Building & Compiling

Prerequisites

• CMake 3.10 or higher
• MSVC (Visual Studio 2022 recommended), since the project uses MSVC-specific compiler flags (/W3, /MP, /MT, /EHsc)
• Windows, which is the only supported build target (the CMakeLists.txt explicitly checks if(NOT WIN32) and errors out)

Note

The codebase has platform code for Xbox 360, Xbox One, PS3, PS4, and PS Vita, but the CMake build system only targets Windows 64-bit right now. The other platforms use their own SDK build systems (Visual Studio solutions, SNC makefiles, etc.) which are not included.

Required Asset Directories

You need to provide these directories yourself. They are not included in the repository.

Media & Resources

These are the core content files the game needs to run:

Directory	What’s in it
Minecraft.Client/music/	Background music files (played through Miles Sound System)
Minecraft.Client/Common/Media/	Media archive containing bundled game data
Minecraft.Client/Common/res/	Resources: textures, fonts, GUI assets, mob textures
Minecraft.Client/Common/DummyTexturePack/	Fallback texture pack used when no other pack is loaded

Platform Media

Each platform has its own media directory with platform-specific assets:

• Minecraft.Client/DurangoMedia/ (Xbox One)
• Minecraft.Client/OrbisMedia/ (PS4)
• Minecraft.Client/PS3Media/ (PS3)
• Minecraft.Client/PSVitaMedia/ (PS Vita)
• Minecraft.Client/Windows64Media/ (Windows 64-bit, this is the one you need for PC builds)

Runtime DLLs

These DLLs need to be in the working directory at runtime:

File	What it is
x64/Debug/iggy_w64.dll	Iggy SWF/Flash UI runtime
x64/Debug/mss64.dll	Miles Sound System runtime

Redistributable

• Minecraft.Client/redist64/ contains redistributable runtime files

4J Libraries (per platform)

Each platform has its own set of 4J Studios pre-compiled libraries:

Directory	Contains
Minecraft.Client/Windows64/4JLibs/	4J_Input, 4J_Storage, 4J_Profile, 4J_Render_PC (release _r and debug _d variants)
Minecraft.Client/Xbox/4JLibs/	Xbox 360 4J libraries
Minecraft.Client/Durango/4JLibs/	Xbox One 4J libraries
Minecraft.Client/PS3/4JLibs/	PS3 4J libraries
Minecraft.Client/Orbis/4JLibs/	PS4 4J libraries
Minecraft.Client/PSVita/4JLibs/	PS Vita 4J libraries

Only the Windows64 libraries are needed for PC builds.

Middleware (per platform)

Each platform needs its own middleware binaries:

Middleware	Directories
Miles Sound System	Miles/ inside each platform directory
Iggy UI	Iggy/ inside each platform directory (includes headers in include/ and libs in lib/)
Sentient Telemetry	Sentient/ inside each platform directory (includes headers in Include/)

PlayStation-Specific

Only needed if you’re targeting PlayStation (not required for PC builds):

• Minecraft.Client/PS3_GAME/ (PS3 game data)
• Minecraft.Client/PS4_GAME/ (PS4 game data)
• Minecraft.Client/sce_sys/ (Sony system files)
• Minecraft.Client/TROPDIR/ (Trophy data)
• Minecraft.Client/PS3/PS3Extras/DirectX/ (DirectX compatibility headers for PS3)
• Minecraft.Client/PS3/PS3Extras/HeapInspector/ (Memory debugging tools)
• Minecraft.Client/PS3/PS3Extras/boost_1_53_0/ (Boost library for PS3)
• Minecraft.Client/Common/Network/Sony/ (Sony network platform manager)

Other

• Minecraft.Client/common/dlc/ (DLC content files, lowercase “common”)
• Minecraft.Client/durango/sound/ (Xbox One sound files, lowercase)
• Minecraft.Client/xbox/MinecraftWindows.rc (Windows resource file)
• Minecraft.Client/xbox/MinecraftWindows.ico (Application icon)
• Minecraft.Client/xbox/small.ico (Small application icon)

Build Steps

1. Get the Required Assets

Collect all the assets listed above. At minimum for a Windows build you need:

