Flipbook

@drawcall/flipbook

Use @drawcall/flipbook for lightweight Three.js billboard effects loaded from KTX2 sprite sheets. Get ready-to-use flipbook assets from @drawcall/market.

A pre-rendered sprite sheet is the right choice for art-directed effects — explosions, flames, magic, impacts — where it looks far better than code-built particles and costs almost nothing at runtime. For procedural, parametric bursts instead (sparks thrown along a surface normal, physics debris, a count/direction that varies per event), use the pooled particles. The two compose: a flipbook explosion plus a procedural debris burst reads better than either alone.

Install

pnpm add @drawcall/flipbook three

three is a peer dependency.

Basic Use

import { Flipbook } from "@drawcall/flipbook";
import { KTX2Loader } from "three/addons/loaders/KTX2Loader.js";

const ktx2Loader = new KTX2Loader()
  .setTranscoderPath("/basis/")
  .detectSupport(renderer);
Flipbook.setKtx2Loader(ktx2Loader);

const flame = new Flipbook("/flame.ktx2", {
  height: 0.6,
  origin: "bottom-center",
  billboard: "cylindrical"
});

scene.add(flame);
await flame.ready;

function animate(deltaSeconds: number) {
  flame.update(deltaSeconds);
}

Use new Flipbook(url, options) when the asset URL is known up front. Use new Flipbook(options).load(url) or .setData(bytes) when loading is controlled elsewhere.

KTX2Loader needs the Basis transcoder files (basis_transcoder.js + .wasm) served at the path you pass to setTranscoderPath. They are not bundled — copy them from three/examples/jsm/libs/basis/ into your served static dir (e.g. public/basis/). Without them, Basis-compressed .ktx2 files fail to decode and nothing renders — the most common "flipbook shows nothing" cause.

Get Assets

Prefer @drawcall/market for flipbook assets:

npx @drawcall/market search --type flipbook "flame"

Use the downloaded .ktx2 file as the Flipbook URL, for example new Flipbook("/effects/flame.ktx2").

KTX2 Requirements

The KTX2 may be Basis-compressed KTX2 loaded through Three.js KTX2Loader, or uncompressed R8G8B8A8.

Required metadata:

• flipbook.columns
• flipbook.rows

Optional metadata:

• flipbook.aspectRatio, defaults to the per-frame texture aspect ratio
• flipbook.frames, defaults to columns * rows
• flipbook.duration, defaults to frames / 24
• flipbook.playbackRate, defaults to 1
• flipbook.billboard, supports spherical, cylindrical, and none

Options

• height: world-space plane height; width comes from aspectRatio
• origin: use "bottom-center" for flames, torches, impacts, and ground-anchored effects
• billboard: use "spherical" for free-facing sprites, "cylindrical" for upright Y-axis sprites, and "none" for manually oriented meshes
• playbackRate: multiply the asset playback speed
• loop: set false for one-shot effects like explosions
• autoPlay: set false when triggering manually
• opacity: material opacity multiplier
• randomStart: keep true for many looping effects so instances do not sync

Common Patterns

One-shot impact:

const impact = new Flipbook("/impact.ktx2", {
  autoPlay: false,
  loop: false,
  origin: "bottom-center"
});

impact.restart();

Many looping particles:

const sparks = positions.map((position) => {
  const spark = new Flipbook("/spark.ktx2", {
    height: 0.25,
    randomStart: true
  });

  spark.position.copy(position);
  scene.add(spark);
  return spark;
});

function animate(deltaSeconds: number) {
  for (const spark of sparks) spark.update(deltaSeconds);
}

Debugging

• If nothing appears, await flipbook.ready and check the URL response.
• If frames are wrong, inspect flipbook.columns, flipbook.rows, and flipbook.frames metadata.
• If the sprite faces oddly, switch between spherical, cylindrical, and none.
• If the effect floats or sinks, adjust origin before adjusting mesh position.
• If one-shot effects loop, set loop: false.