ACORN

More Than an AI Mod

ACORN started as an attempt to make Assetto Corsa’s offline racing feel less robotic. It grew into a full enhancement platform: a DLL plugin loaded through Assetto Corsa’s official — but long-abandoned — plugin API.

DLL plugins for AC have a small C interface. At load, the game builds its own ACPlugin wrapper for the DLL (keeping the Sim* and module handle), then binds six optional exports via GetProcAddress — a missing export only logs an error:

bool acpGetName(wchar_t* name);                  // plugin writes its UTF-16 display name
bool acpInit(IACPPluginHost* host);              // one-time setup; host is the game's
                                                 // ACPlugin object — the bridge into the sim
bool acpUpdate(ACCarState* state, float dt);     // per-tick car state
bool acpOnGui(ACPluginContext* ctx);             // GUI callback
bool acpGetControls(ICarControlsProvider** out); // return true to replace the car's
                                                 // controls provider (official input takeover)
bool acpShutdown();                              // teardown

The quiet superpower is acpGetControls: when it returns true, the game installs the plugin’s controls provider on the car via CarAvatar::setControlsProvider — a sanctioned path to taking over driving inputs. ACORN uses this contract as its load mechanism, then detours AIDriver::acquireControls to observe and improve the offline AI where the API stops.

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