Dungeon Object Layout

At the moment I am playing around with the Zelda ROM and dungeon object layout. I am reading the Compendium (1.8.4), but there is a lot thats not clear for me. Additionally I study some of the source code from ZScream Magic and Black Magic.

There are three sub types for object type 1. The code in both programs is rather complex for drawing tiles. How does the game determine how to draw an object of type1_subtype1? How does it know how many tiles are used. Can't imagine the code is as complex as in ZM or BM. Is there further information somewhere?

MathOnNapkins disassembly and other docs are the most comprehensive and complete docs for the game we have. Even if it has been like seven years since their last update. Mostly all Alttp tools and editors are based on those research documents.

Although you could probably send a private message to Zarby if he has further information, being that he is coding Zscream Magic or try the Alttp hacking discords, maybe someone knows the technicalities better over there.

MathOnNapkins docs - https://www.zeldix.net/t143-disassembly-zelda-docs
Zarby's Zscream Magic - https://www.zeldix.net/t1565-zscream-magic
ALTTP Speedrunning/Hacking Discord - https://discord.gg/SSufwfA
ALTTP Randomizer Discord - https://discord.gg/MsWxB5K

There is also the source code to Hyrule Magic floating around that you can get your hands on, but from what I've heard, that thing is less documented and further less coded in a proper way that it's really hard to comprehend. You could ask MathOnNapkins on the Alttp hacking discord if you want a documented/updated copy of the HM source.

Thanks for your answer. I will try the discord channels.