DISPLAY_RATIO_DEEP 1.0 -> 2.0, so a viewport-fit request at District/
Quarter/Block/Chunk asks for ~4x fewer gridunits (1920x1080: ~2.07M
cells -> ~518K) and the server-side derive cost falls with it. Texel-
exactness is preserved — the ratio stays a whole number of screen px
per gridunit, so every source texel still lands on whole pixels; only
the block size changes. Non-integer ratios are not an option here:
they reintroduce exactly the sub-pixel blur D-255's texel-exactness
exists to prevent.
Judged live by Jeroen against the 1x1 build (pair session): the deep
rungs read as crisp larger pixels rather than blur, and the speedup is
substantial. Looks were the gate.
Both transport tests that pinned the old literal now assert the
RELATIONSHIP instead — deep rungs share the constant, viewport-fit
divides by it — plus a new guard that the ratio stays whole, so the
value remains tunable without editing tests that are not about it.
Co-Authored-By: Claude <noreply@anthropic.com>
jpmschweitzerandClaude
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