Systems

C mesh library

OBJ/PLY reading and writing, CLI, compiled to WebAssembly for an in-browser demo.

Done Sprint S2-S6+S42 · 10 points

In short, no jargon for non-developersRead the summaryClose

What it is: A building block that reads the most common 3D files, those of modelling software and 3D printers, and computes their characteristics.
What it is for: Several other projects of the portfolio rely on it: it has to be fast and never crash, even on a damaged file.
What it shows: Rigour on code close to the machine, in the C language: millions of damaged files tried, no memory leak, the same result on Windows, macOS and Linux.

Taught in L3 (advanced C programming)

How the pieces fit together

Files (OBJ, PLY, STL) → Readers (C11, no dependency): read line by line
libFuzzer (ASan, UBSan) → Readers (C11, no dependency): random inputs
Readers (C11, no dependency) → Mesh (vertices, triangles, edges): build
Mesh (vertices, triangles, edges) → meshinfo (command line)
Readers (C11, no dependency) → WebAssembly (the page's demo): built by Emscripten

The file is read by the C library compiled to WebAssembly: it never leaves your browser.

Choose an OBJ, PLY or STL file or drop it here

Samples:

C: The OBJ, PLY and STL readers and the basic topology (edges, boundaries, χ), in C11, with typed errors and their line number.
CMake: Building and testing with GCC, Clang and MSVC; the same reader is reused by the topology, parallel, Qt and ray tracer projects.
Emscripten: Compiles the library to WebAssembly for the project page demo: the file never leaves the browser.
Unity: The C unit tests: each format, each error and its line.
Valgrind: Checks for leaks and invalid memory accesses on the tests and the meshinfo command.
libFuzzer: Feeds millions of random inputs to the readers, with ASan and UBSan, on every push in CI.