Add SPZ gaussian splat format support via external parser#9018
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Adds a parser for the SPZ format (https://github.com/nianticlabs/spz), version 4, implemented outside the engine as a script (scripts/esm/gsplat/spz-parser.mjs) and registered with the gsplat resource handler by the application. The splat data is kept in its quantized form on the GPU (~20 bytes per splat plus spherical harmonics) and dequantized in the shader, similar to the compressed PLY and SOG formats. The ZSTD compressed attribute streams are decompressed using a wasm module registered draco-style via pc.WasmModule, with the decoder vendored into examples assets. Includes a new gaussian-splatting/simple-spz example with the biker asset converted to spz v4.
Build size reportThis PR does not change the size of the minified bundles.
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This was referenced Jul 3, 2026
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Adds support for loading gaussian splats from SPZ files (version 4), implemented as an external parser script rather than engine code, using the parser registry on the gsplat resource handler.
Changes:
scripts/esm/gsplat/spz-parser.mjs-SpzParserwhich applications register viaapp.loader.getHandler('gsplat').addParser(new SpzParser(app)). The parser reads the SPZ v4 (NGSP) container directly and keeps the splat data in its quantized form in GPU textures (~20 bytes per splat plus optional spherical harmonics), dequantizing it in the shader - similar to the compressed PLY and SOG formats. Supports 0-3 SH bands (degree 4 files are clamped to 3 bands), and both GLSL and WGSL.zstddeclibcompiled to wasm, 54kB) is vendored intoexamples/assets/wasm/zstd/with provenance and licenses documented in the wasm assets README.GSplatResourceBase/GSplatFormatAPI.Examples:
gaussian-splatting/viewerexample now accepts dropped.spzfiles (loaded with +Y up, no flip rotation).gaussian-splatting/simple-spzexample, loading the biker asset converted to spz v4 (2.1MB vs 2.5MB compressed ply). Verified on WebGL2 and WebGPU, with spherical harmonics additionally verified using an SH3 test asset.