November 26, 2025
Open sauce or open source?
S&box is now an open source game engine
Facepunch drops it free; fans hype while skeptics shout “not Source 2”
TLDR: Facepunch open-sourced s&box under a no-strings MIT license, but debate rages because it still relies on Valve’s closed Source 2 tech. Fans are hyped, confused, and amused by spicy code comments, while devs tout prettier terrain and big bug fixes—making this a bold, messy win for indie creators.
Facepunch just tossed the doors wide open: s&box is now free and open source under the MIT license, with code on GitHub. The devs say you can fork it, ship a game, or just peek under the hood. But the top comment mood? “Cool… but it still rides on Valve’s Source 2,” which isn’t open. That sparked the day’s hottest debate: is this a bold gift to devs or “open source with an asterisk”? The team did clarify: the low-level tech comes from Valve, but the editor, UI, networking, and more are their own—and now open.
Meanwhile, the community turned the repo into a spectacle. One user cackled that the code comments are full of “profanity-filled rants,” instantly meme-ifying the commit history. When the site hiccupped, someone dropped the GitHub link like a fire escape. Another wandered in asking if they could use the Team Fortress 2 engine—then discovered that’s a modding toolkit, not this. Techies are also scratching their heads over how s&box adds a “scene-based” workflow on top of Source’s “map-based” roots.
Under the drama, real upgrades landed: prettier terrain with less obvious tile patterns, a huge bug bash (VR rendering fixed), and a cleaner memory system for fewer crashes. Verdict: the code is open, the vibes are chaotic, and everyone’s reading the comments.
Key Points
- •s&box has been open-sourced under the MIT license and is available on GitHub.
- •The engine uses Valve’s Source 2 for low-level systems, while high-level systems (editor, networking, scene system, UI) are written in C#.
- •Terrain updates fix LOD seam issues and add an experimental anti-tiling technique by rotating texture segments.
- •Native memory allocation handling was rewritten, enabling AddressSanitizer and allocation tracing, and the allocator was switched from jemalloc to mimalloc.
- •A large set of bugs were fixed following major play mode changes, including issues with VR rendering, envmaps, swapchain leaks, TextEntry, cursors, size selection, and restoring GameEditorSessions.