glTF 2.0 - Brdf look up texture fails on Samsung Galaxy S6 edge

[lilleyse]

On a Samsung Galaxy S6 edge BrdfLutGenerator.js (called by Model) is crashing Cesium. It's hard to tell if this is a shader compilation bug or something with the draw command execution - but it all looks ok at a quick glance.

https://groups.google.com/forum/#!topic/cesium-dev/BbHs7YRg1DA

[mramato]

We've ran into plenty of problems with the Galaxy in the past (most related to the Mali GPU), one thing that comes to mind is #4563 (floating point textures). But I assume that doesn't apply here.

It would be interesting to try to reproduce this using a WebGL 2.0 context. Since WebGL 2.0 has more features built-in, some of the shenanigans that Android does on a per-GPU basis doesn't happen.

Galaxy S6 has a Mali-T760MP8 so it's possible this occurs on other devices as well.

[kalmykov]

We (flightradar24.com) have now collected some cesium crash stats about different devices; so far we found out that reverting to cesium 1.36 have helped to reduce number of crashes to zero for at least two Mali-T720MP2 devices - Samsung Galaxy A7 (2016) and Samsung Galaxy A5 (2016). Unfortunately we don't have actual devices on hand, so we can't actually confirm that its caused by exact same issue. We also have some reports about that devices with Mali-T720MP3 are crashing.

[hpinkos]

Thanks for the info @kalmykov! That should be helpful for debugging this