MapLibre-GL-JS problem with MBTile source

[mr-sven]

At the moment I face a problem using MapLibre GL JS and an MBTile source.
The tilejson responds with scheme: tms what is correct I've read because mbtiles are always tms?!?!
It looks like MapLibre GL JS is taking care of that and requests a inverted y axis, but in the mbtiles mod the y axis is inverted again:

martin/mbtiles/src/mbtiles.rs

Line 144 in 00757ee

let y = invert_y_value(z, y);

So I'm getting no tiles for the specified region. If I point maplibe to a modified tilejson with scheme: xyz it will work.

[mr-sven]

As soon as every function in mbtiles mod inverts the y axis the tilejson should respond with xyz.
At the moment I'm searching the location for that.

[nyurik]

Martin's sources are xyz, regardless of the backend. Users (clients) should not know the type of the data backend, especially because multiple backends can be combined. If the data is coming from an mbtiles, Martin will normalize it.

[mr-sven]

Ok, so the tilejson should always return xyz?

[nyurik]

I believe it always does, unless somehow forced, e.g. with a PG SQL comment. From the looks of it, schema is never set from any metadata fields at

martin/mbtiles/src/metadata.rs

Line 119 in 5f28466

while let Some(row) = rows.try_next().await? {

[mr-sven]

yes, that's what I also found and currently I'm modifying the source step by step locate the issue why it responds with tms

[mr-sven]

now it gets worse, I modified the merge_tilejson function to explicit set the scheme and I also logged the scheme of the tilejson object, but the response is tms

[mr-sven]

Ah, do I miss here something?

{

"scheme":"xyz",
"version":"3.15.0",
"filesize":"601583616",
"format":"pbf",
"id":"openmaptiles",
"maskLevel":"8",
"pixel_scale":"256",
"scheme":"tms",
"tilejson":"2.1.0"
}

scheme is twice in the json, how do that work.

[mr-sven]

Ok, the scheme is placed in the other map of the TileJSON object because that the get_metadata function does not take care on that:

martin/mbtiles/src/metadata.rs

Lines 139 to 142 in 5f28466

	_ => {
	let file = &self.filename();
	info!("{file} has an unrecognized metadata value {name}={value}");
	tj.other.insert(name, Value::String(value));

I'm working on a fix.