Offline map support on public branch for testing

[brnkhy]

Hey everyone!
I have been working on offline map support (https://docs.mapbox.com/help/troubleshooting/mobile-offline/) for a while now and wanted to let you know it's on a public branch for testing at the moment.

You can find it here; https://github.com/mapbox/mapbox-unity-sdk/tree/offlineMaps

And usage goes something like this;

 var region = new OfflineRegion(
            MapName,
            _minLatLng,
            _maxLatLng,
            _minZoom,
            _maxZoom,
            elevationTilesetId,
            imageryTilesetId,
            vectorTilesetId);
var response = MapboxAccess.Instance.OfflineManager.CreateOfflineMap(region.Name, region);

This will download and cache all tiles in this region in given zoom range. I just pushed it today so there might be bugs and issues of course.
Just to be clear, this doesn't mean you can ship data with your application or anything. This is just a variation of regular ambient cache. Regular ambient cache time out, recycle out etc. Offline maps adds a flag to tiles so they won't time out like regular ambient cache tiles. So it ensures those tiles will be in the cache.

In example, let's say you're building a hiking app where people go off grid frequently to hike. You can let them predownload and cache their hiking area in advance, at their home when they have connectivity for example. SDK will ensure cached tiles will not be removed/recycled/deleted so when they go hiking and don't have connection, their tile data will still be in the cache.

This feature also comes with a lot of changes in Sqlite management so please let me know if you notice any bugs and/or performance issues regarding data in general.

[brnkhy]

for anyone trying this out, please let me know if you run into troubles, it's super beta so there will be bugs but I want to finish this asap so any fixes to this will be priority for me 🙏

[Markovicho]

first note:

OfflineMapDemoController.cs
remove using directive for:

using UnityEditor.Rendering.LookDev;

it seems like it's not used and will throw errors if you are not using the right pipeline:
Assets\Mapbox\Examples\9_OfflineMap\Scripts\OfflineMapDemoController.cs(7,29): error CS0234: The type or namespace name 'LookDev' does not exist in the namespace 'UnityEditor.Rendering' (are you missing an assembly reference?)

by the way thx for the afford. This feature is pretty important for a lot of showcases. Looking forward to check this out

Postscript:

Running on Unity 2019.4.5f LTS on hitting play will result in those errors. It's running on a german system which could possibly cause some formatting/encoding issues (?)

[brnkhy]

Hey @Markovicho ,
Removed the using directive, I have no idea it was there really. Thanks!

Second issue is happening because your existing old SQLite table doesn't work with the new offline maps code. If you use Mapbox -> Clear File Cache from the top menu, it'll delete the existing file and recreate it using new system. Then you shouldn't get the error.

[Markovicho]

Thx! clearing the file cache worked.

postscript:

Building for Android will run into another unused using directive:

CachingWebFileSource.cs ==> using Unity.UNetWeaver

using Unity.UNetWeaver;
causing:
Assets\Mapbox\Core\mapbox-sdk-cs\Platform\Cache\CachingWebFileSource.cs(1,13): error CS0234: The type or namespace name 'UNetWeaver' does not exist in the namespace 'Unity' (are you missing an assembly reference?)

Test on PC:

Configuration:

minZoom: 10
maxZoom: 18

Zoom while Downloading: 16

After the download completed i started to zoom out/in. But only zoomLevel 15+16 seems to work offline oO

I attached a videocapture. there is a little textfield which is showing the current zoomLevel for debug purposes

https://drive.google.com/file/d/1kGao-LXjOX_Sao7f_dcpvcrX1MgdVlgk/view?usp=sharing

[brnkhy]

@Markovicho I'm not sure what's up with those unused directives, great catch!

I'll check the zoom thing but I think it might be something about overzooming (16+ levels). I can't remember for sure now but I might intentionally or not might have capped it at z16. I'll check and update asap.
Thanks for the video by the way, it's great to see it's working well otherwise!

[brnkhy]

@Markovicho I think I fixed the zoom issue. The problem was with the demo scene, it used satellite imagery but sample code downloaded streets imagery so when you went offline, it wasn't able to find different zoom levels of satellite. Somehow, z15-16 was cached though, probably with regular ambient caching.

Also found and fixed a bug with cache expiration date. Thanks a lot!

[Markovicho]

This seems to be solved and is working now as expected :-)
(Tested on Windows and Android 11)

How is the feature behaving on entering the following situations:

• Display standby : ==> Unity-Application will go to sleep...
• Switching to another application ==> Unity-App will go to sleep as well here ...

This could be an interesting point regarding larger downloads or slow internet connections. I assume it would be a large task to outsource this functionality into an native plugin to avoid pausing the download (right ?)
Otherwise we need to find some way to keep the user in the foreground application while the download is running (UX-Design needs to be aware of that point)

[brnkhy]

@Markovicho awesome, thanks a lot with the help, I really appreciate it! As I said I want to get this done as soon as possible.

I'm afraid I have no idea about the issue you described though. I don't do mobile stuff much so I'm not sure how it works but I suspect OS freezes the app when it's in the background? Or doing tricky something in the background without app developers knowledge might not be preferable either. Either way I think it's safer to leave that to app developer. I'm not sure but as far as I know other Mapbox SDKs doesn't do this either right?

[Markovicho]

Like you said no matter if you're using Android or iOS, the application will freeze completely. The only way to keep functionality active in this case is to write an separate native plugin for both plattforms which will continue the tasks while the unity app is freezed. Maybe thats even more work than the current solution itself.
As long as the download will continue correctly after returning to the app thats not a big deal and more an question of the app design.
Anyways this feature is such a big improvement for the unity sdk. thx in advance !!

[raggnic]

Nice ! Is it ok with the mapbox data licence tough?