This project is a C99 application using SDL3 (no OpenGL) that implements a CPU-based software rasterizer with z-buffer, 3D transformations (rotation, translation), triangulated indexed mesh rendering, greyscale output, and normal-based Gouraud shading.

• CPU software rasterizer (no OpenGL)
• Z-buffer for depth
• 3D transformations: rotation, translation
• Triangulated indexed mesh rendering
• Greyscale output
• Gouraud shading based on vertex normals

• Requires: SDL3 development libraries (system package via pkg-config or fetch from git), C99 compiler (e.g., gcc)

By default, the build uses SDL3 from your system via pkg-config. Install SDL3 development files using your package manager:

# Example for Debian/Ubuntu:
sudo apt install libsdl3-dev

Then build with CMake:

cmake -S . -B build
cmake --build build

If you want to fetch and build SDL3 from the official git repository (e.g., for latest development version), configure CMake with:

cmake -S . -B build -DUSE_SDL3_FROM_GIT=ON
cmake --build build

This will download and build SDL3 as part of the build process.

If neither pkg-config nor git is available, the build will fail with an error.

The project also builds to WebAssembly via Emscripten. SDL3 is provided by Emscripten's built-in port (-sUSE_SDL=3), and the assets/ directory is preloaded into the virtual filesystem so the existing relative OBJ paths resolve unchanged.

After installing and activating emsdk (./emsdk install latest && ./emsdk activate latest), in a shell where emcc is on PATH:

emcmake cmake -S . -B build-web -DCMAKE_BUILD_TYPE=Release
cmake --build build-web

This produces build-web/render.{html,js,wasm,data}. WebAssembly cannot be loaded over file://, so serve the directory locally:

python -m http.server 8000 -d build-web
# then open http://localhost:8000/render.html

Notes:

• Emscripten's SDL3 port is marked experimental; you'll see a -Wexperimental warning during the link step.
• The renderer uses SDL_CreateRenderer + a streaming SDL_Texture (rather than SDL_GetWindowSurface / SDL_UpdateWindowSurface) so that the same code path works on both desktop SDL3 and the experimental Emscripten port.
• On Windows, wasm-ld.exe and other emsdk binaries are unsigned, so Smart App Control / WDAC can block linking with WinError 4551. Disabling Smart App Control (Settings → Privacy & security → Windows Security → App & browser control) is the typical fix.

• Run the executable to see a sample mesh rendered with transformations and shading.

This project and all files in the repository are dedicated to the public domain under CC0 1.0 Universal. See the LICENSE file for details.