# Busker droid

A one-machine band whose pose comes from data: a step pattern raises each beater as its step comes round and drops it on the beat, and both arms are solved to what they are about to hit.

> For the complete index, see [llms.txt](https://robocn.dev/llms.txt). A Markdown version of any page is available by appending `.md` to its URL or by sending an `Accept: text/markdown` header.

## Install

```bash
bunx --bun shadcn@latest add https://robocn.dev/r/busker-droid.json
```

Registry item: `busker-droid` · [`https://robocn.dev/r/busker-droid.json`](https://robocn.dev/r/busker-droid.json)

## Notes

- The only machine in the set whose pose comes from data you pass it. Every other droid here is posed or follows a pointer; this one reads a pattern, which is the same pattern `music-box-drum` carries as pins on its barrel.
- The up-stroke is slow and the down-stroke is one frame, because that is what `combLift` does: it rises over two thirds of a step and drops to nothing at the step itself. The strike is the drop.
- Both arms are two-link solutions, each solved in the vertical plane that contains its own shoulder and its own target — the plane the arm actually swings in. A target out of reach straightens the arm rather than stretching it.
- The kit is illustrated, not solved: the drums are cylinders and the cymbal a tipped disc, with no membrane, no stand compliance and no sound. The head's nod and the body's bob are driven off the kick's release rather than being a separate animation.
- An original archetype. No performer, band, maker or livery is reproduced here or in the demo.

## Usage

```tsx
import { BuskerDroid } from "@/components/ui/busker-droid"

<BuskerDroid behavior="groove" />

// Your own figure — kick, snare, cymbal — or a bar you can scrub.
<BuskerDroid pattern={["x...x...", "....x...", "..x...x."]} />
<BuskerDroid interactive onStepChange={setStep} />
```

## Props

| name | type | default | description |
| --- | --- | --- | --- |
| `view` | `"plan" | "front" | "profile" | "iso"` | `"front"` | Where the camera stands. One droid, four projections: straight down, straight on, side elevation, or three-quarter from above. |
| `beat` | `number` | — | Controlled position through the pattern, in steps. Omit it and it runs behavior. |
| `behavior` | `"groove" | "fill" | "static"` | `"groove"` | Play the pattern once a cycle, or run it at double time. |
| `pattern` | `readonly string[]` | `a plain sixteen-step figure` | One row per voice — kick, snare, cymbal — where any non-blank character is a hit. An empty array is a machine that keeps time and strikes nothing. |
| `speed` | `number` | `0.55` | Passes of the whole pattern per second. |
| `animate` | `boolean` | `true` | Off parks the machine at phase and stops rendering. A reduced-motion preference does the same. |
| `paused` | `boolean` | `false` | Freeze where it stands. |
| `phase` | `number` | `0` | Seconds of offset, so a row of machines breaks step. |
| `interactive` | `boolean` | `false` | Drag across to scrub the pattern — the frame's width is one pass — or arrow-key it a step at a time. |
| `onBeatChange` | `(beat: number) => void` | — | Position through the pattern throughout a drag or a key press. |
| `onStepChange` | `(step: number) => void` | — | The step now under the beaters, 0-based. |
| `showGround` | `boolean` | `true` | Draw the contact shadow beneath the machine. |
| `label` | `string` | — | Caption below the state readout. |
| `variant` | `"solid" | "outline" | "blueprint" | "wire"` | `"solid"` | How the machine is painted. Geometry never changes between variants. |
| `size` | `"xs" | "sm" | "md" | "lg" | "xl" | number` | `"md"` | Rendered width in pixels, or a step on the scale. |
| `color` | `string` | `var(--robot-shell)` | Body panels — the colour the machine reads as. |
| `accent` | `string` | `var(--robot-accent)` | Status colour: tip light, live tool, readouts. |
| `metal` | `string` | `var(--robot-metal)` | Bare machined parts: collars, bolts, tool bodies. |
| `dark` | `string` | `var(--robot-dark)` | Cast joints, base, shadow side. |
| `palette` | `Partial<RobotPalette>` | — | Override any subset of roles at once, including glow and grid. |

## Source

- `src/components/ui/busker-droid.tsx`