The pixel-art check falls over sporadically, and its follow-up hid it. That one only
asked whether some pixel across the border is blended – but in the failing case the
`nearest` reading is already blurred, so the `linear` one is too, and the check passed
while saying nothing about whether the switch had any effect at all.
It now also demands that the picture actually changed against the `nearest` reading:
the summed colour distance over the five sample points must exceed 150. Measured on the
readings recorded in the note, a working switch drifts 425 and a hung one 0 – and 30
even if every channel were off by two, so the threshold is not brittle against noise.
Exact equality was the first draft and would have gone green on a single wobbling bit.
Both checks now carry `__gm.textureFilter(file)` in their message, so a failure says by
itself whether the model never switched, the switch missed the GPU sampler, or the
pixels were measured wrong.
The cause of the sporadic failure is still unknown; four hypotheses are measured and
ruled out in the note, which is filed with that stated plainly.
root
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