• The Common/res/, Common/Media/, and Common/DummyTexturePack/ directories
• The Windows64Media/ directory
• The Windows64/4JLibs/, Windows64/Iggy/, Windows64/Miles/, and Windows64/Sentient/ directories
• The runtime DLLs (iggy_w64.dll, mss64.dll)
• The resource file and icons from xbox/

2. Set Up the Source

Place the LCEMP Minecraft.Client and Minecraft.World source folders alongside the CMakeLists.txt. Your directory structure should look like:

LCEMP/
├── CMakeLists.txt
├── cmake/
│   └── Sources.cmake
├── Minecraft.World/
│   ├── *.h / *.cpp
│   └── x64headers/
├── Minecraft.Client/
│   ├── *.h / *.cpp
│   ├── Common/
│   ├── Windows64/
│   └── ...
└── Assets/              # Working directory (set via LCEMP_WORKING_DIR)

3. Generate the Build

mkdir build
cd build
cmake .. -G "Visual Studio 17 2022" -A x64

This generates a Visual Studio 2022 solution targeting x64. You can also use other generators:

# Visual Studio 2019
cmake .. -G "Visual Studio 16 2019" -A x64

# Ninja (for faster builds)
cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Release

4. Build

# Release build
cmake --build . --config Release

# Debug build (enables debug menus and debug overlay)
cmake --build . --config Debug

Or open the generated .sln file in Visual Studio and build from there.

5. Set the Working Directory

The game needs a working directory to find its assets. CMake sets this via the LCEMP_WORKING_DIR variable:

cmake .. -G "Visual Studio 17 2022" -A x64 -DLCEMP_WORKING_DIR="C:/path/to/your/assets"

If not set, it defaults to an Assets/ folder next to the CMakeLists.txt. In Visual Studio, this is configured as the debugger working directory via VS_DEBUGGER_WORKING_DIRECTORY.

6. Copy Runtime DLLs

Make sure iggy_w64.dll and mss64.dll are in the output directory (next to the built exe) or in the working directory.

7. Run

Minecraft.Client.exe

Or run with launch arguments (see below).

CMake Configuration Details

MinecraftWorld Target (Static Library)

Type: STATIC library (.lib)

Compile definitions (Release):
  _LARGE_WORLDS
  _LIB
  _CRT_NON_CONFORMING_SWPRINTFS
  _CRT_SECURE_NO_WARNINGS
  _WINDOWS64

Compile definitions (Debug, adds):
  _DEBUG_MENUS_ENABLED
  _DEBUG

Include directories:
  Minecraft.World/
  Minecraft.World/x64headers/

MinecraftClient Target (Win32 Executable)

Type: WIN32 executable (.exe)

Compile definitions (Release):
  _LARGE_WORLDS
  _CRT_NON_CONFORMING_SWPRINTFS
  _CRT_SECURE_NO_WARNINGS
  _WINDOWS64

Compile definitions (Debug, adds):
  _DEBUG_MENUS_ENABLED
  _DEBUG

Include directories:
  Minecraft.Client/
  Minecraft.Client/Windows64/Iggy/include/
  Minecraft.Client/Xbox/Sentient/Include/

Link libraries:
  MinecraftWorld.lib (the static library built above)
  d3d11.lib
  XInput9_1_0.lib
  Windows64/Iggy/lib/iggy_w64.lib
  Windows64/Miles/lib/mss64.lib
  Windows64/4JLibs/libs/4J_Input_r.lib (or _d for Debug)
  Windows64/4JLibs/libs/4J_Storage_r.lib (or _d for Debug)
  Windows64/4JLibs/libs/4J_Profile_r.lib (or _d for Debug)
  Windows64/4JLibs/libs/4J_Render_PC.lib (or _PC_d for Debug)

Compiler Flags (MSVC)

Flag	Purpose
/W3	Warning level 3 (moderate warnings)
/MP	Multi-process compilation (compiles multiple .cpp files in parallel)
/MT	Multi-threaded static CRT for Release (matches 4J libs)
/MTd	Multi-threaded static debug CRT for Debug
/EHsc	C++ exception handling (synchronous exceptions only)

The CRT linkage (/MT vs /MTd) is critical. The 4J libraries were compiled with the static multi-threaded CRT, so the game must match. Using /MD (dynamic CRT) will cause linker errors.

