Fast sdf generator from bezier curves or svg string.
npm install webgl2-sdfBug reports, pull requests and ⭐⭐⭐⭐⭐s are welcome and appreciated!
An ultra-fast library to generate the signed distance field (sdf) of an array
of bezier curves (lines, quadratics, cubics), typically some closed shape(s).
dozens of times faster* than webgl-sdf-generator for real-time (60+ fps)
applications even on slow on-board GPUs
The bezier curves can be given in raw form or as an SVG path string (except, arcs are
not supported yet).
Supported path commands: L, Q, C, H, V, S, T, Z l, q, c, h, v, s, t, z
``cli`
npm install webgl2-sdf
typescript
import { getWebGlContext, generateSdf, GLSL_PATTERN1 } from "webgl2-sdf";
function drawSdf() {
const gl: WebGL2RenderingContext = canvas.getContext(
'webgl2',
{
depth: false, stencil: false, antialias: false,
premultipliedAlpha: false, preserveDrawingBuffer: true
}
);
const { width: canvasWidth, height: canvasHeight } = canvas.getBoundingClientRect();
// The first call to
getWebGlContext caches some context, e.g. compiled shader
// programs, etc., subsequent calls simply uses the existing cache.
const glContext = getWebGlContext(gl!); // Optional...
glContext.onContextLoss = onContextLoss;
const someShape =
; try {
generateSdf(
glContext!,
someShape,
[-50, -50, 150, 150], // viewBox
canvasWidth, // width (of drawing area)
canvasHeight, // height (of drawing area)
50, // max sdf distance
// The below options are optional (see function signature for details)
{
x: 0, y: 0, // canvas x, y coordinates; [0,0] is bottom left!
testInteriorExterior: true,
calcSdfForInside: true,
calcSdfForOutside: true,
customData: [
2.0, // exponent when using default
glslRgbaCalcStr
0, 0, 0
],
colorMask: [true, true, true, true],
// glslRgbaCalcStr: GLSL_PATTERN1
}
);
} catch (e) {
console.log(e);
}
}
function onContextLoss(event: Event) {
// ... do somethin when context is lost, most likely by re-establishing a new context
console.log(event);
}
// At the end, **only after you know you'll never call
// again on the same **
// freeGlContext(glContext); // dispose of textures, buffers, shaders, programs, etc.`Recommendations
When calling :* ensure the drawing
width and height has the same aspect ratio as the viewbox
else the image will be squashed / stretched
the viewbox is given as [x1,y1,x2,y2] and not* as [x,y,width,height] as in SVG
* note the premultipliedAlpha option when calling getContext and set it to your needs
* if you want to combine a standard CanvasRenderingContext2D with a WebGL2RenderingContext
it is best practice to have 2 canvases in your html that is stacked on top of each otherESM only
This package is ESM only.
It can be used in
The MIT License (MIT)
Copyright © 2026 Floris Steenkamp
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.