Lab Plugin

The experiment kernel for Clayground Labs: turns any sandbox into an interactive, deterministic, agent-verifiable experimentation space.

Components

Lab (singleton) — registry connecting everything; agents read/write parameters via Lab.p(name) / Lab.set(name, value) and fetch Lab.labInfo() through the inspector’s eval action.
Parameter — named, ranged tunable; bind your system to value.
Probe — named observable sampled on a fixed sim-time grid.
SimClock — seeded deterministic clock; with a world attached, sim time advances with the physics steps (exact under the inspector’s time/step action); seeded random()/randomRange() are the only randomness a lab may use.
ParamPanel — auto-generated slider panel for all parameters. Rows are Tab-reachable and arrow-operable, with a visible focus ring.
Plot2D — live autoscaled strip chart of probes. Pass probes for a fixed set, or series: [{probe, label, color, style, sigmaProbe}] when the plotted set is built at runtime: the lab then owns naming and colouring, an empty array draws placeholder instead of every probe, and legend entries become clickable (seriesClicked) so the user can drop a curve where it is named. style: "scatter" leaves discrete measurements unjoined, sigmaProbe fills a translucent ±σ band behind a curve, and hovering the chart reads every visible series back at the nearest sample.
DataRecorder — probes to a run record (record.js): lab, scenario, seed, every parameter, the per-probe series with their summaries and the command that regenerates it, no wall clock anywhere - so two runs of one seed are byte-identical and a paper can cite the file by id. A .csv destination still writes the flat table, but a CSV carries no provenance and so cannot be cited. Always set an explicit destination (a relative default once littered the repo root).
LabTheme / ThemeSwitch / ScaleSwitch — every colour, shape, type and spacing token, in a light and a dark palette that swap at runtime, all multiplied by one uiScale factor. The two palettes are counterparts rather than inversions, and the rules that make them so live (and are tested) in palette.js — most importantly LabTheme.inkOn(fill), which every chip and badge must use instead of naming an ink, and LabTheme.step(c, amount), which moves a colour away from the ground in whichever direction the palette has room. The measurement half is tokens.js: seven type roles (fontMicro … fontTitle), six spacing steps (spaceXs … spaceXxl) and LabTheme.px(n) for one-off geometry. node palette.test.js and node tokens.test.js check the relationships, not the values. Two roles are easy to miss: the board has its own (board for the sky, table, sheet, inkSolid for a rim or wall - ink as a lit surface cannot simply invert or it becomes a light source), because a recessed 2D paperDeep well still sinks in the dark while the board’s ordering inverts; and data tokens keep their identity across themes - the paper says “the rose track is GPS” and the legend has to agree in both, so a colour is measured on the dark ground and lifted along its own hue only if it fails to read there. The scale exists because a lab shown on a large external screen had HUD controls nobody could read and nothing to turn: every size in the chrome was a bare pixel literal.
LabPrefs — the three settings that belong to the person rather than to the run: ui.theme, ui.scale, ui.lang. Backed by Clayground.Storage when it is present and by memory when it is not, so a lab that never links the storage plugin still runs — it just forgets on exit.
LabLang / LangSwitch — runtime language switch for a published lab. Whoever owns a vocabulary registers it (LabLang.register(dict) with {lang: {key: text}}), strings are ordinary bindings on LabLang.t(key) / tf(key, ...), and LabLang.num(v, digits) prints numbers in the language’s notation (German gets a decimal comma; Plot2D, BudgetBar and ParamPanel already use it). LabLang.qty(v, unit, digits) adds the quantity layer on top — SI prefixes with the mA↔A, ms↔s and k/M crossovers every lab used to hand-roll (format.js, node format.test.js). Not qsTr: retranslating a live engine is a C++ call on the QQmlEngine, which a lab hosted by the dojo or exported to WASM does not own. Drop LangSwitch in a corner and it offers exactly the registered languages.
Scenario / ScenarioSet — named, scripted situations wiring the scenarios()/applyScenario() inspector convention; applying resets the clock so runs are reproducible.
Flow / FlowStep / Narrator / FlowChip — the guided, narrated walkthrough: verbs-as-data driven through the lab’s own flowActions(), demo/task/watch steps, hint→solve escalation, checkpoint scrubbing. FlowChip is the on-screen offer to be taught, so the lesson is not hidden behind a key nobody knows.
CameraDirector — which shot when, for a lab with a presenter in it: journey (start, destination and subject in one frame, the presenter followed until it lands), twoShot (presenter and the thing pointed at), portrait (level with the face, for explanation), cutaway (one thing alone for a beat, then back), wide. Science-TV grammar written once, composed through OrbitCamera3D.fit() with a safe area for the chrome, so no lab hand-rolls arrival/address hooks and no finger points at something outside the picture. The professor kit’s FlowGuide takes one as director:.

