[flame_tiled] Null check on tileData fails for infinite maps

[benni-tec]

Current bug behavior

A null check operator exception is thrown when trying to load (cache) infinite tiled maps

Expected behavior

The map is loaded in chunks or the chunks are consoladated

Steps to reproduce

Simply use an infinite map.

Flutter doctor output

[√] Flutter (Channel stable, 3.13.9, on Microsoft Windows [Version 10.0.22621.2428], locale de-DE)
    • Flutter version 3.13.9 on channel stable at C:\Users\xxxxx\Coding\_sdks\flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision d211f42860 (3 weeks ago), 2023-10-25 13:42:25 -0700
    • Engine revision 0545f8705d
    • Dart version 3.1.5
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[√] Windows Version (Installed version of Windows is version 10 or higher)

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    • Visual Studio Community 2022 version 17.7.34202.233
    • Windows 10 SDK version 10.0.22621.0

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[√] Connected device (3 available)
    • Windows (desktop) • windows • windows-x64    • Microsoft Windows [Version 10.0.22621.2428]
    • Chrome (web)      • chrome  • web-javascript • Google Chrome 119.0.6045.124
    • Edge (web)        • edge    • web-javascript • Microsoft Edge 119.0.2151.58

[√] Network resources
    • All expected network resources are available.

! Doctor found issues in 2 categories.

More environment information

• Flame version: 1.2.0
• flame_tiled version: 1.14.1
• Platform affected: all

Log information

ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Null check operator used on a null value
#0      OrthogonalTileLayer.cacheTiles (package:flame_tiled/src/renderable_layers/tile_layers/orthogonal_tile_layer.dart:25:36)
#1      FlameTileLayer.refreshCache (package:flame_tiled/src/renderable_layers/tile_layers/tile_layer.dart:181:5)
#2      RenderableTiledMap._refreshCache (package:flame_tiled/src/renderable_tile_map.dart:365:13)
#3      new RenderableTiledMap (package:flame_tiled/src/renderable_tile_map.dart:64:5)
#4      RenderableTiledMap.fromTiledMap (package:flame_tiled/src/renderable_tile_map.dart:300:12)

More information

This bug is caused because (as far as I can see all) FlameTileLayer's force-unwrap layer.tileData however with the current tiled implementation this can be null if the map is infinite and therefore split into chunks.

I see two possible solutions:

1. Aggregate all chunks into a single matrix (this would be sufficient for my use case) however with very large maps this can lead to performance issues
2. Implement some mechanism to only render visible chunks and scope the cache/rendering appropriately. This seems like it would require quite a lot of work.

Since finite maps are fine for my use case I probably won't be able to contribute a PR to this!
For the time being I think a warning in the docs that infinite maps are not support would be appropriate!
(I didn't find one so far, I hope I didn't miss it 😅)

[ufrshubham]

Yeah, probably the quickest way to avoid confusion on user side will be to add an assert for infinite maps.