# keyframe-resample-wasm
[](https://www.npmjs.com/package/keyframe-resample)
[](https://github.com/donmccurdy/keyframe-resample-wasm/actions?query=workflow%3ACI)
Resamples and optimizes keyframe data using WebAssembly. Minzipped size is about 6-7 kb.
## Installation
```
npm install --save keyframe-resample
```
### Compatibility
The `keyframe-resample` module will load a WebAssembly binary as a static resource, as described in [Web.Dev: Bundling non-JavaScript resources
](https://web.dev/bundling-non-js-resources/#universal-pattern-for-browsers-and-bundlers). This method in compatible with Node.js, most browsers, and applications compiled with a modern bundler. For older bundlers, a `keyframe-resample/compat` module is also available, loading the WebAssembly binary from an inline Data URI. The compatibility build is a couple kilobytes larger, and requires more time to process the WebAssembly binary.
## API
```javascript
import { ready, resample } from 'keyframe-resample'; // Node.js, browsers, and modern bundlers
import { ready, resample } from 'keyframe-resample/compat'; // Legacy bundlers
// wait for WASM to compile
await ready;
// keyframe times, in seconds
const srcTimes = new Float32Array([0, 0.1, 0.2, 0.3, 0.4]);
// keyframe values, N-dimensional vectors
const srcValues = new Float32Array([
0, 0, 1,
0, 0, 2,
0, 0, 3,
0, 0, 4,
0, 0, 5,
]);
// resample keyframes, remove those unnecessary with interpolation.
const count = resample(srcTimes, srcValues, 'lerp');
// results are written to start of source array.
const dstTimes = srcTimes.slice(0, count); // → [0, 0.4]
const dstValues = srcValues.slice(0, count * 3); // → [0, 0, 1, 0, 0, 5]
```
In addition to the `resample(...)` function implemented in WebAssembly, a `resampleDebug(...)` function implemented in plain JavaScript is also exported. The WebAssembly implementation runs considerably faster.
### Exports
| export | description |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------|
| | |
| ready: Promise<void>
| Promise resolving when WASM is initialized and module is ready for use. |
| | |
| resample(
times: Float32Array,
values: Float32Array,
interp: 'step' \| 'lerp' \| 'slerp',
tolerance = 1e4
)
| WebAssembly implementation of keyframe interpolation. |
| | |
| resampleDebug(
times: Float32Array,
values: Float32Array,
interp: 'step' \| 'lerp' \| 'slerp',
tolerance = 1e4
)
| JavaScript implementation of keyframe interpolation. |
### Interpolation modes
| mode | description |
|-----------|-------------------------------------------------------------|
| `'step'` | Step (also called discrete or constant) interpolation. |
| `'lerp'` | Linear, per-component interpolation. |
| `'slerp'` | Spherical linear interpolation, valid only for quaternions. |
## Contributing
To build the project locally, run:
```
npm install
npm run dist
```
To test changes:
```
npm run test
npm run benchmark
```
Optimizations and bug fixes are welcome. Please consider filing an issue to discuss possible
feature additions.
## License
Licensed under [Blue Oak Model License 1.0.0](./LICENSE.md).