Focus mode

Tab clears the HUD: LabView.focus goes true and the instruments, panels, plot, compass, clock and switches step out of the way, leaving the scene and - while a flow runs - the Narrator. It is for studying a scene when nothing is being changed or measured. Most of it is automatic: anything built on LabPanel fades on its own, as do the kernel’s own pieces. A lab only wires what it built itself (a scrim, a button declared beside a panel rather than inside it) with visible: !LabView.focus, and a panel that must survive focus mode sets hideOnFocus: false. LabPanel uses opacity and enabled rather than visible, because labs bind visible on their own panels constantly and a component assigning it would be silently overwritten by exactly the labs that use it most. The alarm banner deliberately does not hide - a short circuit outranks whatever you were looking at.

The board — what a build lab is made of

A lab that places typed parts on a grid, wires their pads and solves the result owns none of that mechanism any more. The domain kit hands over a part spec (spec[type] = { terminals, half, actuator, fields, rows, watch }, see board.js), a solver and a part visual; the kernel does the rest. board.js is pure JS (node board.test.js), tests/tst_board.qml drives the store and the gesture with no GPU.

Board — the store: parts, wires, rev, hit test, keep-out, the mutations, batching, state()/load(), an optional router; changed is where the domain re-solves.
BoardInput — the mouse: wire pads, select and drag, tap a wire, the two-step actuator (operate), eraser, the right-click cancel chain; the camera and the instrument belt are asked first, always. A part’s state belongs on its selection card (a resistor’s ohms, a gate’s function, a switch’s on/off), which is also the only channel that survives having no pointer on a touch screen; operating a part in the scene is a shortcut gated on selection - the part you picked is the part that responds - so a click during building flips nothing and no mode has to be remembered. An actuator region comes first in the hit test (actuatorHalf(type)), has its own gesture (no selection, no drag, fires on release) and three signals that agree on one predicate: a pointing-hand cursor, the lever lightening (never recolouring what already carries state), and a hint-bar line naming what the click will do. electronics-101’s switch was the cautionary tale: its pads reached inward and left a few pixels in the middle as the only place a click flipped it, which read as a bug in wiring rather than in the switch.
BoardWires3D — every wire as one flat batch plus the dangling preview; the lab’s lineOf styles them.
PartPlacer — the palette’s parts as one handheld: take, ghost, place.
BoardPalette — presets, parts and tools in foldable sections.
PartCard — the selection card with the domain’s rows between the kernel’s title/reading and plot/tag rows; a keyboard target via keys.
BoardOverlay — value labels, wire readings, watch marks, pinned tags.

Chrome — what makes two labs look like one product

Everything below was hand-rolled in two labs before it moved here.

