Clyune Component GalleryNoise Terrain · How it works & code
Treat smooth noise as 'elevation', sample row by row horizontally to draw lines, with distant lines on top and near lines below, and cover behind lines with solid color, forming a layered terrain...
Runtime logic
Visiting `/generative/terrain`, DemoHost lazy-loads `demos/kits/kit-generative.js` (registry `mod: 'kit-generative'`) and calls `mount(host, { variant: 'terrain' })`. mount resolves the variant to family `terrain`; `withControls` builds the control panel (6 presets + sliders). `createCanvasStage` creates the `<canvas>` (HiDPI ≤ 2×, ResizeObserver) and the info panel. The family’s `build(S)` initialises state and returns the per-frame callback. Every `requestAnimationFrame`: read controls, advance a speed-scaled clock (dt ≤ 50 ms), run the frame callback; returned readouts go to the info panel. Changing parameters: colour/speed/size apply live; structural ones remount; leaving the page cancels rAF, removes listeners and frees resources.
Environment
Canvas 2D: 2D canvas drawing; requestAnimationFrame: Display-synced animation loop; ResizeObserver: Canvas follows container size; Pointer Events: Unified mouse/touch/pen events; devicePixelRatio: Crisp HiDPI rendering (capped at 2×) · react 18.3.1, react-router-dom 6.30.6, vite 5.4.21
Dependencies
react 18.3.1
Imported APIs
withControls — Wraps the demo in the shared control panel (presets, sliders, reset); hot-updates or remounts on change; paramsFromSpec — Turns the spec (colour/speed/size/count/extras) into control-panel parameter definitions; createCanvasStage — Shared Canvas 2D stage: canvas + info panel, HiDPI, one rAF loop, pointer state, idle auto-pointer; hueOf — Hue of a colour (0–360°); clamp — Clamps a value to a range; TAU — Constant 2π; fmt — Number formatting (fixed decimals); F — Formula block HTML; S.clear — Clears with the background colour (translucent = trails); S.onFrame — Registers a per-frame callback; its return value feeds the info panel; ctx.beginPath() — Starts a new path; ctx.moveTo() — Moves the pen without drawing; ctx.lineTo() — Adds a straight line to a point; ctx.closePath() — Closes the current sub-path; ctx.fill() — Fills the current path; ctx.stroke() — Strokes the current path; ctx.arcTo() — Adds an arc using tangent lines; ctx.fillRect() — Fills a rectangle; ctx.arc() — Adds a circular arc (center, radius, start/end angle); ctx.drawImage() — Draws an image or offscreen canvas; ctx.save() — Saves the drawing state (transform, styles, clip); ctx.rect() — Adds a rectangle to the path; ctx.clip() — Turns the current path into the clipping region; ctx.restore() — Restores the saved drawing state
Source code
frontend/src/demos/kits/kit-generative.js: FAM.terrain (L271-L284)
Code walkthrough
L271-284: Calls the factory `gFam()` to produce the full definition (spec + doc + build) from the options below. L271-271: Title shown in the info and control panels: “Noise Terrain”. L271-271: Range/default of the size slider: Elevated variation. L271-271: Range/default of the count slider: S ridge count. L272-272: Extra demo-specific slider/toggle: Noise scale. L272-272: Default main colour. L272-272: Help text of the count parameter. L272-272: Preset buttons: name → parameter overrides (4). L273-273: Body of the “Notes” section. L273-273: Main formula of the “Formula” section. L273-273: Second formula line. L274-284: Per-frame draw function: draws with Canvas 2D `beginPath`, `moveTo`, `lineTo`, `closePath`, `fill`, `stroke`; math via `Math.max`, `Math.exp`, `Math.abs`; returns readouts `cell` to the info panel.
Principles
Altitude h(x, z) = fbm(x·s, z·s − 0.3t) Screen y = baseline - rise height · h · Perspective Noise terrain: smooth noise as "altitude", lined up across a line of sampling and lined up in a distance, Close to the bottom, with pure colours covering the back of the line, they form back-to-back mountain ranges (like the Joy Division cover). The terrain rolls forward, and the pointer rises a hill. Generative Art = a simple mathematical rule + Random number/噪声，让电脑自己「画」出图案；改变参数就是改变规则。