Field note
Impeller shadows on a mid-tier GPU
2026-03-02 · Mei-Ling Tsao
Simulators still lie about blend modes. When our cohort shipped a nutrition dashboard, gradients looked velvety on desktop builds yet banded on a Snapdragon 695 class phone. We paused feature work and scheduled a weekly “GPU honesty hour” where builds rotate through five loaner devices.
The fix was not a single shader tweak. We split elevation into two layers—one for structure, one for lighting—and capped blur radii per device tier. Documenting those caps in the repo saved the next team from rediscovering the same cliff.
If you teach Flutter, bake device variance into the rubric. A screenshot from a flagship phone is a story; a tray of mid-tier devices is evidence.