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bonnie

How to replace monsters?

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Hello. I cannot seem to find a tutorial or detailed explanation of any kind relating to replacing monsters in vanilla doom, or atleast boom. If anyone can provide or point me towards one, I would be extremely grateful. I am uninterested in zdoom based ports.

I also have some questions about replacing monsters that I need addressed, even if you are unable to provide a tutorial or explanation.

1) Which things can be replaced? Can I replace the boss brain? Will it retain it's property of ending the level when killed? Can I replace monster spawners and monster targets (I assume not since they don't have any sprites to replace)? Can I replace other things, such as torches or hanging bodies? If so, what are the limitations on those?

2) What are the limitations on the monster's abilities? Can monsters have special attacks and abilities or special projectiles, or do they have to reuse projectiles and coding from the monster they replace/any pre-existing monster? For example, could the Afrit in Scythe 2 use custom sprites for the fireballs and rockets without replacing the originals, and could it use something like maybe homing mancubus fireballs, all in vanilla doom?

3) If the answer to number 2 is that you can only rehash existing code for monsters, does anyone have any boom-compatible custom monsters that I could potentially test with?

Warning: I'm not pretending to be stupid, as most people assume. I'm actually stupid. Please talk to me as if I have literally no idea what you're talking about, because I really, truly don't. It took me over a week to figure out how to correctly add textures without breaking my wad because people would keep explaining how to do it as if I already knew exactly how to do it. :(

Thank you in advance friends.

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All thing types have common properties, flags, and states - their values define the thing's behavior, and can be changed freely and arbitrarily. However, some things also have special properties that can't be changed (Zombiemen dropping clips, Archviles being untargetable by other monsters, Cyberdemons and Masterminds being immune to splash damage...), and all state functions (codepointers) that spawn other things are hardcoded to spawn a specific thing type (if you've redefined it, it just spawns the redefined one).

For this reason, there is only a fixed amount of thing types that can be fired as projectiles - even though you could potentially redefine ALL things in the whole game to act like projectiles, only the things that were originally the Imp fireball, Cacodemon fireball, and so on, have functions that can fire them. You can change how these projectiles behave, and you can change where these functions are called from, though.

Overally, there is only a fixed amount of thing types, and a fixed amount of states in the pool that's shared by all thing types and player's weapons combined. Only this limits the number of added monsters, decorations or things with non-standard special behavior. You can redefine as many thing types and states as you want and as you can, at the cost of breaking whatever those thing types or states were originally used for.

EDIT:
The feature I've been describing above, that allows modifying game objects in vanilla or Boom, is called DEHACKED.
The classic DEHACKED editing tutorial is here: http://www.aspectsweb.co.uk/dehacked/index.html
The modern DEHACKED editor is here: http://www.teamhellspawn.com/exl/whacked4/
The utility that can apply a DEHACKED patch onto vanilla executable (not necessary if you don't personally want to play a DEHACKED-modified game in the original vanilla executable, because unlike vanilla, source ports just read and process DEHACKED patches themselves) is here: https://www.doomworld.com/idgames/utils/exe_edit/dhe31 (it's also a DEHACKED editor)

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bonnie said:

I'm actually stupid. Please talk to me as if I have literally no idea what you're talking about, because I really, truly don't. It took me over a week to figure out how to correctly add textures without breaking my wad because people would keep explaining how to do it as if I already knew exactly how to do it.


Haha, I've felt like that since the first day I started editing Doom, especially when trying to read archaic and incomplete instruction txt-files, well-meaning but incomprehensible advice, etc. Just be stubborn, don't give up, keep looking around, ask questions and keep experimenting.

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I'm just gonna bump this since scifista42's answer is really confusing and nobody has even attempted to explain how to replace monsters or where to even begin. :(

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Will take some time but I'll work on a tutorial over the next week-ish. Could definitely help out those still interested in using dehacked.

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