Step 9. The tier split was the work; Django was the easy half.
Tier 1 — the authored scene — is the document, and it is addressed as
independently versioned leaves rather than saved whole, so one vertex drag
cannot clobber a collaborator's keying. `domain/leaf` is the document as
path -> value; `domain/wire` puts it on the wire as transit, because JSON
has neither integer map keys nor keywords and a save would quietly turn
`{0 v}` into `{"0" v}`.
Tier 2 — the dense channel blocks — is content-addressed by a hash over
every input, with the detector version inside every key through the
analysis the block descriptor names. `flow/address`'s `block-knobs` is the
invalidation table, and `address-test` does not trust it: it re-freezes the
take once per knob and asserts the biconditional, that a block's bytes
changed if and only if its key changed. That found `brow-pos` not depending
on `contour-avg` — the brow ring is smoothed, the raise is not.
Tier 3 — frames and audio — is served by the hash of its bytes out of the
same store. A manifest now names frames and carries a URL for each, so the
frame layout stopped being a shared secret between a shell script and a
ClojureScript namespace, and the `?v=` cache-buster went with it: a blob's
name is the hash of its contents, so a stale copy is not a thing that can
happen. The synthetic take's `audio.wav` moved to `static/arthur/` — an
asset the project owns, not an extraction that churns.
The server verifies rather than trusting a name it was handed: it
recomputes every key from the descriptor stored beside it, refuses an
analysis that declares no detector version, and refuses a document naming
blocks it does not hold. It hashes the descriptor TEXT, because JS prints
an integral double as `1` and Python as `1.0`, and a scheme where both ends
re-render the numbers disagrees on the first parameter that happens to be
whole.
Two loose ends from step 8 closed on the way. `pack` no longer takes a
`(track, frame)` predicate whose call sites each re-derived a feature from
an index — every track names the feature it follows, which deleted five
hand-maintained mappings. And `:dev-http` is gone: Django serves the page,
shadow-cljs only builds into the staticfiles tree.
227 CLJS tests, 31 Django tests, green.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Steps 2 and 3 land together because the model revisions in the middle changed
code from both, and splitting them now would invent intermediate states that
never built.
domain/channel value-at across framed/keyed/dense, plus a cursor
domain/node decomposed transform, composition order, time maps
domain/scene topological order, z paths, eval-frame and resolver
clock audio-clocked frame derivation, outside app-db
db/events/subs re-frame arrives; the playhead is document state
ui/player the rAF loop; reads, blits, dispatches (almost) nothing
ui/shell transport
133 tests, 1158 assertions. The scene plays at 30fps against audio, scrubs, and
runs at 1/4x through 4x; verified by driving a real browser over CDP rather than
by assertion.
Two evaluators, on purpose. `eval-frame` is the specification -- allocating,
order-free, obviously correct. `resolver` is what playback uses: cached topo
order and z paths, a cursor per channel, a preallocated point buffer per node.
Both run the same walk, parameterised only by how a channel is read and where
points are written, because two independent implementations of frame evaluation
would drift and the drift would read as a rendering bug rather than as two
functions disagreeing. scene-test asserts they agree frame for frame in forward,
backward and random order.
Deviations and decisions, each with a reason:
- raster/fill-poly! is now a thin wrapper over fill-poly-buf!, which takes a flat
preallocated buffer. ONE scanline fill serves the analysis stages, which speak
{:x :y}, and frame evaluation, which hands over a buffer it owns. The parity
suite still passes pixel-for-pixel, which is what makes the rewrite safe.
- The state mask carries ABSENCE ONLY. An earlier draft gave it a hidden bit too,
per architecture.md's "hidden flag + palette index", and that bit was a dense
[:vis] wearing a different hat -- two mechanisms for one question, which is how
a part ends up hidden by one and shown by the other.
- The palette is a parameter of evaluation, not a global. A node names a TONE;
which ramp that tone is read in belongs to the timeline it sits in.
- :over layers and a symbol :rate THROW rather than being ignored. Neither is
built and nothing can produce one, so this can only fire on data that has run
ahead of the code. A silently dropped override is a hand correction the user
made once, watched fail, and has no reason to trust again.
