- Features of an Auto Splitter
- How an Auto Splitter works
- The Auto Splitting Language - ASL
- Sandboxed Auto Splitters
- Adding an Auto Splitter
- Additional Resources
LiveSplit has integrated support for Auto Splitters. An Auto Splitter can be one of the following:
- A Script written in the Auto Splitting Language (ASL).
- A WebAssembly module that uses the new cross-platform, sandboxed Auto Splitting Runtime.
- A LiveSplit Component written in any .NET compatible language.
- A third party application communicating with LiveSplit through the LiveSplit Server.
LiveSplit can automatically download and activate Auto Splitters that are LiveSplit components, WebAssembly modules, or ASL scripts.
Currently we recommend writing an ASL script, which has the most extensive support for all the features you might need. If you are feeling more adventurous, you can start looking into writing an auto splitter for the new cross-platform, sandboxed Auto Splitting Runtime here. Sandboxed auto splitters are currently more limited, but they will become the main way to write auto splitters in the future.
An Auto Splitter can provide any of the following features:
Game Time can either be Real Time without Loads or an actual Game Timer found in the game. This depends on the game and the speedrun community of that game. If the game has been run in Real Time for multiple years already, introducing a new timing method might not be worth it.
An Auto Splitter, as the name suggests, can also provide automatic splits to increase the accuracy of the individual segment and split times. An Auto Splitter might not necessarily implement Automatic Splits for every single split available since the runner might want to have some additional splits that are not supported by the Auto Splitter used.
Not every Auto Splitter automatically starts the timer. For some games, the Auto Splitter can't tell whether the runner just wants to start the game to practice something or actually wants to do a run.
An Auto Splitter can automatically reset the timer. This might be useful for games where going back to the main menu always means that the run is over. This is a bit dangerous though, as the runner might not have wanted to reset there. Think twice before implementing this functionality into your Auto Splitter.
Auto Splitters can work in one or multiple of the following ways:
- It can read the RAM, interpret the values, and toggle any of the actions described above based on these values. The RAM addresses might not always be the same. Therefore, the Auto Splitter might need to follow a so called Pointer Path. This is what most Auto Splitters do and what is directly supported by the Auto Splitting Language.
- It can scan the game's RAM to find a value and toggle any of the actions based on these values. Doing a memory scan is slower than following a Pointer Path.
- It can read the game's log files, parse them, and toggle actions based on those. This works, but is usually fairly delayed, which is why this isn't that great of a solution.
- It can read the game's standard output stream. This only works if the game actually writes valuable information to the standard output, which is rare. Also, Steam prevents this method since in order to read the standard output, you need to start the game's process through the Auto Splitter, which Steam won't let you do.
A Pointer Path is a list of Offsets + a Base Address. The Auto Splitter reads the value at the base address and interprets the value as yet another address. It adds the first offset to this address and reads the value of the calculated address. It does this over and over until there are no more offsets. At that point, it has found the value it was searching for. This resembles the way objects are stored in memory. Every object has a clearly defined layout where each variable has a consistent offset within the object, so you basically follow these variables from object to object.
Cheat Engine is a tool that allows you to easily find Addresses and Pointer Paths for those Addresses, so you don't need to debug the game to figure out the structure of the memory.
The Auto Splitting Language is a small scripting language made specifically for LiveSplit Auto Splitters. It has a few advantages and disadvantages over normal Components.
Advantages:
- ASL Scripts are easy to maintain.
- There's no need to update the Script for new LiveSplit versions.
- No Visual Studio or any compiler is needed; you can write it in Notepad.
Disadvantages:
- Currently only provides Boolean settings in the GUI for the user to change.
An ASL Script contains a State Descriptor and multiple Actions which contain C# code.
The State Descriptor is the most important part of the script and describes which game process and which state of the game the script is interested in. This is where all of the Pointer Paths, which the Auto Splitter uses to read values from the game, are described. A State Descriptor looks like this:
state("PROCESS_NAME")
{
POINTER_PATH
POINTER_PATH
...
}
If the script needs to support multiple versions of the game, you can specify an optional version identifier:
state("PROCESS_NAME", "VERSION_IDENTIFIER")
...
The PROCESS_NAME is the name of the process the Auto Splitter should look for. The Script is inactive while it's not connected to a process. Once a process with that name is found, it automatically connects to that process. A Process Name should not include the .exe. Even advanced scripts that use other ways to access the game's memory require a State Descriptor to define which process LiveSplit is supposed to connect to.
The optional VERSION_IDENTIFIER can be any arbitrary string you wish to use. Note that the script can define multiple State Descriptors for different processes/games. These optional features are extremely useful for emulators.
