A clone gets the texture right and the level wrong. Dust on a gradient sky
is copied from a patch a little lighter than the hole it fills, and the
repair reads as a disc even though every grain in it is correct — which is
why FR-DEV-8 asks for heal and not only for clone.
Heal adds the membrane: the difference between the two neighbourhoods,
sampled at twenty-four points around the rim and interpolated across the
disc by inverse square distance. Solving the Poisson problem properly is
tens of Jacobi iterations, and an iteration here is a dispatch — sixty
dispatches to remove a dust spot is not a frame budget. The closed form
costs one loop over the rim, no state, and no second pass.
The spec called for mean-value weights; inverse squares are two
transcendentals per sample cheaper and agree wherever the boundary
difference varies smoothly, which is every repair anyone makes. What
decides whether that trade holds is the measurement, so the measurement is
the test: on a ramp steep enough to leave a clone wrong by 38 levels out
of 255, the heal is wrong by 0. docs/spot-removal.md §6.1 records what
shipped and what it would take to go back.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
A spot set now composes detail passes of its own, one per round, and they
go ahead of every operation's kernel. That placement is the decision worth
recording: a sharpening pass reads a neighbourhood, so sharpening a dust
mark before removing it smears its edge into pixels the repair's disc does
not cover, and what survives is a faint over-sharpened ring around an
otherwise perfect patch. It also disagrees with ARCH §5.2, which draws
spot removal after clarity — docs/spot-removal.md §5.1 is where that is
argued out.
Every length reaching the shader is in render pixels, converted here where
the framing is in scope. Both the centre and the source go through
`Framing::output_at` — the same map the fused pass applies to every pixel
— so a rotated photograph rotates the offset with no trigonometry, and the
radius is found by mapping a point one radius above the centre and
measuring, rather than by multiplying by a ratio this function has no
business knowing about. The tests turn and crop the frame and expect the
mark to stay gone, which is the property that arrangement buys.
compose_full now takes the spot set, because a photograph with a repair
and no sharpening still has a detail stage: a fused pass that encoded its
own output there would quantise twice and bind to a texture of the wrong
format. compose_detail_for takes the source size for the same kind of
reason — a RenderScale describes the region on screen, and a spot is
stored against the photograph.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
dtourolleandClaude Opus 5