Reuse prefetched tiles to avoid empty screen

[alexcristici]

When zooming out if needed tile is not loaded or not in cache it will try to use the prefetched tiles from a higher zoom level.

Before:

Before.MP4

After:

After.MP4

Recordings are from Debug iPhone 6s so the behavior to be more visible, release build is much faster.

Before:

Before.MP4

After:

After.MP4

[github-actions]

Bloaty Results (iOS) 🐋

Compared to main

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.0%    +664  [ = ]       0    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results-ios/pr-2668-compared-to-main.txt

[github-actions]

Bloaty Results 🐋

Compared to main

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.0% +10.8Ki  +0.0% +1.94Ki    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results/pr-2668-compared-to-main.txt

Compared to d387090 (legacy)

    FILE SIZE        VM SIZE    
 --------------  -------------- 
   +27% +31.0Mi  +420% +25.1Mi    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results/pr-2668-compared-to-legacy.txt

[github-actions]

Benchmark Results ⚡

Benchmark                                                     Time             CPU      Time Old      Time New       CPU Old       CPU New
------------------------------------------------------------------------------------------------------------------------------------------
OVERALL_GEOMEAN                                            -0.0137         -0.0135             0             0             0             0

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/benchmark-results/pr-2668-compared-to-main.txt

[louwers]

This test is failing:

[ RUN      ] Map.PrefetchTiles
/home/runner/work/maplibre-native/maplibre-native/source/test/map/prefetch.test.cpp:63: Failure
Expected equality of these values:
  tiles.size()
    Which is: 19
  expected.size()
    Which is: 10
[  FAILED  ] Map.PrefetchTiles (318 ms)

[alexcristici]

This test is failing:

[ RUN      ] Map.PrefetchTiles
/home/runner/work/maplibre-native/maplibre-native/source/test/map/prefetch.test.cpp:63: Failure
Expected equality of these values:
  tiles.size()
    Which is: 19
  expected.size()
    Which is: 10
[  FAILED  ] Map.PrefetchTiles (318 ms)

I will have to update the tests.

[alexcristici]

Tests are passing, PR is ready for review.

[louwers]

In my testing the old tiles stick around too long, which has unexpected visual results, especially when the density of data at a higher zoom level very is different.

Before

Screen.Recording.2024-08-02.at.15.47.11.mov

After

Screen.Recording.2024-08-02.at.15.46.15.mov

[alexcristici]

@louwers Should be fine now. Please check again.

[louwers]

That looks better!

[alexcristici]

pre-commit.ci autofix

[alexcristici]

@louwers Not sure why precommit is failing.

[TimSylvester]

Looks good. Have you tried it in overscaled and wrapped cases? It doesn't look like the new tests consider them.

[alexcristici]

Looks good. Have you tried it in overscaled and wrapped cases? It doesn't look like the new tests consider them.

Yes, overscaled works good. algorithm::updateRenderables function is based on overscaled tile logic.