CPU rasteriser, compiled to WebAssembly. A glTF 2.0 binary in, an RGBA image out.
Node 22 or later. ESM only. No runtime dependencies.
npm install @pcbjs/rendererimport { readFile, writeFile } from 'node:fs/promises'
import { encodePng, render } from '@pcbjs/renderer'
const glb = await readFile('model.glb')
const { rgba, width, height } = await render(glb, {
width: 1600,
height: 1000,
camera: { type: 'fit', direction: [1, 1, 1] },
highlight: { nodes: [0], dim: 0.25 },
})
await writeFile('model.png', await encodePng(rgba, width, height))rgba is straight alpha, top row first. encodePng uses node:zlib in Node, and stored blocks where that module is missing.
createRenderer(glb) parses once. Call render again, then dispose().
For focused inspection, a fit camera accepts nodes: [0] or explicit world-space bounds: { min, max }. visibility: { only: [0], hidden: [1] } filters geometry and shadow casters per frame; hidden nodes take precedence. Selectors include descendants, and names match every occurrence. Unknown selectors throw. The API guide describes framing, visibility and structured option errors.
Use lighting: 'studio' for GGX highlights and rough studio reflections, and shadows: true for filtered directional shadows. Both are opt-in. Shadows also accept { resolution: 1024, strength: 1 }, with resolution limited to 256–2048 (at most 16 MiB of depth storage). Core glTF base-colour, metallic-roughness, normal, occlusion and emissive textures work in both lighting modes, with two UV sets, KHR_texture_transform, and authored sampler filtering including mipmaps. See the API guide for controls and limits.
Use exposure (EV stops) and toneMapping: 'reinhard' | 'aces' to control output; defaults use zero exposure adjustment and no tone mapping. KHR_materials_emissive_strength and KHR_materials_unlit are supported. Transparency adds at most 14 MiB of peeling buffers; transparency.maxLayers defaults to 32 and throws on overflow.
createRenderer(glb, { scene: 0 }) selects an authored scene. renderer.info exposes nodes, names, extras, camera/light node indices and compatibility diagnostics. Select an authored camera with { type: 'asset', node: cameraNode }, or use explicit perspective, orthographic or fit cameras. nodeTranslations provides non-destructive world-space offsets; node names and numeric indices work for highlighting. The renderer never interprets application extras.
KHR_lights_punctual supports directional, point and spot lights. Authored lights are used automatically when present, and can be replaced with lights: [...]. Base-colour factors use glTF's linear convention; load option baseColorSpace: 'srgb' accepts assets with sRGB-encoded factors. Sparse accessors and flat normals for meshes without NORMAL are supported.
Coordinates are metres, Y up, right-handed. See API and specification. This is a documented static GLB subset, not a claim of complete glTF conformance.
width and height throw above 4096 by 4096, before supersampling. supersample defaults to 2. A supersampled edge past 8192 throws before drawing.
dim 0 leaves a node. dim 1 is the background. The outline is #ffcc33, one output pixel, after downsample. BLEND composites per pixel, with a configurable layer limit; transparent materials receive but do not cast shadows. MASK discards below alphaCutoff. Lighting is linear. Base-colour textures are decoded from sRGB and the image is encoded once.