From ce26606d17ba7c71041b10e4b74ad25e9d9fd028 Mon Sep 17 00:00:00 2001 From: alemidev Date: Tue, 7 Feb 2023 12:33:32 +0100 Subject: docs: added README.md --- README.md | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 README.md (limited to 'README.md') diff --git a/README.md b/README.md new file mode 100644 index 0000000..1615cc9 --- /dev/null +++ b/README.md @@ -0,0 +1,22 @@ +# lillero-loader +*don't do coremods* + +A simple LaunchPlugin loading bare ASM patches into our beloved block game. + +## Why +Until minecraft 1.12, modifying minecraft game code wasn't too esoteric: it was necessary to register as "CoreMod", but Forge would then load your mod when minecraft itself was loading, allowing to lookup classes and patch them. +Since 1.13+ `net.minecraft.launchwrapper.Launch` and `net.minecraftforge.fml.relauncher.IFMLLoadingPlugin` are no longer available, replaced by cpw's modlauncher. This makes a new approach necessary. + +## How +Modlauncher loads some Java services at startup (using builtin [ServiceLoader](https://docs.oracle.com/javase/8/docs/api/java/util/ServiceLoader.html) mechanism), allowing to load arbitrary classes and modules when launching Minecraft. +More specifically, the `ILaunchPluginService` is loaded before game classes are put in memory, and is passed all game classes for patching. This allows us to create a custom Launch Plugin (this project) that will load and apply arbitrary patches at start time. +Patches must be defined themselves as services inside each mod, implementing `IInjector` (from [lll](https://git.fantabos.co/lillero)) They must define in which class they will patch, and which method, and then implement an `inject()` method which will be called with the correct Method Node. +Note that, as of now, Searge names must be used for methods and fields. + +### I know what I'm doing, spill your beans +Basically, our `ILaunchPluginService` implements 3 methods which are called in 3 phases: + * `addResources()` : will be called first for each external mod that was found, providing an absolute path to the jar. Our LaunchPlugin will try to load `IInjector` services from each of these resources, saving them for later. + * `handlesClass()` : will be called for each game class modlauncher discovered. Our LaunchPlugin will signal that it wants to change classes for which an `IInjector` was registered. + * `processClassWithFlags()` : will be called for each game class which was signaled before, allowing to apply modifications to it. + +*Technically, `handlesClass()` and `processClassWithFlags()` are called concurrently, but assuming they don't make the explanation easier.* -- cgit v1.2.3-56-ga3b1