Lists of Rooms inside the List in Theme Defintion causes strange generation

[Irbynx]

Version Information: Custom Modpack, MC 1.20.1, Forge 47.3.0
Mod Version: 194

Was designing a custom theme for a modpack and ran into an issue where for every dungeon of that theme that I generated, all rooms of a particular type picked one specific structure (so all hallways picked exclusively "example_hallway_1" and all corners picked exclusively "example_corner_2") - once that structure was picked, the entire dungeon generated only that specific structure for the rest of the dungeon for that room type.

The reason seems to be in the way the generator picks random entries from a list of lists. If a list is formatted the following way - [["hallway_1", "hallway_2", "hallway_3" ... etc]], then the generator will exhibit this behavior - it will pick one entry in the list and then repeatedly use it for the rest of the dungeon. Having a list in the format of [["hallway_1"], ["hallway_2"], ["hallway_3"], ...etc] makes generator pick random options every time. After switching my theme's room definitions from the first format into the second one fixed the issue.

I think the expected behavior should be that both generate random every time, right? Otherwise using the sub-list functionality to, i.e have a list of "rare" rooms would cause these rare rooms to generate in an oversaturated way.

Map of the anomalously generated dungeon as viewed via Xaero's Map mod (note the obviously repeating structures being used):

[AllenSeitz]

This is intentional, but un-intuitive. The intent is to keep similar rooms from appearing in the same dungeon.

As you figured out, most of the time you will want to design the arrays to be more like [ ["room_1"], ["room_2"], ["room_3"], ["room_4"] ]. Especially for custom themes.

Here's a simplified example:

basicHallways = [
["dimdungeons:coalhall_1", "dimdungeons:coalhall_2", "dimdungeons:coalhall_3"],
["dimdungeons:juke_1", "dimdungeons:juke_2", "dimdungeons:juke_3"], 
["dimdungeons:moohall_1", "dimdungeons:moohall_2"],
["dimdungeons:tempt_1", "dimdungeons:tempt_2", "dimdungeons:tempt_3", "dimdungeons:tempt_4"]
]

The intent here is that once one variation of 'coalhall', 'juke', 'moohall', or 'tempt' is chosen, that no other similar rooms from the same family are allowed to appear in the dungeon. But if a dungeon (in this example) has more than 4 hallways then it loops around and makes the same choice again. My solution is to ensure that there are always far more choices than I expect rooms of that type to ever generate. But I don't mention this anywhere.

In other words, making a sub-array of length greater than 1 indicates that the rooms are intended to be exclusive.

[Irbynx]

Thank you for the insight. To clarify, if one is to generate a dungeon with more than 4 hallways with an array of rooms like so:

basicHallways = [ ["ex:hall_1"], ["ex:hall_2"], ["ex:hall_3"], [ "ex:special_hall_1", "ex:special_hall_2", "ex:special_hall_3" ] ]

Would the intended behavior be for ex:hall 1, 2 and 3 to be generating randomly for the dungeon as needed, whereas special_hall 1, 2 and 3 would be selected only once out of the sub-array for the entire dungeon? Or would the behavior instead cause one of the special_halls to be picked, then be generated once every 4 times as hall 1, 2 and 3 end up also generating?

Either way, I believe that providing a clarification in the wiki page for this topic would greatly help in the future for other modpack and/or custom theme designers.

[AllenSeitz]

The first one. Technically what happens is first all of the sub-arrays with more than one choice are collapsed into a single choice. In your example the dungeon might choose "hall_1", "hall_2", "hall_3", and "special_hall_2". Then those 4 choices are shuffled like a deck of cards and dealt out as needed. Rooms are put on the bottom of the deck after being used, not discarded.

The "deck", "looping", is a consequence of I didn't know what else to do when running out of rooms. Theoretically there is enough content in the mod such that looping is never noticed by the player.