LabPanel — the titled paper panel every HUD is made of; children stack, or set a size and anchor to its body.
LabKeys / LabHelp — the canonical key map (1..9 presets, T flow, f jump labels / ⇧F frame (plain F in a jump-less lab), 0 reset, H takes the next instrument, P keeps its reading, Shift+R record, ? help, arrows and WASD travel, Shift+arrows turn) plus the lab’s own keys as data. The arrows used to turn, which a drag already did well; crossing the scene had no key at all, so turning moved onto Shift and watching moved off W to Q. f/⇧F are the map’s first Shift-differentiated pair - f acquires a target, ⇧F frames it. While a flow runs →/← and Space are the flow’s, so the arrows are the camera’s only when nothing narrates.
HintJump — keyboard selection: f labels every target the lab names (1–2 home-row letters), typing one selects it in place; off-screen targets become a grouped badge strip and do fly on pick. The lab supplies targets() (id, world pos, name, group) and wires jump: on LabKeys; the letters are physical, the capture follows the pin-prompt guard, and a focus loss puts the labels away. Declaring a key is what documents it: LabHelp renders the map from the same list, so the two can never drift. The six travel letters are reserved and dispatched after the lab’s own keys, so claiming one silently costs a pan direction.
HintBar — bottom-centre line that steps aside while a flow narrates and stays width-capped against its neighbours.
ScenarioBar — clickable preset chips, each with the one-line reason it exists (scenario.note.<name>).
WatchMonitor — watch a thing, get a probe, a colour and a curve; owns probe lifecycle, stable names and the one-quantity-per-axis rule — which, since traces became (id, quantity) pairs (traceIn), means one strip per traced quantity, stacked on a shared time axis and cursor (maxStrips, default 3). A part keeps one colour across strips, so its WatchMark matches every curve it owns. WatchChip is the per-object toggle that feeds it (watch / watched / plot full, the limit read off the monitor), WatchMark the dot the object then wears in the world, in its curve’s colour.
WorldLabel — 2D paper chip pinned to a 3D point.
MarkLayer — rings on the world points something is naming right now, optionally captioned. Fed by a FlowStep.mark list or a performance script’s *mark ...* cue; keepOut keeps a ring off a presenter standing in front of the part it marks.
SelectionFrame3D — the shared hover/select language on the work surface (thin outline hovering, full frame plus facing mark selected). Used by the circuit kit; note that its lift is measured from the object, so a part sunk into its board needs a matching height.
Compass — which way the work surface faces while you circle it.
GridMode — snap/free placement with grafli’s contract (# cycles, Alt inverts for one gesture). It holds the mode and draws nothing; LabStage3D is what shows it.
LabStage3D — the ground every 3D lab stands on, plus the light rig and the SceneEnvironment that go with it. One quad, no texture: the raster is computed in the fragment shader from world coordinates, so it is millimeter paper on the light palette and blueprint on the dark one, one line weight at any zoom, and it dissolves into the sky rather than ending at a board edge. It shows GridMode’s mode as crosses or dots at the intersections, answers worldAt(view, mx, my) for mouse editing, and publishes the height/depthBias budget flat overlays have to stay inside. Three labs built a table, a sheet, a rim, a light rig and 585 peg Models between them before this existed. Three things to know: GridMode draws nothing - hand it over with gridMode: and set cueSize: 0 in a lab that places nothing, because a snap cue on a surface nobody snaps to is a lie; worldAt(view, mx, my) is the pick, the plane being the only pickable thing the stage adds (a raster not centred on the origin says so with rasterOrigin); and flat markings sit between overlayMinY and overlayMaxY (overlayY(layer) stacks them) with a depthBias in overlayMinBias..overlayMaxBias - depthBias only settles sort order, so the lift is what actually does the work.

Instruments — the shelf

Promoted from the labs, which had proved each of them (some three times over):

InstrumentScale — what a reading means, with nothing that draws it: value or probe, unit, fixed limits or a self-ranging set of ranges, linear or log positioning, severity bands, nice-number gradations, and the lag and peak-hold of a real movement. One of these feeds as many faces as the page shows, so they cannot disagree; adaptability lives in the model x face matrix, so a music VU meter is a BarFace on a log scale with peak-hold, not a new component. Bands (okUntil/warnUntil, or zones) are the scale’s, not the face’s: declared once they colour the needle, the fill, the digits and the tint behind them from LabTheme’s severity tokens, and a reading past the end of the scale takes the band at that end
- a pinned needle on a red-topped dial must not read back “ok”. settleTime is a swing for a value that changes on an action; damping is the lag of a real movement, for a continuously noisy one. Never both. Which face: Gauge for what is this relative to what the instrument can take, BarFace for how far along, ColumnFace for how much read off the scale, DigitFace for what is the number - paired with a needle or a column, because alone it says nothing about what the number is worth. demo/Instruments.qml is the reference page: one scale under four faces.
Gauge — the needle face. Given ranges it selects its own, and prints the one it settled on. Laid out in fractions of its own size, so the same component serves a HUD dial and a Texture baked onto a 3D part.
BarFace — the level face, horizontal or vertical, optionally as the LED ladder of a level meter, with the held peak marked. A music VU meter is this on a log scale, not a component of its own.
ColumnFace — the thermometer face: every major gradation labelled, for a quantity read off the scale rather than as a proportion.
DigitFace — the numeric face, in mono digits through LabLang.qty().
InstrumentDock / DockedInstrument — the HUD column, where each instrument can be put away by the reader and taken back out of a tray at its foot. The visible set rides in the lab’s viewState().
ReadoutPanel / ReadoutRow — swatch · name · live value rows, built from data, with an optional share bar per row.
MiniMap — the abstract view: fit-to-content projection plus the repaint plumbing, driven by a draw(ctx, map) callback the lab supplies.
LabBanner — the centred status pill, severity in the fill and the ink from inkOn(), blinking only for a live fault.
TransportChip — sim time, pause and speed, driving SimClock.timeScale from outside.
RecIndicator — the recording dot, so a growing CSV is never a secret.

