Using a single Online Maps for multiple maps

Hi, thanks for the explanation.

I think I want to go with one instance of the map for all the pages.
Each page only shows a static map of a location set by the user.
The location can be changed by the user in another scene, with an interactive OnlineMaps.

So my wish would be to have an invisible OnlineMaps that loads all the location maps slowly in the background when entering this part of the app.

Ideally, when the user enters page 1:
- OnlineMaps sequentially downloads maps for all the pages in the background and renders each to a Texture.
- User can freely scroll to the other pages without any lag due to rendering maps.
- After a few seconds the map pops up on page 1, and after a few more it's ready for page 2 etc.
- At any point, the user can click on one of the maps, to open the second scene with an interactive map, and navigate to a new position. That position will then be replicated on the postcard later when returning.

* It it possible to have OnlineMaps work in a more on-demand manner? So that I can ask for it to download the tiles I need and render to texture?
* And currently when I enable the OnlineMaps component, my app UI starts jerking for half a second. Is it possible to have this downloading smoother and unnoticable?

Thanks!

Hi, I've started looking into this now.

I'm not sure I quite followed your explanation. Not sure how to "Iterate all tiles in a range". What range? Can the tile corners give me that range? Searched through all the code in the plugin for "GetTileCorners" but I couldn't find a similar use-case.

Instead I tried creating an OnlineMaps GameObject with a TextureControl and let it download the maps into textures in the background.

In my test project, I simulate the loading of maps while moving a cube smoothly over the screen to see if any janks are occuring.
And I found that the graphics performance wasn't degraded at all from loading textures, great!

The test code I'm using to feed new Textures into OnlineMaps below works great:

IEnumerator LoadMaps()
{
  for (int i = 0; i < 10; i++)
  {
    Texture2D t = new Texture2D(512, 512, TextureFormat.RGB24, true);
    generatedTextures.Add(t);
  }
  Random.InitState(1234);
  for (int i = 0; i < 10; i++)
  {
    yield return new WaitForSeconds(2.0f);  
    onlineMaps.SetTexture(generatedTextures[i]);
    onlineMaps.SetPosition(15 + Random.Range(-15, 15), 40 + Random.Range(-15, 15));
  }
}

But the problem:
I would really like to make sure that the generated textures don't contain empty tiles because of zoom level. But instead use tiles from a lower zoom level, and scale them up.

The script you recommended in another thread using the OnTileLoaded() callback works great for TilesetControl, but doesn't receive any tile texture at all to the callback when using TextureControl:

OnTileLoaded: '18x131070x100183', Tile texture: ''
OnTileLoaded: '18x131070x100184', Tile texture: ''
OnTileLoaded: '18x131070x100185', Tile texture: ''

Is there a way to ensure this in OnlineMaps Texture mode?

Thanks!

It wasn't difficult to change out the code in
- OnlineMapsThreadManager.ExecuteMainThreadActions() to just invoke a single action per frame, which removed most of the stuttering.

- Also in OnlineMapsCache.OnPreloadTiles(), I had to reduce the time it's allowed to run.
from:   if (Time.realtimeSinceStartup - start > 0.02) return;
to:       if (Time.realtimeSinceStartup - start > 0.004) return;

- I also tried to change the tile size in OnlineMapsUtils.tileSize from 256 to 64 to reduce loading and texture creation even further, but that started spamming NullReferenceExceptions on this line in OnlineMapsCache.LoadTile():
           if (!map.control.resultIsTexture || tempTexture == null)
Apparently "map" is null here.

Ah, you're right. It wasn't the tileSize that caused the errors. It was simply that when I changed tileSize, tiles started loading from network instead of cache. Map loading from network stopped working completely.

The error showed itself when I rewrote ExecuteMainThreadActions to invoke only one action per frame:

            if (mainThreadActions.Count != 0)
            {
                mainThreadActions[0].Invoke();
                mainThreadActions.RemoveAt(0);
            }

If I add the try-catch like in the previous implementation, the error is hidden, and map loading works again:

            if (mainThreadActions.Count != 0)
            {
                try
                {
                    mainThreadActions[0].Invoke();
                }
                catch { }
                mainThreadActions.RemoveAt(0);
            }

But if I Debug.Log() inside the catch { } I see that the error occurs sporadically. Maps are still loaded though and everything works.

But do you know where the error comes from? And is it possible to fix, to avoid Exceptions and improve performance?

System.NullReferenceException: Object reference not set to an instance of an object
  at OnlineMapsCache.LoadTile (OnlineMapsTile tile, System.Byte[] bytes) [0x00009] in \Online maps\Scripts\Cache\OnlineMapsCache.File.cs:205
  at OnlineMapsCache+<>c__DisplayClass40_1.<TryLoadFromFileCache>b__1 () [0x00000] in \Online maps\Scripts\Cache\OnlineMapsCache.File.cs:283
  at OnlineMapsThreadManager.ExecuteMainThreadActions () [0x0001d] in \Online maps\Scripts\Threading\OnlineMapsThreadManager.cs:110

205:        if (!map.control.resultIsTexture || tempTexture == null) // map is null

I think you should be able to see it in your project too, if you remove the try-catch. I tried it in an (almost) empty project with the Tileset example scene.

Sounds great that you'll release a new version!

There's also another problem, zooming with OnlineMapsZoomMode.center:
  1. Move to the top of the map at zoom level around 5.
  2. Zoom out to level 1
  3. Map will be halfway outside the screen
  4. Start dragging map
  5. Map pops into center

I fixed it temporarily in SmoothZoomOnMouseEvents.UpdateZoom(), and 3 other places:

            if (control.zoomMode == OnlineMapsZoomMode.center) control.ZoomOnPoint(z - map.floatZoom, new Vector2(Screen.width * 0.5f, Screen.height * 0.5f)); // PREVIOUSLY: map.floatZoom = z;
            else control.ZoomOnPoint(z - map.floatZoom, inputPosition);

I actually kind of liked the mode where you can be at the edge of the map even when zoomed out. But then it shouldn't snap to the center when starting a drag. That way I can zoom in and out freely without fear changing the position in center zoom mode. Is there a switch to enable that?
I could kind of get it to work by disabling this line in OnlineMaps.SetPosition:
        if (modified) projection.TileToCoordinates(tpx, tpy, zoom, out lng, out lat);
But I didn't really know what I was doing.

Also when looking closer into what happens when zooming, I also found some calls to "Camera.main", in Camera.main.ScreenPointToRay(). Most are using activeCamera.ScreenPointToRay() though. Just thought I would mention it.

Thanks for all the help!