LBA1:Block library

Block library
Extension	BL1
Occurence	LBA1
Colour
Programs supporting this format
LBArchitect
References
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Block libraries organize Bricks in groups, that are easier to manage during Grid editing.

Specification

Abstract: a LBA1 layout is a collection of bricks, positioned in a three dimensional "subspace" of specific size. Take, for example, a treasure chest: it has a ground area of 3*2 bricks and is 2 bricks high. so the subspace has a size of 3*2*2 bricks. then all bricks, that represent this chest, are packed into the treasure chest layout.

So every brick in LBA1 can be addressed by two indices: - the index of the layout, it belongs to (which is ambiguous, i assume, because a brick can belong to multiple layouts) - the position index of the brick within the specific layout. those two indices are provided by the entries of the grid file (see GR1 file extension)

The layouts have obvious advantage in an editor because you can place logical units instead of single bricks (Little Big Architect uses layouts) though i wonder why Adeline put them into the game.

open questions: what's the purpose of the first word (16 bits) in each index entry of the brick indices.

the layout index and the brick index within the layout both have to be decreased by one to get the real indices. a value of zero for these indices (before decreasing) indicates an empty brick!

BL1 layout files are found in lba_bll.hqr

file structure

1. header pointing on data entries each data entry contains dimension entries and index data
   the header contains up to 256 pointer entries, who define the positions of the actual data entries in the file. each data entry represents one layout.
2. dimension entries
   the dimension entry is a row of 3 bytes, each providing the length of the subspace in x-, y-, z-direction. so the row 1,3,3 means: the subspace has a width (x) of 1, a height (y) of 3 and a depth (z) of 3.
3. index data
   the index data contains 4 bytes of data for each brick in the layout, so it's size in bytes is 4*x*y*z.

let's call these blocks of 4 bytes "brick entries". the last word (last 2 bytes) of these brick entries is the actual index of the brick in lba_brk.hqr. the first word seems to be layout-specific, but i wasn't able to find out what it's used for yet.

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Information provided by: Zink and Omni