To build webrays and the examples you will at least need something like the following command, depending on your distro's package manager.
apt-get install build-essential cmake libsdl2-dev
Next, we will require a build of ANGLE. Follow the instructions from ANGLE's repository to build ANGLE from source. Make sure to build a shared version with is_component_build = false in order to link dependencies into the build targets.
With SDL2 and ANGLE installed we simply point our console to the cloned webrays folder and execute
cmake -S . -B build -DBUILD_EXAMPLES=1 -DEGL_LIBRARY=path/to/ANGLE/libEGL.so -DGLES_LIBRARY=path/to/ANGLE/libGLESv2.so -DCMAKE_BUILD_TYPE=Release
Alternatively, you can use a precompiled version of ANGLE. For example if you happen to have Visual Studio Code installed, it already comes with a compiled version of ANGLE.
cmake -S . -B build -DBUILD_EXAMPLES=1 -DEGL_LIBRARY=/usr/share/code/libEGL.so -DGLES_LIBRARY=/usr/share/code/libGLESv2.so -DCMAKE_BUILD_TYPE=Release
Build with
cmake --build build --config Release
Finally, install with
cmake --install build --config Release
If you prefer a non-default installation path, you can pass -DCMAKE_INSTALL_PREFIX=/custom/install/path to the first cmake command.
After building or installing, it is very easy to use webrays in your own application. An important aspect that you need to consider is that your application and webrays need to use the same libGLESv2 library from ANGLE in order to properly work on the same context. This is easily taken care of by accordingly setting the rpath during compilation.
For example, the hello_triangle example can be manually built using the following command
clang hello_triangle.c -Wl,-rpath,\$ORIGIN -I /usr/include/SDL2 -I/custom/install/path/webrays/include -o hello_triangle -L/custom/install/path/webrays/lib -lSDL2 -lEGL -lGLESv2 -lwebrays