Link Fx2Dlib

Fx2D’s CMake project creates one static-library target: Fx2Dlib. Link your executable to that target; its public include path and required Eigen/yaml-cpp dependencies propagate through the target.

Fx2D does not currently export an installed package configuration, so this will not work yet:

find_package(Fx2D CONFIG REQUIRED) # not available

Instead, add the source tree to your CMake build.

Add a checked-out copy

# Your CMakeLists.txt
set(FX2D_HEADLESS ON CACHE BOOL "Build Fx2D without raylib/ImGui" FORCE)
set(FX2D_BUILD_TESTS OFF CACHE BOOL "Skip Fx2D's test executable" FORCE)
add_subdirectory(external/fx2d)

add_executable(my_sim main.cpp)
target_link_libraries(my_sim PRIVATE Fx2Dlib)

Use FX2D_HEADLESS=ON for simulations, CI, and tooling. It excludes Renderer.cpp, the viewer executable, and visual examples; raylib and ImGui are not needed.

Fetch with CMake

include(FetchContent)

set(FX2D_HEADLESS ON CACHE BOOL "" FORCE)
set(FX2D_BUILD_TESTS OFF CACHE BOOL "" FORCE)

FetchContent_Declare(
  fx2d
  GIT_REPOSITORY https://github.com/Bharath2/fx2d-physics-engine.git
  GIT_TAG main # Prefer a pinned commit in reproducible projects.
)
FetchContent_MakeAvailable(fx2d)

add_executable(my_sim main.cpp)
target_link_libraries(my_sim PRIVATE Fx2Dlib)

Enable the renderer

For a visual application, leave FX2D_HEADLESS off:

set(FX2D_HEADLESS OFF CACHE BOOL "" FORCE)
set(FX2D_BUILD_TESTS OFF CACHE BOOL "" FORCE)
add_subdirectory(external/fx2d)

add_executable(my_viewer main.cpp)
target_link_libraries(my_viewer PRIVATE Fx2Dlib)

Before configuring, populate Fx2D’s placeholder lib/imgui/ and lib/rlImGui/ directories with their upstream source files. The renderer build also needs raylib, yaml-cpp, and Eigen3 discoverable by CMake. The top-level installation guide has the full dependency list.

Build options

Option	Default	Effect
FX2D_HEADLESS	OFF	Remove raylib/ImGui renderer code and visual examples.
FX2D_BUILD_TESTS	ON	Build the Fx2DTests CTest executable.
FX2D_BUILD_EXAMPLES	OFF	Build visual sample targets. Mutually exclusive with headless mode.
FX2D_BUILD_BENCH	OFF	Build the Fx2DBench headless benchmark.
FX2D_WARNINGS	ON	Enable the project’s higher compiler warning level.
FX2D_WERROR	OFF	Treat warnings as errors.

See header selection for what your application should include once it links Fx2Dlib.