POINTER_PATH describes a Pointer Path and has two ways to declare:
VARIABLE_TYPE VARIABLE_NAME : OFFSET, OFFSET, OFFSET, ...;
VARIABLE_TYPE VARIABLE_NAME : "BASE_MODULE", OFFSET, OFFSET, OFFSET, ...;
The variable type VARIABLE_TYPE describes the type of the value found at the pointer path. It can be one of the following:
| Type | Description |
|---|---|
| sbyte | Signed 8-bit integer |
| byte | Unsigned 8-bit integer |
| short | Signed 16-bit integer |
| ushort | Unsigned 16-bit integer |
| int | Signed 32-bit integer |
| uint | Unsigned 32-bit integer |
| long | Signed 64-bit integer |
| ulong | Unsigned 64-bit integer |
| float | 32-bit IEEE floating-point |
| double | 64-bit IEEE floating-point |
| bool | Boolean |
| string<length> | String (e.g. string255) |
| byte<length> | Byte array (e.g. byte255) |
The variable name VARIABLE_NAME can be any variable name you choose, describing what is found at the pointer path. The naming is up to you, but should be distinct from the other variable names.
The optional base module name BASE_MODULE describes the name of the module the Pointer Path starts at. Every *.exe and *.dll file loaded into the process has its own base address. Instead of specifying the base address of the Pointer Path, you specify the base module and an offset from there. If this is not defined, it will default to the main (.exe) module.
You can use as many offsets OFFSET as you want. They need to be integer literals, either written as decimal or hexadecimal.
The State Variables described through the State Descriptor are available through two State objects: current and old. The current object contains the current state of the game with all the up-to-date variables, while the old object contains the state of the variables at the last execution of the ASL Script in LiveSplit. These objects are useful for checking for state changes. For example, you could check if the last level of a game was a certain value and is now a certain other value, which might mean that a split needs to happen.
LiveSplit's internal state is also available through the object timer. This is an object of the type LiveSplitState and can be used to interact with LiveSplit in ways that are not directly available through ASL.
After writing a State Descriptor, you can implement multiple actions such as splitting and starting the timer. These actions define the logic of the Auto Splitter based on the information described by the State Descriptor. An action looks like this:
ACTION_NAME
{
C# CODE
}
You can think of Actions like functions that are automatically called by the ASL Component. These functions can only interact with each other or LiveSplit via the special variables the environment provides.
All of the actions are optional and are declared by their name ACTION_NAME followed by a code block CODE. You trigger the action by returning a value. Returning a value is optional though; if no value is returned, the action is not triggered. Some actions are only executed while LiveSplit is connected to the process.
Actions are implemented in C#. You can use C#'s documentation for any questions you may have regarding the syntax of C#.
These actions are repeatedly triggered while LiveSplit is connected to the game process.
The name of this action is update. You can use this for generic updating. In each update iteration, this is run before the timer control actions, which e.g. means if you set a value in vars in update you can then access it in start on the same update cycle.
Explicitly returning false will prevent the actions isLoading, gameTime, reset, split, and start from being run. This can be useful if you want to entirely disable the script under some conditions (e.g. for incompatible game versions). See Order of Execution for more information.
The name of this action is start. Return true whenever you want the timer to start. Note that the start action will only be run if the timer is currently not running.
The name of this action is split. Return true whenever you want to trigger a split.
The name of this action is reset. Return true whenever you want to reset the run.
Explicitly returning true will prevent the split action from being run. This can be useful in some cases, but may also cause issues for some scripts. See Order of Execution for more information.
The name of this action is isLoading. Return true whenever the game is loading. LiveSplit's Game Time Timer will be paused as long as you return true.
NOTE: Make sure the timer is set to "Game Time" in the layout! Failure to do so will cause the timer to keep running, as if isLoading had returned false or isLoading weren't triggered at all.
The name of this action is gameTime. Return a TimeSpan object that contains the current time of the game. You can also combine this with isLoading. If isLoading returns false, nothing, or isn't implemented, LiveSplit's Game Time Timer is always running and syncs with the game's Game Time at a constant interval. Everything in between is therefore a Real Time approximation of the Game Time. If you want the Game Time to not run in between the synchronization interval and only ever return the actual Game Time of the game, make sure to implement isLoading with a constant return value of true.
Understanding the order and conditions under which timer control actions are executed can help you avoid issues in your script where variables appear to be set improperly, actions appear to be skipped, and more. Every update iteration follows this process when running actions:
updatewill always be run first. There are no conditions on the execution of this action.- If
updatedid not explicitly returnfalseand the timer is currently either running or paused, then theisLoading,gameTime, andresetactions will be run.
- If
resetdoes not explicitly returntrue, then thesplitaction will be run.
