perf(universe): sort body depth with a stable radix sort, the same order six times faster - #1059
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…ks in a typed array; the same order six times faster
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Change
Every frame the view turns, the universe re-sorted all 3,631 bodies by depth with a comparator and re-ranked them in a map. It was the top script cost on every page. A stable radix sort on the depth's bits now gives the same order, with ranks kept in a typed array.
Evidence and limits
Proves the change: main's and the new depth order, cut from their source and run on the prepared world bodies with ties and -0 added, give identical ranks and z-indices across 2,400 random orientations. One update takes 0.10 ms instead of 0.61 ms. In the Earth and Milky Way replay profiles, the depth order falls from 3.8% of samples to 0.6%.
Clean: renderer universe and node tests, runtime-package tests, renderer typecheck.