Instruments you hold

The shelf above is mounted: the lab author bound what each one measures when the lab was written, and it reads for the whole run. These are the other half — the viewer binds the subject at runtime by pointing, and the reading dies with the gesture.

HandheldInstrument — the contract. An instrument declares what a click contributes (pickKind: a "point" on the ground, an "object" in the scene, or a "moment" in sim time), how many it takes (maxPicks, 0 for an endless chain), and what the reading means (value / valueText). It handles no input and knows nothing about the camera. That is the acceptance test: a new instrument is one file saying what it picks and what that means, with no gesture code in it.
InstrumentBelt — what the viewer can pick up, and the owner of the hand’s click. One line inside the View3D (pointer: nav, unit: the lab’s unit) and the lab has a TapeMeasure and a Stopwatch; a kit’s own instrument is declared inside the belt and joins the same row. A ruler you have to install first is a ruler nobody reaches for.
TapeMeasure — the screen-space tape. Its arithmetic is measure.js, checked by node, so lengths and angles are not geometry that only exists inside a paint call.
Stopwatch — the same contract against the sim clock rather than the ground.
CameraAnchorMark — the dotted ring showing what the view is orbiting and zooming about. A screen-space overlay, because as world content it clipped into geometry at close range.

pin() is the one transition out: it names the reading, registers it as a Probe, and from then on it is sampled on the clock grid like any other — so it lands in the run record and a paper can cite it. It asks for the name because that name is what gets cited. A measurement itself is never in viewState(): it is a question being asked now, not scene state.

The mouse

One rule, and the rest follows from it: the left button is never the camera’s. A mode used to exist only because the camera wanted LMB — panning sat there, so a lab that needed LMB had to be able to take it back, and the thing that took it back was the mode. OrbitInput3D declines the left button instead, so nothing has to.

RMB drag turns the view about the point under the cursor; a right click cancels — the “put it down” gesture.
Middle drag pans, wheel zooms towards the cursor, double-click focuses. Always live, never taken away.
LMB is the lab’s: its own tool, or a click handed to whatever instrument is in the hand. Holding Space lends it to the camera for as long as the key is down.
A lab with nothing to build may spend LMB on the view deliberately (panButtons: Qt.LeftButton | Qt.MiddleButton) — one decision, made once, not a mode.

The determinism contract

Every lab must (a) derive all randomness from SimClock (seeded), (b) run correctly under the inspector’s time pause/step actions, (c) expose labInfo() — typically just return Lab.labInfo(). Same seed + same stepped frames ⇒ identical probe series.

Minimal lab skeleton

Do not write one — generate it:

tools/lab-new/lab-new <slug> --kind build|continuous|draw --purpose learning|teaching|research

The generated Sandbox.qml answers the whole conventions contract (scenarios(), applyScenario(), labInfo(), viewState(), flowActions(), …), comes with a bilingual strings.js, the records and figures drivers and the paper/board skeletons, and its template is itself a lab that ctest -R lab_new boots. tools/lab-new/README.md explains the tokens and how a kind is added.

See demo/Sandbox.qml — a damped oscillator with a noisy measurement, used as an excuse to put every instrument on one page, and the fastest way to see whether a change to the palette or the scale has broken anything. Render it at two scales in two themes:

clayrender plugins/clay_lab/demo/Sandbox.qml --out shot.png --size 1400x900 \
    --eval 'LabTheme.mode = "dark"' --eval 'LabTheme.uiScale = 1.6' --frames 300

labs/electronics-101/ and labs/hydraulics-101/ are full build labs on the board layer.

