Clone the Repo

Check out the repo with:

git clone git@github.com:CesiumGS/cesium-native.git

Dependencies

Cesium Native manages its many dependencies using vcpkg. We use vcpkg's manifest mode, in which vcpkg reads the list of Cesium Native's dependencies and installs them. This requires a local installation of vcpkg and some extra arguments to CMake.

vcpkg

After installing vcpkg – usually by cloning it from https://github.com/microsoft/vcpkg – run the proper bootstrap script and set the VCPKG_ROOT environment variable so that Cesium Native's build can find it:

cd vcpkg
./bootstrap-vcpkg.sh
export VCPKG_ROOT=$PWD

vcpkg and CMake

vcpkg hooks into CMake by loading a toolchain file, which is usually used in cross-compilation scenarios. You can specify this on the command line, but this can become a bit verbose as additional vcpkg options get added, so specifying them all in a CMake presets file is an interesting option. There are example preset files in the cmake-presets directory. We haven't included them in their normal spot in the source tree because they can cause some issues with VS Code, but you can copy CMakeUserPresets.cmake to the root of the Cesium Native source tree to use these predefined presets.

Compiling Cesium Native

Compile from command line

Using presets (on Linux):

cp doc/cmake-presets/CMakeUserPresets.json .
cmake --preset=vcpkg-linux -DCMAKE_BUILD_TYPE=Debug
cmake --build build

By hand:

cmake -B build -S . \
    -DCMAKE_TOOLCHAIN_FILE=$VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake \
    -DCESIUM_USE_EZVCPG=OFF

On Windows:

cp doc/cmake-presets/CMakeUserPresets.json .
cmake --preset=vcpkg-windows-vs
cmake --build build --config Debug
cmake --build build --config Release

vcpkg specifies all information about the compilation target in a "triplet". For compiling Cesium Native as a stand-alone, the system defaults will usually work, but consumers of Cesium Native might need something more exotic. For example, one could configure a Windows build with:

cmake -B build -S . \
    -DCMAKE_TOOLCHAIN_FILE=$VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake \
    -DCESIUM_USE_EZVCPG=OFF \
    -DVCPKG_TARGET_TRIPLET=x64-windows-static-md
cmake --build build --config Debug
cmake --build build --config Release

Compile from Visual Studio Code

1) Install the CMake Tools extension. It should prompt you to generate project files from CMake. 2) On Windows, choose Visual Studio 2017 Release - amd64 as the kit to build. Or choose an appropriate kit for your platform. 3) Then press Ctrl-Shift-P and execute the CMake: Build task or press F7.

Compile with any Visual Studio version using CMake generated projects

1) Open the CMake UI (cmake-gui) 2) Under "Where is the source code", point to your repo 3) Specify your output folder in "Where to build the binaries" 4) Click "Configure". 5) Under "Specify the generator for this project", choose the VS version on your system 6) Click Finish, wait for the process to finish 7) Click Generate

Look for cesium-native.sln in your output folder.

Unit tests can also be run from this solution, under the cesium-native-tests project.

Generate Documentation

Install Doxygen.
Run: npm install
Run: cmake --build build --target cesium-native-docs
Open build/doc/html/index.html

Regenerate glTF and 3D Tiles classes

Much of the code in CesiumGltf, Cesium3DTiles, CesiumGltfReader, CesiumGltfWriter, Cesium3DTilesReader, Cesium3DTilesWriter, and CesiumQuantizedMeshTerrain is generated from the standards' JSON Schema specifications. To regenerate the code:

Make sure you have a relatively recent version of Node.js installed.
Install dependencies by running:

npm install
cd tools/generate-classes
npm install
cd ../..

From the repo root directory, run these commands
- npm run generate-gltf
- npm run generate-3d-tiles
- npm run generate-quantized-mesh-terrain
On Windows, the line endings of the generated files will be different than those checked into the repo. Just git add them and git will fix the line endings (no need to commit).

Regenerate Dependency Graphs

The dependency graphs used in the Cesium Native documentation are generated using a script that parses CMake's GraphViz output and generates a set of Mermaid diagrams. To regenerate the graphs:

Make sure you have a relatively recent version of Node.js installed.
Install dependencies by running:
cd tools/dep-graph-gen

npm install
From the tools/dep-graph-gen directory, run npm run generate-dep-graph to regenerate the graphs.

Run clang-tidy

We use clang-tidy to help improve the quality of the code, and an automated process that runs on every commit ensures that there are no clang-tidy warnings or errors. To run it locally, follow the instructions for your system.

Windows

It's recommended to use WSL2 to run clang-tidy on Windows. The following instructions cover using clang-tidy through Visual Studio 2022's CMake support. To set up clang-tidy on WSL2, follow the Linux instructions below.

Install clang-tidy for Windows. This can be obtained from the installer on the LLVM GitHub releases page. Download LLVM-19.x.x-win64.exe and run the installer.
clang-tidy requires a compile_commands.json file to be generated in the build directory in order to run. This file is only generated with the cmake Ninja or Unix Makefile generators. Visual Studio 2022's CMake support uses the Ninja generator. Open the Cesium Native cmake project with Visual Studio 2022.
Right click on the root CMakeLists.txt and select "CMake Settings for cesium-native"
Specify the path to the installed clang-tidy.exe under "CMake command arguments":
Under "CMake variables and cache", check CESIUM_ENABLE_CLANG_TIDY_ON_BUILD:
Build cesium-native through Visual Studio 2022 as normal. clang-tidy will be invoked for each build command and its warnings and errors will appear in the build output.

Linux

To get clang-tidy, install llvm 19+. For Debian-based systems, LLVM provides an easy install script:

wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
sudo ./llvm.sh 19

Binaries and source releases for use with other platforms can be downloaded from the LLVM GitHub releases page.

cmake should detect the installed clang-tidy-19 automatically, so the project can be configured normally:

cmake -B build -S .

Next, we run the clang-tidy target of Cesium Native's cmake build, which will run clang-tidy. clang-tidy produces a lot of not-very-useful output, so we send it to a file instead of the console:

cmake --build build --target clang-tidy > clang-tidy.log

Finally, we use sed to extract the errors and warnings from the log:

sed -n '/error:/,/^$/p' clang-tidy.log

sed -n '/warning:/,/^$/p' clang-tidy.log

macOS

To get clang-tidy, install llvm 19+. The easiest way is via Homebrew:

brew install llvm

Installing llvm via Homebrew does not add it to your path, so that it doesn't conflict with Xcode. So, we need to specify its location explicitly when running cmake Cesium Native's configure for use with clang-tidy:

cmake -B build -S . -DCLANG_TIDY_PATH=$(brew --prefix llvm)/bin/clang-tidy -DCLANG_TIDY_RUNNER_PATH=$(brew --prefix llvm)/bin/run-clang-tidy

Next, we run the clang-tidy target of Cesium Native's cmake build, which will run clang-tidy. clang-tidy produces a lot of not-very-useful output, so we send it to a file instead of the console: