The fused pass stops at "linear working values" when a sharpener, a
blur or a repair follows, and the detail passes convolve what it hands
on. Until now it handed on the rendering: the base curve, and since the
last commit the view transform, ran before the store. So every kernel
worked on display-referred values while its comments promised the
opposite — D19's second finding.
A fused pass composed for a detail stage now stops before the view
transform, and carries a second shader, `ComposedShader::view`, composed
from the same inputs. It runs the same prologue, for the positions a
fragment reads (a film's grain seeds from `source_px`) and the corners
it blacks out, takes its colour from the detail stage's result bound
where the sample cache would be, and runs the view transform, the
output transform and the mask reveal. `render_detailed` dispatches it
after the last detail pass, in the same encoder.
So no detail pass encodes any more. Every pass writes an intermediate,
the last one included, which retires three things that existed only to
make the last pass encode: `writes_output` and the runner's second
layout, the body-less resolve pass for an active kernel with nothing to
draw at this scale, and capture sharpening's pass-through, which now
emits no pass at all. An empty chain is a whole render: the view pass
reads the fused result directly. The detail stage no longer takes an
output space either, so `compose_detail_for` folds into
`compose_detail` and the space is named once, on the fused half.
The cost is one full-render read and write per frame when a detail
stage exists, and a third intermediate for a one-pass chain.
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>
dtourolle