API Reference

BarFace A level bar on an InstrumentScale - horizontal or vertical, with peak-hold

Name	Type	Description
`frameRadius`	`real`	Corner radius of the frame - 0 when baked into a Texture
`horizontal` readonly	`bool`	True while the bar runs left to right
`label`	`string`	Caption above the bar; empty hides the row
`orientation`	`int`	Qt.Horizontal (default) or Qt.Vertical
`scale`	`InstrumentScale`	Measurement model this face draws
`segments`	`int`	Split the fill into this many cells - 0 (default) is a continuous bar
`showFrame`	`bool`	Draw the panel background and border behind the face
`showPeak`	`bool`	Mark the held peak. Follows scale.peakHold by default
`showTicks`	`bool`	Draw the scale's gradations along the bar
`showValue`	`bool`	Print the reading beside the label
`showZones`	`bool`	Tint the severity bands into the track
`thickness`	`real`	Across-the-bar size of the track

Name	Type	Description
`cell`	`real`
`cell \brief World units per cell.`	`real`
`cols`	`int`
`cols \brief Cells across.`	`int`
`cursorHeight`	`real`
`cursorHeight \brief The y \l cursorW is reported at.`	`real`
`cursorW`	`var`
`cursorW \brief The cursor on the board, in world units.`	`var`
`eraser`	`bool`
`eraser \brief The eraser tool is on.`	`bool`
`hoverHit`	`var`
`hoverHit \brief What is under the cursor, as \l hitAt reports it.`	`var`
`lane`	`real`
`lane \brief The raster a router turns on; half a cell by default.`	`real`
`nextId`	`int`
`nextId \brief The next id handed out, shared by parts and wires.`	`int`
`padY`	`real`	A pad in world space, turned with its part; y is padY
`parts`	`var`	[{ id, type, col, row, rot, ...fields }] - col/row are fractional cells
`rev`	`int`	Bumped by every mutation and every move; the dependency in-place edits need
`router`	`var`	Optional: { all(links, obstacles, lane), one(a, b, lane) } choosing wire paths
`routes` readonly	`var`	Every wire's drawn path, { wireId: [{x, z}, ...] }, from the router
`rows`	`int`
`rows \brief Cells deep.`	`int`
`selectedId`	`int`
`selectedId \brief The selected part, -1 for none.`	`int`
`spec`	`var`	Domain's part types: { type: { terminals, half, actuator, keepOut, fields, rows, watch } }
`wires`	`var`
`wires \brief \c {[{ id, a: [partId, ti], b: [partId, ti] }]}.`	`var`
`wiringFrom`	`var`
`wiringFrom \brief \c while a wire is dangling.`	`var`

Method	Returns	Description
`actuatorHalf(string type)`	`var`
`addJunction(real col, real row)`	`int`
`addPart(string type, real col, real row)`	`int`
`addRotated(string type, real col, real row, int quarters)`	`int`
`addWire(var a, var b)`	`void`
`beginBatch()`	`void`
`bodyHalf(string type)`	`var`
`bounds(var which, real pad)`	`var`
`cellFree(real col, real row, int ignoreId, string type)`	`bool`
`cellX(real col)`	`real`
`cellZ(real row)`	`real`
`clear()`	`void`
`closestOnPath(var path, real x, real z)`	`var`
`colOf(real x)`	`real`
`endBatch()`	`void`
`hitAt(real wx, real wz)`	`var`
`jumpTargets(var labelOf, var groupOf, real y)`	`var`
`keepOut(string type)`	`int`
`keys(var grid, var overlay)`	`var`
`load(var s)`	`void`
`movePart(int id, real col, real row, bool snap)`	`void`
`nearestFreeCell(real col, real row, string type)`	`var`
`partAt(int id)`	`var`
`previewPath(var from, var to)`	`var`
`removePart(int id)`	`void`
`removeWire(int id)`	`void`
`rotatePart(int id)`	`void`
`rowOf(real z)`	`real`
`selectionKeys(var monitor, var grid)`	`var`
`setField(int id, string key, var value)`	`bool`
`specOf(string type)`	`var`
`splitWireAt(int wireId, real wx, real wz)`	`int`
`state()`	`var`
`terminalCount(string type)`	`int`
`terminalDir(int id, int ti)`	`var`
`terminalLocal(string type, int ti)`	`var`
`wireMid(var wire)`	`var`
`wirePath(var wire)`	`var`

Signal	Description
`changed(string kind)`
`cleared()`
`removed(int id)`

Search Results

Lab Plugin

Components

Focus mode

The board — what a build lab is made of

Chrome — what makes two labs look like one product

Instruments — the shelf

Instruments you hold

The mouse

The determinism contract

Minimal lab skeleton

API Reference

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