Three findings the model produced rather than received:
- Presence propagates asymmetrically. An absent transform drops the subtree; an
absent [:geom :pts] drops only that node, because an absent mouth outline has
nothing to draw but the head it hangs off has not moved. That asymmetry is the
reason presence is tracked per channel and not per node.
- Z paths need lexicographic compare, not `compare`, which orders vectors by
count first -- so a cel three levels under "a1" would jump in front of a bare
"a2" and the layer order would mostly work.
- A node stencilled by something that drew nothing is dropped, not drawn
unclipped: an iris floating over the cheek is worse than a missing iris.
docs/ revised alongside, and those revisions are the load-bearing part:
- A scene, a timeline and a symbol are one type. The doc had two structures with
the same fields and never said so. Two axes of nesting are now separated --
parent/child within a timeline is flat with parent pointers, instance nesting
is by reference -- which is why "nestable" and "flat" only sounded
contradictory.
- Palettes are named, live on the project, and are ENABLED on a timeline as a
channel. Absent inherits; present travels with the timeline, so a symbol
authored against :night stays night wherever it is placed. The output index
space is the concatenation of the named ramps, which keeps one buffer and one
flat table and incidentally stops two nodes in different palettes colliding on
a stencil.
- Stabilisation is a channel, not a mode: {s, theta, tx, ty} IS [:xform :*], so
the normalise on/off/per-plate toggle is which of the three channel shapes the
:head node carries. Always measure and always store factored -- smoothing and
velocity-minimum key selection both need the split to exist in storage.
- There is no camera node and none is needed. Placement is a node transform, the
stage clips what hangs off it, and project dimensions are independent of the
footage. `makeXform` is therefore not to be ported: it bakes a cropping
decision into every stored vertex.
- Export is removed. The .take writer was for an Animator Pro render script; the
target is encoding video in the browser, and step 9 now says not to port the
old one.
demo/swarm is 120 shapes on six orbits, entirely dense blocks behind store
handles -- the shape freeze produces at step 5, and the first thing to exercise
that path under load. It plays at 30fps, and bench-test keeps a deliberately
loose floor under it because a performance regression here does not announce
itself: the picture stays correct and merely arrives late.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PDfHGdV39zu6rvgbBTfDaT
Scaffolds frontend/ (shadow-cljs, reagent 1.2.0, re-frame 1.4.3) and ports
everything below the data model, with the JS kept as a numeric oracle.
domain/landmarks index tables, verbatim
domain/ring subsample, offset, simplicity
domain/geom similarity fit, procrustes, moving average
domain/raster indexed scanline fill, stencil, disc, rect
domain/palette the ramp, and the no-sampled-RGB rule
58 tests, 166 assertions. Parity with js/ on the identical 72-frame synthetic
track: fit-similarity, procrustes-mean, fit-residual, moving-average,
smooth-transforms, offset-ring and subsample-slots to 1e-9; the raster
pixel-for-pixel over the whole buffer.
Three deviations from the JS, each for a reason:
- synth.cljs jitters from a SEEDED generator, not Math.random. Parity is only
checkable if both sides can be handed the same track, and a failing assertion
has to be reproducible. `:rand-fn` takes the generator over, so oracle.mjs
stubs js/Math.random and js/ itself stays untouched.
- raster/->rgba replaces toImageData. ImageData is a DOM type and domain/ may
not touch the DOM; returning plain bytes also lets the
no-intermediate-colours assertion run in node. ui/canvas wraps it later.
- offset-ring lives in domain/ring, not domain/geom, per architecture.md: it is
an operation on an ordered traversal, not on a transform.
Step 1's "done" also names the swapped-iris vote, but pairIrises is in
pipeline.js and belongs to step 7. The precondition is asserted instead --
`:swap-iris` really does move both blocks -- so the vote will have a track that
disagrees with it when it arrives.
One finding, recorded in full in the test that measures it: smooth-transforms
buys nothing on the synthetic track. Against jitter-free ground truth, radius 1
helps by 17% on one noise realisation and hurts by 0.5% on another, so its
benefit is within noise; from radius 2 up the cost is unambiguous, and by radius
5 the filter is below the true motion's own high-frequency energy, i.e.
smoothing away performance. The test pins the shape of the knob rather than a
preferred value. This may say more about the synth's jitter being unrealistically
small (+/-0.001 normalised) than about the knob; step 6 settles it on real
footage.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
