2077-gps-mod/README.md

2077 Edge Weight Mod

Experimental Cyberpunk 2077 GPS route-weighting mod tooling.

Feasibility

Cyberpunk exposes a native gamegpsGPSSystem, but the current public RTTI dump does not expose script-callable methods for replacing or overriding the GPS planner. The useful surfaces are generated traffic resources:

• worldTrafficPersistentResource.data.lanes
• worldTrafficLanePersistent.length
• worldTrafficLanePersistent.maxSpeed
• worldTrafficLanePersistent.flags
• worldTrafficLanePersistent.playerGPSInfo
• worldTrafficPersistentLaneConnectionsResource.data
• worldTrafficConnectivityOutLane.exitProbabilityCompressed
• worldTrafficConnectivityOutLane.isSharpAngle
• worldTrafficLanePersistentFlags.Highway
• worldTrafficLanePersistentFlags.GPSOnly

The in-game GPS path is computed natively over generated traffic graph data. A full replacement planner would require native hooks or patching the game executable. A feasible REDmod-style mod has to patch generated graph resources and test which fields the native planner actually consumes.

Current Implementation

Current active work is a RED4ext shim under red4ext/EdgeWeightGPS. It has confirmed the world-map GPS route path runs through the native async traffic route pipeline, not the script-facing RunGPSQuery/UpdateGPSQuery helpers. The shim can log the query lifecycle, async traffic result handoff, and route postprocess stages.

A later spatial edge-cost prototype hooked the native local GPS edge-cost callback at 0x44f838 and successfully changed thousands of candidate edge costs in live route-producer calls. A controlled in-game inversion test still produced byte-identical final GPSQueryResultFetch route records before and after flipping highway weights from nearly free to extremely expensive. Treat that hook as a useful local-search diagnostic, not the final player GPS weighting surface.

An experimental traffic candidate scorer hook at RVA 0x8d46cc proved the game does consult traffic lane flags while selecting route/projection candidates: highway, road, and pavement flags were visible live and the hook changed their scores. That detour currently crashes during load, so it is disabled by default in source and disabled in the local game install as EdgeWeightGPS.dll.disabled. It should be treated as evidence and an RE lead, not a playable mod.

The older data-only tooling remains in the repo for reference:

This repo currently contains WolvenKit-export patchers:

python3 tools/patch_traffic_lanes.py exported-json-dir patched-json-dir
python3 tools/patch_lane_connections.py all.traffic_persistent.json all.lane_connections.json patched.lane_connections.json

patch_traffic_lanes.py recursively scans WolvenKit JSON exports for lanes arrays that look like worldTrafficLanePersistent data and applies configurable speed weighting:

• highways get boosted toward a preferred GPS speed in the game's lane scale
• regular roads keep a moderate speed floor
• pavement, crosswalk, and disabled traffic lanes are left alone
• optional non-highway speed caps can make highways more attractive

In-game testing disproved maxSpeed as the main GPS routing lever: even highway speed 120 did not change GPS routes, although freeway traffic visibly moved faster. Treat speed patches as traffic simulation experiments, not route weighting.

patch_lane_connections.py patches all.lane_connections by raising highway-enter/stay edge probabilities and lowering competing non-highway exits. That candidate loaded in game, but live testing did not show a GPS routing change.

After patching, deserialize the JSON back into CR2W and pack the resulting resources into an archive.

The toolbox now has WolvenKit CLI installed:

toolbox run --container 2077 bash -lc '$HOME/.dotnet/tools/cp77tools --help'

See docs/tooling.md for the end-to-end archive build flow. See docs/traffic-system-debrief.md for the detailed feasibility and traffic graph notes.

Status

A conservative speed archive, an aggressive speed archive, and a connection probability archive were built from the local Flatpak Steam Phantom Liberty install. All zz_edge archives are currently disabled in the game folder.

The RED4ext plugin is also currently disabled for normal play:

Cyberpunk 2077/red4ext/plugins/EdgeWeightGPS/EdgeWeightGPS.dll.disabled

Cyberpunk 2077/archive/pc/mod/zz_edge_weight_gps_highway_probability.archive.disabled

Build outputs are ignored by git. Experimental archives and RED4ext DLL builds should be enabled one at a time and tested from a cold boot.