Add polylines with geographic coordinates

[adrian-cojocaru]

Enable adding polylines with geographic coordinates for custom drawables

[github-actions]

Bloaty Results 🐋

Compared to main

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.0% +20.7Ki  +0.0% +6.96Ki    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results/pr-3547-compared-to-main.txt

Compared to d387090 (legacy)

    FILE SIZE        VM SIZE    
 --------------  -------------- 
   +33% +38.1Mi  +448% +26.7Mi    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results/pr-3547-compared-to-legacy.txt

[github-actions]

Benchmark Results ⚡

Benchmark                                                     Time             CPU      Time Old      Time New       CPU Old       CPU New
------------------------------------------------------------------------------------------------------------------------------------------
OVERALL_GEOMEAN                                            +0.0048         +0.0049             0             0             0             0

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/benchmark-results/pr-3547-compared-to-main.txt

[github-actions]

Bloaty Results (iOS) 🐋

Compared to main

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  [ = ]       0  [ = ]       0    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results-ios/pr-3547-compared-to-main.txt

[stefankarschti]

This was left out because the transformation matrixes don't have enough precision at global scale with the standard shader, but it's handled in the Wide Vector.

[stefankarschti]

check out the usage of diff matrixes to enhance precision in wide vector metal shader

maplibre-native/include/mbgl/shaders/mtl/widevector.hpp

Line 59 in 1e78e14

struct Uniforms

[adrian-cojocaru]

This is mostly a backup for platforms/backends that don't have WideVector implementations (yet).

[stefankarschti]

ok, but you should check the results, as the lack of precision makes it really unusable past a certain zoom level.

[stefankarschti]

could we document this limitation, in code comments or other docs?

[adrian-cojocaru]

I'm thinking of moving this bit in the example code (with comments) and removing the line type selection on addPolyline (global) for now.

[adrian-cojocaru]

I've been looking over the different matrices, but only mvpMatrix is used in the shader and this should be the tile matrix (same as the line shader). Is there something else that I'm missing or the extra precision is from the different input types (float3 vs short2)?

[stefankarschti]

indeed, looks like the diff is not used in the final version.
if the geometry is stable at zoom >= 20 then go ahead with the changes