S2SDK

C++ SDK headers and support code for Source 2 games, built as a static library. Targets Counter-Strike 2.

Public headers live under src/public/. Function bodies live in matching .cpp files under src/, so the library links without inline duplicates.

Acknowledgement

This repository is created from https://github.com/alliedmodders/s2sdk/tree/cs2. The commit history was not saved because we don't want to carry out hundreds of MB on each checkout.

Layout

Folder	Purpose
src/public/	Public headers, one subfolder per module.
src/tier0, tier1	Core utilities: containers, strings, convars, keyvalues, memory.
src/mathlib	Vectors, matrices, quaternions, color conversion, SIMD math.
src/entity2	Entity system: handles, identity, keyvalues, variants.
src/schemasystem, schemalib	Schema classes, types and metadata.
src/networksystem, networkstrings	Network messages and string tables.
src/engine2, game	Engine and game interfaces.
src/filesystem, resourcesystem, resourcefile	Files and resources.
src/steamworks	Steamworks API headers.
libs/	Prebuilt tier0 and steam_api import libraries.
protobufs/	protobuf 3.21.8 runtime and generated protos target.

Quick start

Prerequisites

• Windows: Visual Studio with the C++ workload
• Linux: GCC with C++23 support
• XMake

Build

xmake build s2sdk

The s2sdk target pulls in protos and protobuf automatically and merges them into one archive (build_merge_archive).

Use as a dependency

includes("vendor/s2sdk")

target("my-plugin")
    add_deps("s2sdk")

s2sdk exports its include dir (src) and links tier0 and steam_api publicly. Include headers as public/<module>/<name>.h.

Dead-code stripping

Library and consumers are built for section-level garbage collection:

Platform	Compile	Link
Windows	/Gy /Gw	/OPT:REF /OPT:ICF
Linux	-fPIC -ffunction-sections -fdata-sections	-Wl,--gc-sections

Unused functions and data do not reach the final binary.

Updating binaries

tracked_files.json lists Steam depot files (tier0, steam_api) tracked for updates. .github/workflows/sync.yml pulls new versions from Steam depots.

Architecture

s2sdk/
├── src/
│   ├── public/            # Public headers (<module>/<name>.h)
│   ├── <module>/          # Matching .cpp implementations
│   ├── common.cpp         # Shared float helpers
│   └── const.cpp
├── libs/
│   ├── win64/             # tier0.lib, steam_api64.lib
│   └── linuxsteamrt64/    # libtier0.so, libsteam_api.so
├── protobufs/
│   ├── protobuf-3.21.8/   # Protobuf runtime
│   └── protos/            # Source 2 .proto files
├── cpp_properties.lua     # Shared C++ rule
├── tracked_files.json     # Depot files kept in sync
└── xmake.lua

Community

• Issues: Report bugs and request features