retcomm-rbengine
Library · 2026-08-12
The snapshot ring behind save states and rewind: a platform-agnostic rollback engine shared across the recomp ecosystems.
retcomm-rbengine is the ecosystem's rollback engine: a platform-agnostic library for snapshots, save states, and rewind. It began life inside psxrecomp's runtime and was lifted out with the PlayStation-specific types removed, so any recompilation host can use it. MIT licensed, maintained by TechnicallyComputers.
What it does
Its modules manage frame timing and a tick-keyed snapshot ring. The snapshot ring is the substrate that save states are built on, and the same machinery enables rewind.
Tomba on PSXRecomp, the runtime this library was lifted out of
Which projects use it
PSXRecomp builds on it for save states and rewind, both shown publicly in the Tomba showcase video (2026-08-12).
Save states and rewind, shown off in Tomba
Game-specific pieces, such as savestate serialization and state digests, stay in each engine and bind in through the library's hooks.