- If
updatedid not explicitly returnfalseand the timer is currently not running (and not paused), then thestartaction will be run.
While a broader suite of events exist in LiveSplit, three are also available as ASL actions. The onStart, onSplit and onReset actions will be triggered when the timer is started, split, and reset respectively.
The name of this action is startup. This action is triggered when the script is first loads. This is the place where you can put initialization that doesn't depend on being connected to the process and the only place where you can add Custom Settings.
The name of this action is shutdown. This action is triggered whenever the script is entirely stopped, for example when the Auto Splitter is disabled, LiveSplit exits, the script path is changed or the script is reloaded (e.g. during development of the ASL script).
The name of this action is init. This action is triggered whenever a game process has been found according to the State Descriptors. This can occur more than once during the execution of a script (e.g. when you restart the game). This is the place to do initialization that depends on the game, for example detecting the game version.
The name of this action is exit. This action is triggered whenever the currently attached game process exits.
Actions have a few hidden variables available.
A dynamic object which can be used to store variables. Make sure the variables are defined (for example in startup or init) before trying to access them. This can be used to exchange data between Actions.
init { vars.test = 5; }
update { print(vars.test.ToString()); }
You can also store variables like this in current and the value will be in old on the next update.
When you set version in init, the corresponding State Descriptor will be activated. When there is no State Descriptor corresponding to the version, the default one will be activated.
The default is the first defined State Descriptor with no version specified, or the first State Descriptor in the file if there is none with no version specified.
The string you set version to will also be displayed in the ASL Settings GUI.
state("game", "v1.2")
{
byte levelID : 0x9001;
}
state("game", "v1.3")
{
byte levelID : 0x9002;
}
init
{
if (modules.First().ModuleMemorySize == 0x123456)
version = "v1.2";
else if (modules.First().ModuleMemorySize == 0x654321)
version = "v1.3";
}
update
{
if (version == "") return false;
print(current.levelID.ToString());
}
Many actions are triggered repeatedly, by default approximately 60 times per second. You can set this variable lower to reduce CPU usage. This is commonly done in startup or init.
refreshRate = 30;
Used to add and access Settings.
These variables depend on being or having been connected to a game process and are not available in the startup or exit actions and only partly available in shutdown (might be null).
State objects representing the current and previous states.
split { return current.levelID != old.levelID; }
The currently connected Process object.
update { if (game.ProcessName == "snes9x") { } }
The modules of the currently connected process. Please use this instead of game.Modules! Use modules.First() instead of game.MainModule.
Provides a means to read memory from the game without using the State Descriptor.
vars.exe = memory.ReadBytes(modules.First().BaseAddress, modules.First().ModuleMemorySize);
vars.test = memory.ReadValue<byte>(modules.First().BaseAddress + 0x9001);
vars.test2 = memory.ReadString(modules.First().BaseAddress + 0x9002, 256);
vars.test3 = new DeepPointer("some.dll", 0x9003, vars.test, 0x02).Deref<int>(game);
vars.test4 = memory.ReadString(modules.Where(m => m.ModuleName == "some.dll").First().BaseAddress + 0x9002, 256);
ASL script settings are stored either with the Layout if you are using the Scriptable Auto Splitter component or with the Splits if you activated the script in the Splits Editor (so make sure to save your Layout or Splits accordingly when exiting LiveSplit if you changed settings).
The Auto Splitter Settings GUI has some default settings to allow the user to toggle the actions start, reset and split. If the checkbox for an action is unchecked, the return value of that action is ignored (but the code inside the action is still executed). So for example if the checkbox for start is unchecked, returning true in the start action will have no effect.
You can access the current value of the basic settings through the attributes settings.StartEnabled, settings.ResetEnabled and settings.SplitEnabled. This is only for informational purposes, for example if your script needs to do something depending on whether the action was actually performed or not, ignoring the return value is done automatically.
Actions that are not present in the ASL script or empty will have their checkboxes disabled.
You can define custom boolean settings for your script in the startup action and then access the setting values as configured by the user in the other actions. If you have custom settings defined, they will be shown in the GUI for the user to check/uncheck. They will appear in the same order you added them in the ASL script.
