Earth to OBJ file downloader
# tested with node@8.15.0, npm@6.4.1
npm install
node index.js [octant] [max_level] [[--dump-json]] [[--dump-raw]]
# dump textured obj (octant from example.jpg)
node index.js 20527061605273514 20
# prevents 3d viewers like blender from jittering
# produces scaled + moved model.2.obj from model.obj
bash scale_move_obj.sh
# dump json and raw data
node index.js 20527061605273514 20 --dump-json --dump-raw
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).
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.