A road section disappears on lower zooms

[pastk]

https://www.openstreetmap.org/way/172544089#map=15/48.10010/37.94158
Its highway=secondary so should be visible from z10-.

But the section disappears on z12 and earlier (Android device):

What's weird in that on the linux desktop its rendered on z12, but is absent on z10-11 still (the maps are the same of course)

So it could be a bug of the lines simplification algo in the generator (produces an invalid result) or a rendering bug in the drape engine.

@vng FYI

[pastk]

Looks like a bug of the extra run-time simplification (ref ApplyLineFeatureGeometry::operator()).

The way is almost circular (the start and the end are very close to each other). So at some point the algo decides to make a short-cut between them and skip all other points of the spline :)

The affected zoom level is different for various devices because they have different dpi, which affects the simplification thresholds.

IMO this run-time simplification is redundant and should be dropped.

• related to [drape] Optimize Spline direction/length calculations. #6122