You can define settings in the startup action by using the settings.Add(id, default_value = true, description = null, parent = null) method:
// Add setting 'mission1', enabled by default, with 'First Mission' being displayed in the GUI
settings.Add("mission1", true, "First Mission");
// Add setting 'mission2', enabled by default, with 'mission2' being displayed in the GUI
settings.Add("mission2");
// Add setting 'mission3', disabled by default, with 'mission3' being displayed in the GUI
settings.Add("mission3", false);
You can access the current value of a setting in all actions other than startup by accessing settings:
// Do something depending on the value of the setting 'mission1'
if (settings["mission1"]) { }
If you want to organize the settings in a hierarchy, you can specify the parent parameter. Note that the parent has to be the id of a setting that you already added:
// Add setting 'main_missions'
settings.Add("main_missions", true, "Main Missions");
// Add setting 'mission1', with 'main_missions' as parent
settings.Add("mission1", true, "First Mission", "main_missions");
Settings only return true (checked) when their parent setting is true as well. The user is unable to toggle settings that have their parent unchecked, and they will be grayed out to indicate they are disabled.
Any setting can act as a parent setting, so you could for example do the following to go one level deeper (continuing from the last example):
// Add setting 'mission1_part1', with 'mission1' as parent
settings.Add("mission1_part1", true, "First part of Mission 1", "mission1");
The setting mission1_part1 will only be enabled, when both mission1 and main_missions are enabled.
When the parent parameter is null or omitted, the setting will be added as top-level setting, unless settings.CurrentDefaultParent is set to something other than null:
// Add top-level setting 'main_missions'
settings.Add("main_missions");
settings.CurrentDefaultParent = "main_missions";
// Add setting 'mission1', with the parent 'main_missions'
settings.Add("mission1");
settings.CurrentDefaultParent = null;
// Add top-level setting 'side_missions'
settings.Add("side_missions");
Using settings.CurrentDefaultParent can be useful when adding several settings with the same parent, without having to specify the parent every time.
You can add a tooltip to settings that appears when hover over the setting in the GUI. This can be useful if you want to add a bit more information. After adding the setting, use settings.SetToolTip(id, tooltip_text) to set a tooltip:
settings.Add("main_missions", true, "Main Missions");
settings.SetToolTip("main_missions", "All main story missions, except Mission A and Mission B");
Used for debug printing. Use DbgView to watch the output.
print("current level is " + current.levelID);
There are some advanced memory utilities not covered here. You can find them here.
You can test your Script by adding the Scriptable Auto Splitter component to your Layout. Right-click on LiveSplit and choose "Edit Layout..." to open the Layout Editor, then click on the Plus-sign and choose "Scriptable Auto Splitter" from the section "Control". You can set the Path of the Script by going into the component settings of the Scriptable Auto Splitter. To get to the settings of the component you can either double click it in the Layout Editor or go into to the Scriptable Auto Splitter Tab of the Layout Settings. Once you've set the Path, the script should automatically load and hopefully work.
Reading debug output is an integral part of developing ASL scripts, both for your own debug messages which you can output with print() and any debug messages or error messages the ASL Component itself provides.
The program DebugView can be used for a live view of debug output from the ASL Component.
For errors, you can also check the Windows Event Logs, which you can find via:
Control Panel ➞ Search for Event Viewer ➞ Open it ➞ Windows Logs ➞ Application ➞ Find the LiveSplit Errors
Some might be unrelated to the Script, but it'll be fairly obvious which ones are caused by you.
It is also possible to provide an auto splitter as a WebAssembly module. These auto splitters get executed through the new Auto Splitter Runtime, which has several benefits:
- The runtime is cross platform. It can run on Windows, macOS, and Linux.
- The runtime is sandboxed. All auto splitters running on the new runtime are fully sandboxed and it's impossible for an auto splitter to harm the user. The user is also protected from the auto splitter crashing, which will not affect the timer itself.
- The auto splitters can be written in many different languages, such as Rust, C, C++, JavaScript, TypeScript, Go, and more.
- The runtime isn't tied to just LiveSplit and can be used with other timers or even run inside of the Auto Splitting Runtime Debugger which allows you to debug the auto splitters more easily.
There is one downside to auto splitters written for the new runtime however. The fact that they are sandboxed and cross platform means that there may be certain functionality, that you may need for your auto splitter to work, that is not supported yet.
Right now Rust is the language that has the best support. If you want to create an auto splitter using the new runtime, you can follow the instructions over here: Rust Auto Splitter Template
If you need help writing an auto splitter for the new runtime, make sure to
visit the #auto-splitting-v2 channel in the Speedrun Tool Development
Discord.
If you implemented an Auto Splitter and want to add it to the Auto Splitters that are automatically being downloaded by LiveSplit, feel free to add it to the Auto Splitters XML. Just click the link, click the icon for modifying the file and GitHub will automatically create a fork, branch and pull request for you, which we can review and then merge in.
Any kind of abuse in an Auto Splitter will result in an immediate ban.
- Speedrun Tool Development Discord
- List of ASL Scripts to learn from, automatically created from the Auto Splitters XML and filterable by different criteria
- Example: Simple Autosplitter with Settings
