iOS: Crash and high RAM spike when using 16384×16384 texture size during textured mesh creation

[zeitlerv]

Description We need very high-resolution textures for our meshes, so we set Texture Size to 16384×16384. However, during textured mesh creation this causes a large RAM spike and often crashes the application. At 8192×8192, the memory spike is much smaller (see screenshot).

As an alternative I tried using Settings → Assembling → Maximum Output Textures with a lower resolution but multiple files, but that approach failed (see linked issue (https://github.com/introlab/rtabmap/issues/1538)).

To Reproduce

1. Launch RTAB-Map.
2. Open Settings → Assembling.
3. Set Texture Size to 16384.
4. Close settings and start a new mapping/mesh session.
5. Perform a scan and proceed to Create Mesh with texturing enabled.
6. Observe RAM usage and application stability.

[matlabbe]

Related comment https://github.com/introlab/rtabmap/issues/1538#issuecomment-2982579454