lycanthorn-asl

LiveSplit autosplitter for Lycanthorn II - Rain of Beasts.

Features

• Load Removal
• Auto start
• Auto split points
  • Level entries/exits
  • Run end

TODO

• Auto split points
  • Key collection
  • Boss kills

Technical Info

Lycanthorn II is built with GZDoom 4.3.1. This engine is open source, which is always helpful when reverse engineering an application. To find the static values outlined below, I used the following process:

• Locate a reference to the target value in the source code which is close to a unique string literal.
• Using a reverse engineering tool such as x64dbg, search for the string literal in the game's exe.
• Locate the assembly instruction correspoinding to the reference to the target variable.
• Either:
  • Copy the constant pointer used by the instruction and use it directly. This is the simpler option, but if the game updates the pointer will probably change.
  • Extract a unique signature which can be used to identify this instruction, then use signature scanning to locate it at runtime and extract the pointer. This is more complicated, and will introduce a small amount of overhead during the autosplitter's initialisation, but should be much more resilient to updates.

gameaction

The gameaction global variable is defined by GZDoom in d_event.h. The type of this variable is gameaction_t, an enum defined as follows:

enum gameaction_t : int
{
	ga_nothing,
	ga_loadlevel,
	ga_newgame,
	ga_newgame2,
	ga_recordgame,
	ga_loadgame,
	ga_loadgamehidecon,
	ga_loadgameplaydemo,
	ga_autoloadgame,
	ga_savegame,
	ga_autosave,
	ga_playdemo,
	ga_completed,
	ga_slideshow,
	ga_worlddone,
	ga_screenshot,
	ga_togglemap,
	ga_fullconsole,
	ga_resumeconversation,
};

The autosplitter uses this variable for auto start functionality by checking when the value is ga_newgame (2).

level.levelnum

The level global variable is defined by GZDoom in g_level.cpp. It has type FLevelLocals, a struct which stores information about the active level. FLevelLocals is defined in g_levellocals.h. This is a large struct with many properties, but the one used for the autosplitter is levelnum (offset 0x940). This is a numeric identifer for the current level, which is used by the autosplitter to tell when the player has moved to another level.

nextlevel

NOTE: The autosplitter no longer uses this variable, since level.levelnum fits the use case better.

The nextlevel static variable is defined by GZDoom in g_level.cpp. It has type FString, a string wrapper. When loading a new level, the variable is updated with the name of the level to load. However, the variable is not updated when loading a save game. The autosplitter uses this variable for transition splits.

Map Names/Numbers

Below is a mapping from internal map names/numbers to descriptions of those maps:

• TITLE / 0 - Title Screen
• Map01 / 1 - Intro Cutscene
• MAP02 / 2 - Overworld
• MAP03 / 3 - Canyon
• MAP04 / 4 - Lighthouse
• MAP05 / 5 - Observatory
• MAP06 / 6 - Pyramid
• MAP07 / 7 - Volcano
• MAP08 / 8 - Swamp
• MAP09 / 9 - Fish
• MAP10 / 10 - Tundra
• MAP11 / 11 - Nosferatu's Castle
• MAP12 / 12 - End Cutscene
• MAP13 / 13 - Intro Castle