Fireflies

A meadow at dusk.

isomer.sh/effects/fireflies

Knobs

Continue on iPhone
Preset
#D2EE6A
#1C3366
40.0
1.00
Light1
1.00
Shape2
1.00
0.60
Motion3
1.00
1.00
1.00
Texture1
0.35
Follow the pointer

Drives tiltX and tiltY.

Still frame

What reduced motion shows: 6 s.

Install

Code

components/isomer/fireflies.tsx
'use client';
// Generated by isomer. Do not edit by hand; run `isomer add` again to update. (from packages/react/src/Fireflies.tsx)
// generated by packages/react/scripts/gen-components.mjs, do not edit
import type { CSSProperties } from 'react';
import { useIsomerCanvas, usePrefersReducedMotion, type Mount } from './useIsomerCanvas';
import { useLive, usePointer, type LiveSpec } from './live';
// @ts-ignore: the runtime is plain JS with no type declarations
import * as runtime from './fireflies.js';

const { DEFAULTS, mount } = runtime as { DEFAULTS: FirefliesKnobs; mount: Mount };

export interface FirefliesKnobs {
  tiltX: number;
  tiltY: number;
  firefly: string;
  sky: string;
  count: number;
  glow: number;
  brightness: number;
  grassHeight: number;
  depth: number;
  drift: number;
  blinkRate: number;
  sway: number;
  grain: number;
}

export interface FirefliesProps extends Partial<FirefliesKnobs> {
  className?: string;
  style?: CSSProperties;
  /** Render this one frame (seconds) and run no clock. Used by the parity tests. */
  time?: number;
  paused?: boolean;
  /** Draw t = 6 once when the user prefers reduced motion. Default true. */
  respectReducedMotion?: boolean;
  /** Keep each frame readable after it is shown, for canvas.toDataURL or readPixels. Read at mount. Default false. */
  preserveDrawingBuffer?: boolean;
  /**
   * Live inputs, when there is no `time` and the user does not prefer reduced motion: tiltX, tiltY add the
   * device tilt (the pointer until it arrives; iOS Safari needs `requestTilt()` from a tap), each through one
   * follow spring, with the props as the rest. Default true.
   */
  live?: boolean;
}

/** Where each live input comes from: the spec's `live` block. */
const LIVE: LiveSpec<FirefliesKnobs> = {
  inputs: [{ name: 'tiltX', source: 'tilt.x' }, { name: 'tiltY', source: 'tilt.y' }],
  follow: { stiffness: 1200.0, dampingRatio: 1.0 },
};

export const firefliesDefaults: Readonly<FirefliesKnobs> = DEFAULTS;

export function Fireflies({ className, style, time, paused, respectReducedMotion, preserveDrawingBuffer, live, ...props }: FirefliesProps) {
  const knobs = { ...DEFAULTS };
  for (const k of Object.keys(DEFAULTS) as (keyof FirefliesKnobs)[]) {
    const v = props[k];
    if (v !== undefined) (knobs as Record<string, unknown>)[k] = v;
  }
  // A fixed time is test mode, and reduced motion draws the poster: either way the live inputs stay off (no
  // sensors, no pointer, no events) and the knobs render as given.
  const reduced = usePrefersReducedMotion() && respectReducedMotion !== false;
  const inputs = useLive(LIVE, mount, knobs, time === undefined && live !== false && !reduced);
  const ref = useIsomerCanvas({ mount: inputs.mount, knobs, time, paused, respectReducedMotion, preserveDrawingBuffer, posterTime: 6.0 });
  usePointer(ref, inputs);
  return <canvas ref={ref} className={className} style={{ display: 'block', width: '100%', height: '100%', ...style }} />;
}

Parity

iPhone 17 Pro simulator, iOS 26.3.1 against Chromium headless + SwiftShader, 15 October 2026.