recorded per room in the generation result, for a parity trace or a game's own bookkeeping
Optionalmaxlargest room it can fill; a builder wanting only small rooms sets this
Optionalminsmallest room this builder can fill, in cells, on either axis
Optionalweightrelative weight against the other eligible builders; defaults to 1
How one room's interior gets carved.
The generator decides where rooms go and what joins them; a builder decides what a room actually looks like once it has a rectangle to fill. That split is what makes them composable: a game registers a hall, a pillared chamber, a circular vault and a flooded cistern, and any floor is some mixture of them without the generator knowing what a pillar or a cistern is.
mwgships exactly one builder (hallBuilder, a plain filled rectangle, which is what the generator did unconditionally before builders existed) and expects a game to bring the rest, the same boundary every other module here draws around content.