GitHub - retroplasma/earth-reverse-engineering: WIP

README.md

Earth to OBJ file downloader

npm install
node index.js [octant] [max_level]

# example.jpg
node index.js 20527061605273514 20

Notes

"https://kh.google.com/rt/?/?"
 - ?: planet
       - "earth"
       - "mars"
       - ...
 - ?: resource
       - "PlanetoidMetadata"
       - "BulkMetadata/pb=!1m2!1s❶!2u❷"
          - ❶: octant path
          - ❷: epoch
       - "NodeData/pb=!1m2!1s❸!2u❹!2e❺(!3u❻)!4b0"
          - ❸: octant path
          - ❹: epoch
          - ❺: texture format
          - ❻: imagery epoch (sometimes)

General info:
 - Everything is stored in an octree.

Roles of resources:
 - PlanetoidMetadata points to first BulkMetaData.
 - BulkMetaData points to other BulkMetaData and to NodeData.
 - NodeData contains actual meshes and textures.

Versioning:
 - BulkMetaData and NodeData are versioned using epoch numbers.
 - PlanetoidMetadata provides epoch of first BulkMetaData.
 - BulkMetaData provides epochs of underlying resources.
 - Current version of a resource can be determined recursively.
 
NodeData:
 - Vertex Buffer:
    - 8 bytes per point: X,Y,Z,W,U,U,V,V
    - XYZ: position, W: octant mask, UV: texture coordinates
 - Texture:
    - Format 1: JPEG
    - Format 6: S3 DXT1 RGB

Related ideas: Racing game , Minimal client. WebGL + CORS should work (test).