Performance degradation with large point clouds and show condition on M1 Mac

[ulrichson]

Hello!

I observed a performance degradation when rendering large points clouds that use the conditional show attribute. I'm certain that the performance was much better, in a project I'm using such a technique to filter for attributes from the tileset's batch table and now the framerate drops a lot when the filters are applied. Maybe it only affects macOS / arm architecture — on a Linux / Intel workstation with NVIDIA GPU it works fine.

A quick performance monitoring in the dev tools showed that readPixels consumes a lot of time which is called for scene picking. Is there a way to turn off picking for Cesium3DTileset ? That might help in my case.

I can reproduce this in a sandcastle with the Melbourne point cloud, and you can see the framerate drops from ~100 fps to ~10 fps when zooming in:

https://user-images.githubusercontent.com/449600/236436953-c1d84f1b-3a67-4a1e-a663-8de8214e834a.mov

Sandcastle example: https://sandcastle.cesium.com/#c=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

Browser: Google Chrome Version 113.0.5672.63 (Official Build) (arm64)

But similar experience with Safari / Firefox

Operating System: macOS 13.3.1 (a) on M1 Max