rosetta plugin

The Rosetta backend — Foldit's core molecular-mechanics engine. This is the plugin behind the everyday folding moves: energy minimization, sidechain repacking, backbone rebuilding, and the score you are trying to improve.

Unlike the other native plugins (which are Rust), Rosetta is a C++ plugin. It wraps the Rosetta macromolecular modeling suite through a bridge that exports the Foldit plugin vtable.

Operations

The buttons in plugin.toml map to Rosetta actions:

Button	Op	What it does
Wiggle	ActionGlobalMinimize	Energy-minimize the whole structure (gradient descent on the score)
Wiggle Backbone / Sidechains	ActionGlobalMinimize{Backbone,Sidechains}	Minimize only those degrees of freedom
Shake	ActionRepack	Repack sidechain rotamers to lower energy
Shake Mutate	ActionRepackDesign	Repack with mutations allowed (sequence design)
Idealize / Idealize SS	ActionIdealize{,SS}	Reset peptide-bond geometry to ideal values
Rebuild	ActionRebuild	Rebuild backbone segments from the fragment library

It also contributes UI panels (for example the Ramachandran map under ui/dist/rama_map.mjs) and ships the Rosetta scoring database under assets/database/.

How it is built

This is the one plugin that is not a simple cargo build, so it is worth understanding the moving parts:

• The bridge source is the rosetta-interactive tree. It is several GB and is not a committed submodule — the build recipe clones it on demand into deps/rosetta-interactive (gitignored), pinned to a fixed commit.
• It statically links molex. The build first compiles libmolex.a from crates/molex (with the c-api feature) and links it into the bridge, so the bridge and the host must agree on molex's binary wire format. A host on a newer molex wire version than the bridge was built against will be rejected at runtime — rebuild the bridge after a molex bump.
• Committed prebuilts. Because the from-source build is expensive, a prebuilt bridge binary is committed per platform under prebuilt/<target-triple>/. At runtime the loader prefers a freshly built binary in local/ (gitignored) and falls back to prebuilt/.

Build (or rebuild) it from source with:

cargo xtask setup-plugins rosetta --clean

--clean wipes the cached CMake build directory. Use it after a molex or toolchain change so the bridge actually relinks the new libmolex.a instead of a stale one. The result installs into local/; promote it to prebuilt/ by copying it there once you have confirmed it works.

Kind

kind = "native"; its binary basename rosetta_interactive resolves to the platform library name (librosetta_interactive.dylib / .so / rosetta_interactive.dll). The shim exports foldit_plugin_vtable from that existing dylib, so there is no separate plugin binary.