Tracker: COPC tiled loader

[jo-chemla]

• COPC = Cloud Optimized PointCloud (basically the las/laz equivalent to COG for pointclouds instead of geotiffs)

Gradually adding support for COPC is a background effort in loaders.gl. It is partly aligned with a parallel effort to add PoTree 2.0 support.

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• [x] Create new COPC module, with rough initial COPCSource implementation @ibgreen #3030
• [ ] Creeat a new Tile3DSource type interface and update COPCSource to implement it.
• [ ] Update 3D Tile (pointcloud) rendering code to work with Tile3DSource instances such as COPCSource.

• [ ] Create website example rendering a public COPC source.

  Feedback (still WIP) on the COPC.js repo repo - CC @connormanning and hobu team. P0/P1 asks

• [ ] Drop cross-fetch dependency
  • Dependencies, especially node related ones, are causes for concern, bundle size issues, bundling complications with different bundlers etc.
  • All LTS versions of Node.js supports fetch natively now.
  • Big applications already have a fetch strategy and want to control fetching.
  • Recommend letting application supply its own fetch function rather than make the choice for it.
• [ ] Update laz-perf dependency?.
  • Why 0.0.5 and not the latest, 0.0.6?

P2 asks - General recommendations (make the copc.js library more user and contributor friendly)

• [ ] Replace "barrel exports" with cherry-picked exports.
  • P1 - Hard to see what API is actually being exported when everything is just wildcard exported.
  • P2 - Bundler builders are raising concerns see e.g. https://blog.coderspirit.xyz/blog/2022/11/06/export-barrels-considered-harmful etc.
• [ ] Add TSDoc style comments
  • There is basically not a single comment in the code base
  • /** */ style comments on all exported types, functions, members are picked up by vscode "intellisense" and visible when hovering

• [ ] base-hierarchy.ts seems to be at the core of the API, move it out of its hiding place in the utils folder.

  Original ticket:

• Following comment by @hobu here, it would be nice if loaders.gl could implement a COPC tiled loader.
• Similar to how the OGC 3D Tiles loader works, with points coordinates being expressed in an arbitrary CRS (Coordinate Reference System) usually described by a proj4 string.

[connormanning]

For some additional info, copc.js provides what I'd call "primitives" for dealing with LAS/LAZ/COPC data: header/VLR parsing, hierarchy reading, fetching a COPC node slice (with API for fetching the laszip-compressed block, or decompressed to LAS, or providing a view with getters for each attribute including extra-bytes). Determining what to fetch, caching, running decompression in a web worker, etc, are left up to you.

See the PRs for COPC support in potree and itowns for examples of copc.js usage in the context of adding a COPC loader to a downstream rendering project.

[ibgreen]

@connormanning I made a fleeting attempt at integrating your COPC code maybe 6 months ago but it had bundling issues as it was doing dynamic imports of node specific libraries (fs?) or some such.

Also loaders.gl has its own LASLoader module which is older and I would prefer to update that to align with the COPC LASLoader implementation but didn't immediately see how to separate the code in COPC.

By your description, sounds like your primitive system might be just what is needed to make your code fit into the loaders.gl model.

If we were able to pair up for an hour or so, perhaps we could make short work of it? email me if interested.

[misteryyy]

Hello guys, have you mange to make some progress on this topic? @connormanning @ibgreen