meshoptimizer

meshoptimizer, the mesh optimization library, through C++23 modules.

English · 简体中文 · Upstream · Releases · mcpp · Index

The upstream API is unchanged: every meshopt_* function, struct, enum and enumerator of <meshoptimizer.h> is the upstream global, the header's C++ overloads over index types included (unsigned short indices work as they do with the header). The whole library — indexing, vertex cache / overdraw / vertex fetch optimization, simplification, meshlets, spatial ordering, the vertex, index and meshlet codecs — is vendored byte for byte from the 1.3 release and built with the package; nothing else is linked.

The library is built with -ffp-contract=off and without fast math, so the same input gives the same output bit for bit on every platform: with the platform's own default arm64 fuses a multiply and an add into one rounding and the meshlets of a scattered 48 × 48 sheet differ from x86-64's (from 1.3.1; 1.3 kept the platform's default).

Modules

• import mcpplibs.mwrap.meshoptimizer;: the whole API (118 names: 9 types, 20 enumerators, 89 functions), re-exporting the one below
• import mcpplibs.mwrap.meshoptimizer.macros;: MESHOPTIMIZER_VERSION in mcpplibs::mwrap::meshoptimizer::macros

More Modules API -> upstream's README, which documents every function

Getting started

mcpp new lod --template mcpplibs.mwrap.meshoptimizer@1.3.1
cd lod
mcpp run

The default template indexes a grid of quads, orders it for the vertex cache and simplifies it to a tenth of its triangles.

[dependencies]
mcpplibs.mwrap.meshoptimizer = "1.3.1"

import std;
import mcpplibs.mwrap.meshoptimizer;

int main() {
    std::vector<float>        positions = /* x y z … */ {0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0};
    std::vector<unsigned int> indices{0, 1, 2, 0, 2, 3};
    meshopt_optimizeVertexCache(indices.data(), indices.data(), indices.size(), positions.size() / 3);
    std::vector<unsigned int> fewer(indices.size());
    const std::size_t kept = meshopt_simplify(fewer.data(), indices.data(), indices.size(), positions.data(), positions.size() / 3, 3 * sizeof(float), 3, 0.05f);
    std::println("{} of {} indices kept", kept, indices.size());
}

Macros

A named module cannot export a macro. MESHOPTIMIZER_VERSION (1030 for 1.3) is inline constexpr int under its original name:

namespace macros = mcpplibs::mwrap::meshoptimizer::macros;
static_assert(macros::MESHOPTIMIZER_VERSION >= 1030);

The header's other macros (MESHOPTIMIZER_API, MESHOPTIMIZER_EXPERIMENTAL, MESHOPTIMIZER_ALLOC_CALLCONV) decorate its own declarations; a consumer does not spell them. A translation unit that also includes <meshoptimizer.h> (add upstream/meshoptimizer/src to its include path) sees the same entities; while the header's macro is defined it expands inside the qualified name too (tests/header_mix_test.cpp shows the order and push_macro).

What is and is not wrapped

• Wrapped: the library (src/), every public name. meshopt_IndexAdapter, the header's helper for its own templates, is not exported.
• The functions upstream marks experimental (MESHOPTIMIZER_EXPERIMENTAL) are exported as they are; their signatures may change with upstream.
• Not here: gltfpack, the JavaScript and Rust bindings, the demo.
• The custom allocator (meshopt_setAllocator) is process-wide, as upstream's.

Verification

• mcpp test: indexing, vertex cache order, simplification, meshlets and their bounds, both codecs' round trips, the short-index overloads, header mixing, the macro mapping.
• python3 tools/check_exports.py: src/meshoptimizer.cppm is exactly what tools/surface.py derives from the header; no meshopt_* name of the header is left out.
• python3 tools/test_template.py: mcpp new from an installed copy, a strict build, and a run of the generated project.
• CI: Linux (GCC 16, LLVM 23), macOS and Windows (LLVM 23).

License

The wrapper is Apache-2.0 (mcpp-community). meshoptimizer is MIT, © Arseny Kapoulkine; its README and license are kept in upstream/meshoptimizer/ and deployed with a program's licenses. Provenance: upstream/documents.json.