Developer builds Earth-sized GTA-style sandbox from real map data and Claude

A developer known as @_chuckyc is building an open-world game that recreates the entire planet using OpenMapTiles and other public-domain mapping data, describing it as a mix of GTA and Apple Maps. The custom C++ engine uses Metal and Vulkan renderers and runs on all Apple platforms except Apple Watch, with much of the code generated by Anthropic's Claude Opus 5.5 across three Macs. There is no actual game yet — just a sandbox with weather systems, procedurally generated building interiors, vehicles and a photo mode.

• World is streamed from OpenMapTiles and public mapping data
• C++ engine with Metal and Vulkan runs on all Apple platforms except Watch
• Claude Opus 5.5 writes much of the code across three Macs
• Features weather with hurricanes, procedural interiors, vehicles and photo mode