The backface culling in rendering those assumes they are all oriented clockwise, but OSM data doesn't guarantee a specific winding order. This mostly worked so far as the previously used polygon clipping library ended up normalizing the winding order as an (unwanted) side-effect. Since that has been fixed the issue became visible here with building walls sometimes rendered the wrong way around.
Torsten Rahn (d3c923f7) at 01 Feb 20:20
Normalize polygon winding order for 3D buildings
Thanks a lot Volker for the quick fix!!!
This is superseded by the Tirex-based generator for z >= 11 and is only used for the Natural Earth based low-z tiles now.
Torsten Rahn (d06051cf) at 18 Jan 20:28
Remove the no longer used high-z mbtile OSM raw data generator
Torsten Rahn (d06051cf) at 18 Jan 20:28
Remove the no longer used high-z mbtile OSM raw data generator
... and 2 more commits
This is superseded by the Tirex-based generator for z >= 11 and is only used for the Natural Earth based low-z tiles now.
So what is being used for the Natural Earth based low-z tiles after applying this patch?
On level 17 we want data as verbatim as possible, and with the boundary markers removed there is actually nothing this does anymore for z17 that we need/want.
Simplify it's implementation accordingly.
Torsten Rahn (15c862bb) at 18 Jan 19:55
Only run NodeReducer on zoom levels where we actually need it
Torsten Rahn (15c862bb) at 18 Jan 19:54
Only run NodeReducer on zoom levels where we actually need it
... and 21 more commits
Torsten Rahn (2d20830b) at 18 Jan 19:53
Skip clipping of inner rings not included in the tile at all
Torsten Rahn (2d20830b) at 18 Jan 19:52
Skip clipping of inner rings not included in the tile at all
... and 20 more commits
Torsten Rahn (7d9e602f) at 18 Jan 19:52
Remove the no longer used high-z mbtile OSM raw data generator
... and 20 more commits
Good catch, please submit a patch.
This is unused and despite several attempts I haven't found a way to make use of this in geometry reassembly. Given this is based on the already clipped and reduced paths it also seems like this cannot possibly contain additional information for reassembly anyway.
Torsten Rahn (46b72593) at 18 Dec 22:24
Remove the border point annotations
This avoids the expensive clipping process and results in slightly smaller tiles (no synthetic id and the real id stored delta encoded rather than as tag value string).
Most importantly though, it passes OSM data through unaltered, unlike our current clipping code which can reorder vertices. While that's not such a big deal for polygons, that can significantly alter the semantics of directional lines. That remains to be fixed for the clipped cases though.
Torsten Rahn (7227009d) at 18 Dec 22:22
Don't run elements entirely contained inside a tile through clipping