message: Add README section on Filament CMake options
diff: @@ -249,6 +249,28 @@ $ ./build.sh -j release
  If you use CMake directly instead of the build script, pass `-DENABLE_JAVA=OFF` to CMake instead.
  +### Filament-specific CMake Options
  +
  +The following CMake options are boolean options specific to Filament:
  +
  +- `ENABLE_JAVA`: Compile Java projects: requires a JDK and the JAVA_HOME env var
  +- `ENABLE_LTO`: Enable link-time optimizations if supported by the compiler
  +- `FILAMENT_BUILD_FILAMAT`: Build filamat and JNI buildings
  +- `FILAMENT_SUPPORTS_METAL`: Include the Metal backend
  +- `FILAMENT_SUPPORTS_VULKAN`: Include the Vulkan backend
  +- `GENERATE_JS_DOCS`: Build WebGL documentation and tutorials
  +- `INSTALL_BACKEND_TEST`: Install the backend test library so it can be consumed on iOS
  +- `USE_EXTERNAL_GLES3`: Experimental: Compile Filament against OpenGL ES 3
  +
  +To turn an option on or off:
  +
  +```
  +$ cd <cmake-build-directory>
  +$ cmake . -DOPTION=ON # Relace OPTION with the option name, set to ON / OFF
  +```
  +
  +Options can also be set with the CMake GUI.
  +
  ### Linux
  Make sure you've installed the following dependencies:
  