Multiplayer for Ratchet & Clank

Logo courtesy of Discord user _triippy_

This is a multiplayer mod for the PS3 HD release of the original 2002 Ratchet & Clank. It runs on console and emulator thanks to PS3-CKit by TGE.

For the server side, check out bordplate/Lawrence.

We also have a community over on Discord for discussing the multiplayer and Randomizer mods.

Installation

Go to the releases and download the .pkg file. Install on either console or emulator the way you install .pkg files normally. The game will show up on the XMB/Home screen on your PS3 or emulator.

You must have a legal copy of the european version (NPEA00385) of Ratchet & Clank already installed to start the mod.

Structure

Launcher /app/

This is the main executable for the game launcher, it only spawns our modded EBOOT.

Loader /loader/

The loader consists out of handwritten assembly to load the mod.sprx from the game directory. When building, we also decrypt, patch and resign a copy of the original game code such that we have a static binary with our loader code.

PRX module /prx/

The PRX module is loaded by the injected loader into the game process. From that point on the PRX loader will communicate with the ELF loader to share addresses with each other, allowing both to interoperate. The sharing of addresses is how the bulk of data, including code, can be moved to the SPRX where code space is less of a concern than it is in the ELF. The PRX module loads its own configuration and runs its submodules accordingly. Submodules have the ability to hook functions and insert custom functionality however they see fit.

This module contains all the multiplayer logic in the game.

The build scripts

The build scripts are activated through Makefiles in the respective directories, but the bulk of the work is done in the tools placed in the tools directory. Those tools are used to generate the build files (assembly, linkerscripts and makefiles) used to generate the code needer for the ELF loader, PRX loader and function hooks.

The build is configured through 2 files:

• The userconfig.mk for user settings such as paths
• The game config (config_RC1.mk) for game target specific settings.

In userconfig.mk are defined:

• The paths to locations used for building, such as the RPCS3 installation directory
• The target game ID, version and serial.

The config_*.mk file defines the game specific addresses used to build the loader and PRX module.

Building

I strongly suggest you have a look at how the building works in practice by looking at the Github Action workflow in this repository.

To build this project on Windows 10, you need:

• chocolatey
• make, installed through chocolatey install make
• python 3.8, available through py -3
• PS3 SDK compilers (check GitHub Action workflow mentioned above)
• PS3_SDK environment variable that points to the root of the PS3 SDK
• Cygwin/MinGW/WSL to access Linux tools such as sed and awk. Must be available in the environment path.
• RPCS3
• text editor of choice, such as vscode
• a copy of Ratchet & Clank (NPEA00385) installed in RPCS3 in {RPCS3_INSTALL_DIR}/dev_hdd0/game/NPEA00385
• bit of luck
• coffee

Base patches

This base patch provides the loader with the needed import functions to load the SPRX module at game boot. And including some patches to change behavior of some library calls that determine the game content paths for the game. Only the rc1.txt patch file is actually applied, but the "legacy" yaml file contains comments. The base patches can be found in the 'basepatches' folder.

Setup

To perform the build, execute:

make

If all goes well there shouldn't be any errors, and a .pkg installer file should be created in the /build/ folder, including a /build/PS3_GAME/USRDIR folder with the app launcher that you can start directly from RPCS3. Subsequent builds update the PS3_GAME folder and when you restart the game in RPCS3, the updates should be applied.