Source File Lists

Source files are listed in cmake/Sources.cmake in two variables:

• MINECRAFT_WORLD_SOURCES (706 .cpp files)
• MINECRAFT_CLIENT_SOURCES (454 .cpp files, including Common/ subdirectory sources and Windows64/ platform sources)

CMake prepends the module directory path to each filename, so the source lists use relative paths like "Tile.cpp" and "Common/UI/UIScene.cpp".

Launch Arguments

Argument	Usage	Description
-name	-name <username>	Sets your in-game username. Shows up in multiplayer for other players
-ip	-ip <targetip>	Manually connect to a server IP if LAN discovery doesn’t find it
-port	-port <targetport>	Override the default port (25565) if the host changed it in source

Example:

Minecraft.Client.exe -name Steve -ip 192.168.0.25 -port 25565

If you don’t pass -name, the game uses a default username. If you don’t pass -ip, the game uses LAN discovery (UDP broadcast on port 25566) to find local servers.

Networking Constants

These are defined in WinsockNetLayer.h and can be changed if needed:

Constant	Default	Purpose
WIN64_NET_DEFAULT_PORT	25565	TCP port for game connections
WIN64_NET_MAX_CLIENTS	7	Max remote clients (host + 7 = 8 players)
WIN64_NET_RECV_BUFFER_SIZE	65536	TCP receive buffer size per connection
WIN64_NET_MAX_PACKET_SIZE	3 MB	Max single packet size
WIN64_LAN_DISCOVERY_PORT	25566	UDP port for LAN broadcast/discovery
WIN64_LAN_BROADCAST_MAGIC	0x4D434C4E	Magic bytes in broadcast packet (“MCLN”)
WIN64_LAN_BROADCAST_PLAYERS	8	Max player slots advertised

Compile Definitions Reference

Define	Where	Purpose
_LARGE_WORLDS	Both targets	Enables large world support. Changes the lighting cache type from unsigned int to __uint64, increases coordinate range
_WINDOWS64	Both targets	Selects Windows 64-bit platform layer. Guards platform-specific code blocks
_LIB	World only	Indicates static library compilation
_DEBUG_MENUS_ENABLED	Debug only	Enables debug options menu, debug overlay, debug console, schematic tools
_DEBUG	Debug only	General debug flag, enables assertions and extra validation
_CRT_NON_CONFORMING_SWPRINTFS	Both targets	Allows old-style swprintf without buffer size parameter
_CRT_SECURE_NO_WARNINGS	Both targets	Suppresses MSVC “unsafe function” warnings for strcpy, sprintf, etc.

Other platform defines you’ll see in the codebase (not used in the CMake PC build):

Define	Platform
_XBOX	Xbox 360
_DURANGO	Xbox One
__PS3__	PlayStation 3
__ORBIS__	PlayStation 4
__PSVITA__	PlayStation Vita

Troubleshooting

Linker errors about unresolved symbols in 4J libs

Make sure you’re using the matching CRT configuration. The 4J libraries use static multi-threaded CRT (/MT). If your project uses /MD, you’ll get mismatched CRT linker errors. The CMakeLists.txt handles this with CMAKE_MSVC_RUNTIME_LIBRARY.

Missing iggy_w64.dll or mss64.dll at runtime

Copy these DLLs to the same directory as your built .exe, or to the working directory. The game will crash on startup if it can’t find them.

Can’t find assets / black screen

Check that the working directory (LCEMP_WORKING_DIR) points to where your game assets are. The game expects to find texture packs, media archives, and fonts in that directory.

Build takes forever

The project has ~1,160 .cpp files across both targets. Use the /MP flag (already set in CMake) for parallel compilation. With Ninja generator instead of MSBuild, builds can be faster too.

Connection refused in multiplayer

Make sure the host is running on port 25565 (TCP) and the LAN discovery port 25566 (UDP) is not blocked by your firewall. Both players need to be on the same LAN for discovery to work, or use the -ip flag to connect directly.