Spline36 appears to shift the output

[FordPerfect]

I suppose, I should post the follow-up: https://github.com/hrydgard/ppsspp/issues/15566 .
Comments are welcome.

Having both bucubic shaders does feel a bit like cluttering the interface. Does anyone actually prefer Mitchell-Netravali over Catmull-Rom?
For that matter, does anyone prefer Catmull-Rom over Spline36? As Spline36 is heavier, it is expected to be higher quality, but who knows (percieved quality is somewhat subjective, anyway)? For one thing Catmull-Rom makes 1:1 scaling an identity transform (not that it is a typical usecase), but Spline36, AFAICT, does not (and neither does Mitchell-Netravali).