--- projects/Rigid/CMakeLists.txt.orig	2024-09-30 13:46:54 UTC
+++ projects/Rigid/CMakeLists.txt
@@ -1,11 +1,20 @@
 add_definitions(-DBT_THREAD_SAFE)
 add_compile_options(-w)
 
-if (NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/bullet3/CMakeLists.txt)
+# FreeBSD: use system bullet (devel/bullet) instead of the bundled copy
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(BULLET REQUIRED bullet)
+
+# Parts of zenustech/bullet3 fork which are not provided by devel/bullet
+if (NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/bullet3/src/URDFImporter/CMakeLists.txt)
     message(FATAL_ERROR "bullet3 submodule not found! Please run: git submodule update --init --recursive")
 endif()
-add_subdirectory(bullet3)
-add_subdirectory(bullet3/HACD)
+file (GLOB ZEN_BULLET_EXTRAS_SOURCE
+    bullet3/src/BulletInverseDynamics/*.cpp
+    bullet3/src/BulletInverseDynamics/details/*.cpp
+    bullet3/src/BussIK/*.cpp
+    bullet3/src/VHACD/src/*.cpp
+    bullet3/src/URDFImporter/*.cpp)
 
 file (GLOB ZEN_RIGID_SOURCE *.cpp *.h)
 
@@ -14,18 +23,15 @@
     list (APPEND ZEN_RIGID_SOURCE ${CMAKE_CURRENT_SOURCE_DIR}/RigidFracture.cpp)
 endif(ZENO_WITH_CUDA)
 
-target_sources(zeno PRIVATE ${ZEN_RIGID_SOURCE})
-zeno_disable_warning(${ZEN_RIGID_SOURCE})
+target_sources(zeno PRIVATE ${ZEN_RIGID_SOURCE} ${ZEN_BULLET_EXTRAS_SOURCE})
+zeno_disable_warning(${ZEN_RIGID_SOURCE} ${ZEN_BULLET_EXTRAS_SOURCE})
 target_include_directories(zeno PRIVATE .)
-target_include_directories(zeno PRIVATE bullet3/src)
+target_include_directories(zeno PRIVATE bullet3/src bullet3/src/VHACD)
+target_include_directories(zeno PRIVATE ${BULLET_INCLUDE_DIRS} ${BULLET_INCLUDEDIR}/HACD)
+target_compile_options(zeno PRIVATE ${BULLET_CFLAGS_OTHER})
 
-target_link_libraries(zeno PRIVATE LinearMath)
-target_link_libraries(zeno PRIVATE Bullet3Common)
-target_link_libraries(zeno PRIVATE BulletInverseDynamics)
-target_link_libraries(zeno PRIVATE BulletCollision)
-target_link_libraries(zeno PRIVATE BulletDynamics)
-target_link_libraries(zeno PRIVATE BulletSoftBody)
-target_link_libraries(zeno PRIVATE HACD)
-target_link_libraries(zeno PRIVATE VHACD)
-target_link_libraries(zeno PRIVATE BussIK)
-target_link_libraries(zeno PRIVATE URDFImporter)
+foreach (lib IN ITEMS BulletSoftBody BulletDynamics BulletCollision
+        Bullet3Common LinearMath HACD)
+    find_library(BULLET_${lib}_LIBRARY NAMES ${lib} HINTS ${BULLET_LIBRARY_DIRS} REQUIRED)
+    target_link_libraries(zeno PRIVATE ${BULLET_${lib}_LIBRARY})
+endforeach()