mrview: dixel view on Apple M1

[bjeurissen]

Trying to load a diffusion weighted data set using the dixel view to inspect the raw signal results in a crash on Apple M1.

Is this related to the issues with the pseudo tube rendering reported #2247 (suspected to be the consequence of using geometry shaders on Apple M1)?

[Lestropie]

Yep, the dixel render uses a geometry shader. The "blocky" appearance is achieved by calculating the normal on a per-triangle basis rather than a per-vertex basis. Achieving the same without a geometry shader, i.e. doing it instead in the vertex shader, would require a lot of vertex duplication.

[bjeurissen]

Just noticed that disabling slab visualization when rendering fixels also results in a crash.

[bjeurissen]

Using Big Sur 11.5 and 11.6, I can no longer reproduce this issue (dixel view crash).