S&box
S&box is a platform and game development toolkit developed by Facepunch studio powered by 
Source 2. Initially, the development was based on Unreal Engine 4, but as soon as 
Half-Life: Alyx came out, Facepunch immediately requested the engine branch of the newly-published game. A few weeks later Valve gave Facepunch access to the terabyte large repository, after which, in 2020, S&box's transition to Source 2 was announced. This is the first (and currently only) time that Source 2 was licensed to third-party developers.
User Access
S&box is currently in closed developer testing, as of May 5, 2022, the automated queue has been shut down indefinitely due to the termination of the test recruitment in December 2021.
Previously, access was available from the addon developers page, which now takes care of redirecting users to the Asset.Party home page.
Release Date
An exact release date is unknown, but Facepunch plans to release S&box around 2023, according to a post on the project’s description page: “Our plan is to get to a releasable state over the next 6–12 months, then improve it over 10–20 years.”
The approximate dates for the completion of primary work were first announced by Garry Newman on February 19, 2022, on the official S&box Discord server:
Addons
S&box currently supports 4 types of add-ons: Template:MdQuote
Maps
Mappers are provided with a modified version of the Source 2 Hammer map editor, with some parts exposed for C# scripting for increased flexibility.
Addon control panel
In the addons menu in the dev tools, you can restrict map selection for your game mode. You can limit it to specific curated maps or maps tagged with supporting the game mode.
Publication
Currently, maps cannot be launched directly from the game mode, so they have to be released as a separate addon (one for each map). The map is published by clicking on a special button in the addons menu in the developer toolkit.
Characteristics
| Unlimited for models, but 32768 units (624.23 m / 2048 ft) for meshes | |
| The player currently sees approximately 78740 units (2 km / 6561,68 ft) in front of him |
Shaders
S&box supports HLSL Shader Model 3.0, 4.0 and 5.0. You can create your own shaders and customize their interface for the material editor.
Sounds
Currently, the sounds are arranged in an extremely primitive way due to the content associated with them cut from the engine.
An analog of Steam Audio using C# is currently being developed. In addition, a convenient sound editor based on graph nodes is being developed.
Programming
S&box uses C#, which is significantly more powerful than the Lua scripting language used in Garry's Mod, as it is a fully-fledged scripting language.
Currently, the C# API and tools are in heavy development. API breaks happen semi-frequently and there are areas of the engine bindings that are underdeveloped. There are also APIs completely missing at this time. These restrictions in many cases make at best engine integration impossible or tedious. At worst it bars you from implementing a feature entirely.
