# WindHandle

> Talos next · Since 0.7; changed in next

The scene's wind (`meta.environment.air.wind`) at `ctx.time.now`: the air the dry probes of `buoyancy` bodies are dragged against.

A replay reads the same numbers.

## Signature

```ts
export interface WindHandle {
  /**
   * The air's velocity at world (x, y, z), `[x, y, z]` m/s: zero in still air or in a scene with no
   * `meta.environment.air`. Throws a `RangeError` (`fluid.sample-invalid`) for a coordinate that is
   * not a finite number.
   */
  sample(x: number, y: number, z: number): Vec3
  /**
   * Changes the running wind at once; what this does not name stays. False in a scene with no
   * `meta.environment.air`. Throws a `RangeError` (`wind.set-invalid`) for a bad argument.
   */
  set(wind: { speedMps?: number; directionRad?: number; gustMps?: number; gustPeriodS?: number }): boolean
}
```

Import: `import type { WindHandle } from "@argus/api"`

## Members

| Member | Signature | Description |
|---|---|---|
| `sample` | `sample(x: number, y: number, z: number): Vec3` | The air's velocity at world (x, y, z), `[x, y, z]` m/s: zero in still air or in a scene with no `meta.environment.air`. Throws a `RangeError` (`fluid.sample-invalid`) for a coordinate that is not a finite number. |
| `set` | `set(wind: { speedMps?: number; directionRad?: number; gustMps?: number; gustPeriodS?: number }): boolean` | Changes the running wind at once; what this does not name stays. False in a scene with no `meta.environment.air`. Throws a `RangeError` (`wind.set-invalid`) for a bad argument. |

## Example

The tested fixture `fixtures/recipes/jump-pad-and-elevator/scenes/behaviors/camera-zone.ts`.

```ts
import type { Behavior } from "@argus/api"

/**
 * A trigger volume that retunes the camera while the player is inside it.
 *
 * The engine has no camera-zone concept and needs none: a volume, a `trigger` component and this.
 * Here the player's behaviour owns the camera (it re-sends its params when the view is turned), so
 * the zone tells it what to change rather than calling `ctx.camera.set` itself. In a scene where
 * nothing else writes the camera, the zone can call `ctx.camera.set(kind, params)` directly.
 */
interface Props {
  /** `ctx.camera.set` params to merge in on the way in, and on the way out. */
  inside?: Record<string, unknown>
  outside?: Record<string, unknown>
}

export default {
  onTrigger(ctx, trigger) {
    const params = trigger.entering ? ctx.props.inside : ctx.props.outside
    if (params) ctx.events.emit("camera-zone", { target: trigger.other.id, params })
  },
} satisfies Behavior<Record<string, never>, Props>
```