approach. For example, the following could be used in a mod's PopulationTables.xml file to add a new type of Wristblade Legendary merchant lair:

  <population Name="GenericLairOwner" Load="Merge">
    <group Name="Options" Load="Merge">  <!-- Add the Load="Merge" attribute to each nested group, mimicking the base game's PopulationTables.xml structure -->
      <object Blueprint="WristbladeMerchant" Weight="20" /> <!-- Insert your new item! -->
    </group>
  </population>

Of course, this would also need to be supplemented with an ObjectBlueprints.xml that defines the new "WristbladeMerchant". It would likely inherit from "BaseMerchant" and have the appropriate parts defined, similar to other legendary merchants.

Full Example Usage

Here is some example XML from a mod that creates a fully functional Six Day Stilt vendor using a combination of Load="Merge" tables and new tables defined by the mod. This is everything that's needed in the mod's PopulationTables.xml file, though this won't work by itself. It would also require an ObjectBlueprints.xml to define the various Blueprint objects that are not included here.

  <!-- Merge new YoyoWinderTent into the game's StiltTents population table -->
  <population Name="StiltTents" Load="Merge">
    <group Name="Types" Load="Merge">
      <table Name="YoyoWinderTent" Weight="4" />
    </group>
  </population>

  <!-- Define the YoyoWinderTent -->
  <population Name="YoyoWinderTent">
    <group Name="Contents" Style="pickeach">
      <object Blueprint="YoyoWinder" Number="1" Hint="Interior" />
      <table Name="YoyoWinderTentContents" />
    </group>
  </population>
  <population Name="YoyoSigns">
    <group Name="Items" Style="pickone">
      <object Blueprint="YoyoSign1" Number="1" Hint="OutsideDoor:1" />
      <object Blueprint="YoyoSign2" Number="1" Hint="OutsideDoor:1" />
      <object Blueprint="YoyoSign3" Number="1" Hint="OutsideDoor:1" />
    </group>
  </population>
  <population Name="YoyoWinderTentContents">
    <group Name="Contents" Style="pickeach">
      <object Blueprint="Torchpost" Number="1" Hint="InsideCorner" />
      <table Name="YoyoSigns" />
      <object Blueprint="Torchpost" Number="1-2" Hint="OutsideDoor:2" />
      <object Blueprint="YoyoWinder Workbench" Number="1-2" Hint="AlongInsideWall" />
      <object Blueprint="Woven Basket" Number="1" />
      <object Blueprint="YoyoWinder Workbench" Number="1" />
      <object Blueprint="Yoyo Oil Pitcher" Number="1-2" Hint="AlongInsideWall" />
      <object Blueprint="Yoyo String Plastifer 3" Number="1" Chance="15" />
      <object Blueprint="Yoyo String Elastyne 3" Number="1" Chance="35" />
      <object Blueprint="Yoyo String Elastyne 5" Number="1" Chance="20" />
      <object Blueprint="Chest" Number="1-2" Hint="AlongInsideWall" />
    </group>
  </population>

Dynamic Tables

The game sometimes uses dynamically generated population tables, which are constructed from objects in ObjectBlueprints.xml.

There are three methods of constructing dynamic tables:

Through the use of DynamicObjectsTable, which identifies all of the objects that have been tagged as belonging to a particular table.
Through inheritance and the use of DynamicInheritsTable.
Through DynamicSemanticTable, which collects all objects that are in the intersection of a set of categories.

DynamicObjectsTable

A DynamicObjectsTable contains all objects that have been tagged as belonging to that table. Here's an example from the definition of shrewd baboon in ObjectBlueprints/Creatures.xml:

<object Name="Shrewd Baboon" Inherits="Baboon">
  <part Name="Render" DisplayName="shrewd baboon" ColorString="&amp;B" />
  <stat Name="AV" Value="3" />
  <stat Name="Intelligence" Boost="1" />
  <stat Name="Hitpoints" Value="20" />
  <property Name="Role" Value="Leader" />
  <tag Name="DynamicObjectsTable:Baboons" />
</object>

Shrewd baboon has been given <tag Name="DynamicObjectsTable:Baboons" />, so it automatically belongs to the Baboons dynamic objects table.

