3dtours
166a677590
The ramp was a0..a4 with the pixel's base interpolated straight between them. A segment meets its neighbour at an ANGLE, and the second derivative of a tone curve is what a gradient reads as a band — so a knob left a line across the mid-tones, worst exactly where it was reported: BLACK +100 put its whole lift inside 0.25 and the stretch from 0.25 up came back identical to the untouched frame (the "transition stays grey" it was reported for), and HIGHLIGHT -100 folded a seam into 0.747, between the highlights it pulled and the shadow it left under them. Measured on a 1024-step luma wedge through the exported pass, second difference through a ±1% box: BLACK +100 read 105 at 0.030 against 0.000 from 0.25 up, HIGHLIGHT -100 read 72 at 0.747. Step of the first derivative across the knots: 0.955 at 0.25 and 1.146 at 0.75 — the curve arrived folded, and 1.146 is a sign flip, not a bend. So each knob is now a BUMP on the identity, peaking on its own knot — BLACK on 0.00, SHADOW on 0.25, HIGHLIGHT on 0.75, WHITE on 1.00 — with the kernel (1-u^2)^2 over a half-width (a half of the ramp for the two ends, whose knots ARE the ends, a quarter for the two heads). Level at u = 0, so a knot moves without a fold at its own top; level at u = 1, so a move lands on the identity and on its neighbour without an angle; C1 everywhere between. The two bumps of a half meet on 0.50 both on zero, which is the same fixed midpoint as before, and DR still moves the same knots (0.12 on the toe, 0.18 on the head, half of each on the heads beside them). A sum of bumps can overshoot where two steep sides land on one stretch — past a slope of 1 the curve runs BACKWARDS, a worse band than the seams this replaces, and it is reachable: DR alone was under it, BLACK and SHADOW +100 together were not (unguarded min slope -0.0141). The guard reads each pair at its own steepest points, 8/(3*sqrt(3))/w per unit amplitude (TONE_BUMP_SLOPE_HALF 3.0792, TONE_BUMP_SLOPE_QUARTER 6.1584), holds the two under one and gives them up together past it. A single knob never reaches it (a full BLACK is 0.77, a full SHADOW 0.77), so every slider keeps its whole travel; the worst case is DR at full, which gives up a tenth of its head roll (0.18 -> 0.8376 on the head), and BLACK with SHADOW both at +100, which arrive at 0.65 of their own lift instead of folding. Guarded, the sweep over five levels of all four knobs and DR reads a min slope of +0.0183 and a max of 1.9937, with the largest slope jump 0.00005. After: the same wedge, the same pass. The knot steps are 0.096 at 0.25 and 0.478 at 0.75, with no sign flip — C1 across the knot instead of a fold. BLACK +100 now carries the rework out of its own quarter: +0.139 at 0.25, +0.101 at 0.30, +0.033 at 0.40, 0.000 at 0.50, where it used to read 0.000 from 0.25 all the way up. HIGHLIGHT -100 keeps its lift (-0.126 peak against -0.121 before) and spends it over the quarter instead of into a line. Every knob on zero is the identity to the last bit — the pass also runs for the stock split tones and for DR alone — and 0.50 is still the one value no knob moves. Checks: tone-base-check.mjs now runs the bump and the guard as arithmetic beside the shader (with the negative control: the unguarded pair still folds, the guard is what stops it). highlight-knee-check.mjs reads the kernel and the two slope constants off the source, pins the four amplitudes and the guard, and sweeps the travel of every knob as before. All ten checks that run without a browser pass, build clean. Skipped: the guard's ceiling is a constant, not a search for the widest travel that still clears a band we cannot see. Add when a frame shows a band the deflections in hand cannot explain.
RecipesCam
RecipesCam is a camera and photo-editing app built around recipes — reusable
looks that carry a film simulation plus a full set of adjustments. You shoot or
open a photo, dial in a look, and keep it as a recipe you can apply again, share
as a .recipe file, or save to your account.
It ships twice from one repository: a React Native (Expo) app for iOS and
Android, and a self-contained web build under docker/ that runs the same
render pipeline in the browser.
What it does
- Shoot with a recipe applied. Live viewfinder, GPS-tagged captures, and the recipe baked into the saved file.
- Film simulations. Built-in looks — PROVIPES, VELVIPES, CLASSIC CHRIPES, CLASSIC NEGIPES, ASTIPES, ETERNIPES, ACRIPES, B&W HIGH CONTRAST and the LC STREETLIFE pair — each with its own grain and tone curve.
- The full adjustment set. Exposure, contrast, highlights and shadows, saturation, colour temperature, clarity, grain, and an HSL mixer with a colour picker that samples straight off the photo.
- Geometry. Crop to a fixed ratio or free-form, quarter turns, and a straighten ruler, plus printed frames (classic border, retro instant, wall frame portrait/landscape).
- Finishing. Watermark and GPS stamp, EXIF carried through the export, JPEG written with a proper 300 DPI JFIF header.
- On-device upscaling. A Real-ESRGAN pass runs locally when an export asks for more pixels than the source has — no server sees the photo.
- Recipes. Save, favourite, export and import
.recipefiles; the web build keeps them in your account, the phone build also keeps them on device.
The two builds
| Build | Where | Stack |
|---|---|---|
| iOS / Android | repo root | Expo + React Native, @shopify/react-native-skia for the render pipeline, NativeWind for styling |
| Web | docker/ |
Vite + React, CanvasKit (canvaskit-wasm) for the same pipeline, Fastify + SQLite API for accounts and recipes |
The render engine is shared by design: the web build compiles the app's own
src/utils/* and type definitions unchanged, with @shopify/react-native-skia
aliased to a CanvasKit shim (docker/frontend/src/engine/skiaShim.ts). A look
looks the same on both because it is the same code.
Running the web build
cd docker
cp .env.example .env
docker compose up -d --build
# → http://localhost:8090
Photos never leave the browser: grading, framing, watermarking and JPEG
encoding all run in the visitor's tab; the API only stores accounts and recipe
JSON. See docker/README.md for the layout and the proxy setup.
Running the app
npm install
npx expo start # Expo Go / dev client
npx expo run:android # or run:ios for a native build
Repository layout
App.tsx, src/ the Expo app: screens, tool rail, viewfinder, shaders
docker/ the web build (frontend + API + compose file)
frontend/shared/ vendored copies of the app's types and utils
frontend/src/engine/ CanvasKit shim, export engine, super-resolution
docs/ privacy policy
THIRD_PARTY_NOTICES.md licences of the bundled fonts, models and libraries
Licence
See LICENSE and THIRD_PARTY_NOTICES.md.