Sometimes, if timed correctly (and unfortunately), it is possible to end up with a completely blank mesh for a capture, even if there is supposed to be a mesh

[himanshunaidu]

The segmented meshes that are present as realitykit anchors seem to sporadically disappear for very short (sub-second) periods.
But if the capture button is clicked in that duration, the AnnotationView opens with empty meshes.
(This is extra weird, because we do have checks to prevent the AnnotationView from appearing if the meshes are not present, need to check further on this)

[himanshunaidu]

Checking if captureData.captureMeshDataResults.segmentedMesh.totalVertexCount is aligned with the actual total Vertex count

[himanshunaidu]

The captureData.captureMeshDataResults.segmentedMesh.totalVertexCount seems to be in sync.
As it turns out, in such situations, the totalVertexCount ends up being so low that we see no mesh (e.g. 3 in last trial).

Need to check why this happens periodically.

[himanshunaidu]

Possible Cause: MeshGPUSnapshot.snapshotAnchors method may be culling briefly unseen anchors too aggressively.

[himanshunaidu]

Confirmed cause. A low generation threshold is causing aggressive culling of anchors that are not updated.

We can presumably keep this value high because the segmentation-based filtering takes care of removing polygons that are no longer relevant.
However, for performance reasons, we don't want to keep it too high, as the filtering function will have to go through too many anchors.

[himanshunaidu]

A better filtering logic would be to verify if the anchor is still within view.