sortByDistanceToCamera doesn't work for PointLayer

[joric]

maptalks's version and what browser you use?

maptalks-gl v0.105.3
chrome

Issue description

The VectorLayer option sortByDistanceToCamera: true doesn't work for PointLayer (and/or GroupGLLayer).

All image markers in PointLayer render in random depth (or rather, in the add order), it's a big issue.

Tried orderByCamera: true from GroupGLLayer.ts, it doesn't work either.

Tried adding markerAllowOverlap: true, to symbol and collision: true, to layer, the order somehow inverted but still wrong.

Observed with markers that are in the same layer, so it doesn't depend on other layers.

It worked for VectorLayer just perfectly. Do I need another option? Something zBuffer-related, perhaps?

Please provide a reproduction URL (on any jsfiddle like site)

https://joric.github.io/stalker/

[joric]

@fuzhenn please help. That should be implemented already, shouldn't it? I just cannot find an option to enable it.

[joric]

@fuzhenn I think I made it work using sceneConfig property:

    layer = new maptalks.PointLayer(layerName, [], {
      // ...
      sceneConfig: {
        depthFunc: '<=',
      },
    }).addTo(groupLayer);

But it was really confusing that it doesn't work by default. Should be well documented somewhere, it's really one of the first things you expect from the pointLayer.

If you set it on group, it doesn't work, must be set individually for each layer. Multiple layers in group appear to use common z-buffer so markers render with correct depth across all layers. Not sure how to make them explicitly overlap though.

I'm yet to check all the cases like overlapping vector geometry but it was a big step forward and it took 2 weeks to figure out, I discovered it by accident in the Chinese documentation here https://doc.maptalks.com/docs/api/vt/point-layer/