Add bullet-featherstone plugin (#373)

This PR adds a gz-physics-bullet-featherstone-plugin which wraps the Featherstone API of the bullet physics engine. This is created as a separate plugin from gz-physics-bullet-plugin because the API of Bullet's Featherstone dynamics is different enough that there isn't really feature parity or easy interchangeability between them. Users will need to choose whether they are willing to settle for fewer features in exchange for the better performance of Bullet's Featherstone implementation.


Signed-off-by: Louise Poubel <[email protected]>
Signed-off-by: Michael X. Grey <[email protected]>
Signed-off-by: ahcorde <[email protected]>
Signed-off-by: Michael Carroll <[email protected]>
Co-authored-by: Louise Poubel <[email protected]>
Co-authored-by: Alejandro Hernández Cordero <[email protected]>
Co-authored-by: Steve Peters <[email protected]>
Co-authored-by: Michael Carroll <[email protected]>

CMakeLists.txt

@@ -84,7 +84,7 @@ gz_find_package(DART
 # Find bullet for the bullet plugin wrapper
 gz_find_package(GzBullet
   VERSION 2.87
-  REQUIRED_BY bullet
+  REQUIRED_BY bullet bullet-featherstone
   PKGCONFIG bullet
   PKGCONFIG_VER_COMPARISON >=)
 
@@ -101,7 +101,7 @@ set(GZ_PHYSICS_ENGINE_INSTALL_DIR
 # Configure the build
 #============================================================================
 gz_configure_build(QUIT_IF_BUILD_ERRORS
-  COMPONENTS sdf heightmap mesh dartsim tpe bullet)
+  COMPONENTS sdf heightmap mesh dartsim tpe bullet bullet-featherstone)
 
 
 #============================================================================

README.md

@@ -73,7 +73,7 @@ See the [installation tutorial](https://gazebosim.org/api/physics/5.0/installati
 
 # Usage
 
-Please refer to the [examples directory](https://github.com/gazebosim/gz-physics/raw/ign-physics6/examples/).
+Please refer to the [examples directory](https://github.com/gazebosim/gz-physics/raw/gz-physics6/examples/).
 
 # Documentation
 
@@ -90,7 +90,7 @@ You can also generate the documentation from a clone of this repository by follo
 2. Clone the repository
 
     ```
-    git clone https://github.com/gazebosim/gz-physics -b ign-physics6
+    git clone https://github.com/gazebosim/gz-physics -b gz-physics6 
     ```
 
 3. Configure and build the documentation.

bullet-featherstone/CMakeLists.txt

@@ -0,0 +1,46 @@
+# This component expresses custom features of the bullet plugin, which can
+# expose native bullet data types.
+gz_add_component(bullet-featherstone INTERFACE
+  DEPENDS_ON_COMPONENTS sdf mesh
+  GET_TARGET_NAME features)
+
+link_directories(${BULLET_LIBRARY_DIRS})
+target_link_libraries(${features} INTERFACE GzBullet::GzBullet)
+
+gz_get_libsources_and_unittests(sources test_sources)
+
+# TODO(MXG): Think about an gz_add_plugin(~) macro for ign-cmake
+set(engine_name bullet-featherstone-plugin)
+gz_add_component(${engine_name}
+  SOURCES ${sources}
+  DEPENDS_ON_COMPONENTS bullet-featherstone
+  GET_TARGET_NAME bullet_plugin)
+
+target_link_libraries(${bullet_plugin}
+  PUBLIC
+    ${features}
+    ${PROJECT_LIBRARY_TARGET_NAME}-sdf
+    ${PROJECT_LIBRARY_TARGET_NAME}-mesh
+    gz-common${GZ_COMMON_VER}::gz-common${GZ_COMMON_VER}
+    gz-math${GZ_MATH_VER}::eigen3)
+
+# Note that plugins are currently being installed in 2 places: /lib and the engine-plugins dir
+install(TARGETS ${bullet_plugin} DESTINATION ${GZ_PHYSICS_ENGINE_INSTALL_DIR})
+
+# The library created by `gz_add_component` includes the ign-physics version
+# (i.e. libgz-physics1-name-plugin.so), but for portability,
+# we also install an unversioned symlink into the same versioned folder.
+set(versioned ${CMAKE_SHARED_LIBRARY_PREFIX}${bullet_plugin}${CMAKE_SHARED_LIBRARY_SUFFIX})
+set(unversioned ${CMAKE_SHARED_LIBRARY_PREFIX}${PROJECT_NAME_NO_VERSION_LOWER}-${engine_name}${CMAKE_SHARED_LIBRARY_SUFFIX})
+if (WIN32)
+  # disable MSVC inherit via dominance warning
+  target_compile_options(${bullet_plugin} PUBLIC "/wd4250")
+  INSTALL(CODE "EXECUTE_PROCESS(COMMAND ${CMAKE_COMMAND} -E copy
+      ${GZ_PHYSICS_ENGINE_INSTALL_DIR}\/${versioned}
+      ${GZ_PHYSICS_ENGINE_INSTALL_DIR}\/${unversioned})")
+else()
+  EXECUTE_PROCESS(COMMAND ${CMAKE_COMMAND} -E create_symlink ${versioned} ${unversioned})
+  INSTALL(FILES ${PROJECT_BINARY_DIR}/${unversioned} DESTINATION ${GZ_PHYSICS_ENGINE_INSTALL_DIR})
+endif()
+EXECUTE_PROCESS(COMMAND ${CMAKE_COMMAND} -E create_symlink ${versioned} ${unversioned})
+INSTALL(FILES ${PROJECT_BINARY_DIR}/${unversioned} DESTINATION ${GZ_PHYSICS_ENGINE_INSTALL_DIR})

bullet-featherstone/src/Base.cc

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2022 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+*/
+
+#include "Base.hh"
+
+#include <utility>
+
+namespace gz {
+namespace physics {
+namespace bullet_featherstone {
+
+/////////////////////////////////////////////////
+WorldInfo::WorldInfo(std::string name_)
+  : name(std::move(name_))
+{
+  this->collisionConfiguration =
+    std::make_unique<btDefaultCollisionConfiguration>();
+  this->dispatcher =
+    std::make_unique<btCollisionDispatcher>(collisionConfiguration.get());
+  this->broadphase = std::make_unique<btDbvtBroadphase>();
+  this->solver = std::make_unique<btMultiBodyConstraintSolver>();
+  this->world = std::make_unique<btMultiBodyDynamicsWorld>(
+    dispatcher.get(), broadphase.get(), solver.get(),
+    collisionConfiguration.get());
+
+  btGImpactCollisionAlgorithm::registerAlgorithm(dispatcher.get());
+}
+
+}  // namespace bullet_featherstone
+}  // namespace physics
+}  // namespace gz