DynamicInheritsTable

A DynamicInheritsTable contains all objects that inherit from another object. For example, here's the population table for GritGateWorkbench population table, which is used to generate the contents of the workbenches that appear in Grit Gate:

<population Name="GritGateWorkbench">
  <group Name="GritGateWorkbench" Style="pickeach">
    <table Name="DynamicInheritsTable:Tool" Chance="15" />
    <table Name="Junk {zonetier}" Chance="15" />
    <table Name="DynamicObjectsTable:EnergyCells" Chance="15" />
  </group>
</population>

This population table has a 15% chance of generating an item from the DynamicInheritsTable:Tool table, which includes any item that is descended (through inheritance) from Tool. This includes basic toolkits, advanced toolkits, pickaxes, and several other items.

A DynamicInheritsTable can be weighted based on the tier of an item by appending :Tier<zonetier>. For example, DynamicInheritsTable:BaseLongBlade:Tier5 will give a weight of 1000 to items of the specified tier, a weight of 100 to items one tier above or below that, a weight of 10 to items two tiers above or below that, and a weight of 1 to all other items. This results in a population table being constructed by the game similar to the following:

Item	Weight
bronze long sword	1
bronze two-handed sword	1
iron long sword	1
two-handed iron long sword	1
steel long sword	1
two-handed steel long sword	1
carbide long sword	10
two-handed carbide long sword	10
folded carbide long sword	100
two-handed folded carbide long sword	100
fullerite long sword	1000
two-handed fullerite long sword	1000
crysteel long sword	100
crysteel great sword	100
flawless crysteel long sword	10
flawless crysteel great sword	10
zetachrome long sword	1
two-handed zetachrome long sword	1
vibro blade	1000

DynamicSemanticTable

A DynamicSemanticTable can generate any object within an intersecting list of categories. Consider the population table for the ruined ward section of Bethesda Susa:

<population Name="BethesdaSusaRuinedWard">
  <!-- Skipping over most of the contents of this table... -->

  <table Chance="80" Number="1-8" Name="DynamicSemanticTable:Medical,Furniture:4:6" Hint="AlongWall" />
  <table Chance="60" Number="1-4" Name="DynamicSemanticTable:Professional,Furniture:2:5" Hint="AlongWall" />
  <table Chance="5" Number="1-3" Name="DynamicSemanticTable:Torture,Furniture:1:5" Hint="AlongWall" />
  <table Chance="5" Number="1-2" Name="DynamicSemanticTable:Child,Furniture:1:5" Hint="AlongWall" />
  <table Chance="5" Number="1-2" Name="DynamicSemanticTable:Normality,Furniture" Hint="AlongWall" />
</population>

Picking out one line of this, DynamicSemanticTable:Medical,Furniture:4:6 is a dynamic table which includes objects that have both <stag Name="Medical" /> and <stag Name="Furniture" /> in their definition. The 4:6 bit will weight objects more heavily as their tier gets closer to 4 or their tech tier gets closer to 6.

Excluding objects from dynamic tables

Finally, it's possible to explicitly exclude an object from all dynamic tables by adding the following tag to it:

<tag Name="ExcludeFromDynamicEncounters" />

This is especially helpful when creating unique or rare NPCs and items, who aren't expected to simply appear in random zones. It is also useful when defining base objects, who serve as a template on which to construct other objects but should not themselves appear in-game.

Debugging population tables

There are two wishes available to make it easier to determine what objects appear in population tables:

population:findblueprint:<blueprint>: shows the probability of a particular blueprint appearing at least once for every population table.
population:generate:<table>#<amount>: generates a given population table the specified number of times, and then shows the frequency of various blueprints among the generated objects.

Both wishes are compatible with dynamic tables.

Additional Info

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