Add example mixing C++/Python

Author: JafarAbdi

CMakeLists.txt

@@ -49,7 +49,12 @@ pybind11_add_module(behaviortree_py src/bindings/behaviortree_py.cpp)
 target_compile_features(behaviortree_py PRIVATE cxx_std_20)
 target_link_libraries(behaviortree_py PRIVATE ${PROJECT_NAME}_lib)
 
-install(TARGETS behaviortree_py
+pybind11_add_module(example src/example.cpp)
+target_compile_features(example PRIVATE cxx_std_20)
+target_compile_definitions(example PRIVATE BT_PLUGIN_EXPORT)
+target_link_libraries(example PRIVATE ${PROJECT_NAME}_lib)
+
+install(TARGETS behaviortree_py example
         LIBRARY DESTINATION ${PYTHON_INSTALL_DIR}/behaviortree_py)
 
 # ##############################################################################

README.md

@@ -42,7 +42,7 @@ bt.load_type_converters(
 
 ## Limitations
 
-- Only `register_simple_action`, `register_simple_condition`, and `register_simple_decorator` are supported.
+- Only `register_simple_action`, `register_simple_condition`, and `register_simple_decorator` are currently supported.
 - Due to limitations of `BT::Any` only copy-constructible types are supported.
 - Due to how `pybind11` handle memory, mixing `std::shared_ptr` and `std::unique_ptr` between python/c++ is not supported.
 

examples/bt_example_custom.py

@@ -0,0 +1,53 @@
+import time
+
+import behaviortree_py as bt
+import behaviortree_py.example as bt_example  # Needed to laod the ExampleTask pybind11
+
+xml_text = """
+<root BTCPP_format="4">
+    <BehaviorTree ID="MainTree">
+        <Sequence>
+            <SetTaskName task="{task}" />
+            <ModifyTaskName task="{task}" />
+            <PrintTaskName task="{task}" />
+            <PySetTaskName task="{task}" />
+            <PrintTaskName task="{task}" />
+        </Sequence>
+    </BehaviorTree>
+</root>
+"""
+
+
+def modify_task_name(tree_node: bt.TreeNode) -> bt.NodeStatus:
+    task = tree_node.get_input("task")
+    print(f"Modifying task name: {task.name}")
+    task.name = "My Task Python"
+    tree_node.set_output("task", task)
+    return bt.NodeStatus.SUCCESS
+
+
+def py_set_task_name(tree_node: bt.TreeNode) -> bt.NodeStatus:
+    task = bt_example.ExampleTask()
+    task.name = "New Task Name Python"
+    tree_node.set_output("task", task)
+    return bt.NodeStatus.SUCCESS
+
+
+factory = bt.BehaviorTreeFactory()
+factory.register_from_plugin(bt_example.__file__)
+bt.load_type_converters(bt_example.__file__)
+factory.register_simple_action(
+    "ModifyTaskName", modify_task_name, dict([bt.bidirectional_port("task")])
+)
+factory.register_simple_action(
+    "PySetTaskName", py_set_task_name, dict([bt.output_port("task")])
+)
+factory.register_behavior_tree_from_text(xml_text)
+
+tree = factory.create_tree("MainTree")
+
+logger = bt.StdCoutLogger(tree)
+
+print(bt.get_tree_recursively(tree.root_node()))
+
+tree.tick_while_running()

src/bindings/behaviortree_py.cpp

@@ -55,6 +55,7 @@ PYBIND11_MODULE(behaviortree_py, m) {
       .def("register_behavior_tree_from_text",
            &BT::BehaviorTreeFactory::registerBehaviorTreeFromText,
            py::arg("xml_text"))
+      .def("register_from_plugin", &BT::BehaviorTreeFactory::registerFromPlugin, py::arg("file_path"))
       .def("register_scripting_enum", &BT::BehaviorTreeFactory::registerScriptingEnum)
       .def(
           "register_simple_action",
@@ -116,6 +117,7 @@ PYBIND11_MODULE(behaviortree_py, m) {
       },
       py::arg("root_tree"));
 
+  m.def("get_registered_converters", &get_registered_converters);
   m.def(
        "input_port",
        [](BT::StringView name, BT::StringView description) { return BT::InputPort<BT::Any>(name, description); },

src/example.cpp

@@ -0,0 +1,52 @@
+#include <behaviortree_cpp/action_node.h>
+#include <behaviortree_cpp/bt_factory.h>
+#include <fmt/format.h>
+#include <pybind11/pybind11.h>
+
+#include <behaviortree_py/behaviortree_py.hpp>
+
+struct ExampleTask {
+  std::string name;
+};
+
+class SetTaskName : public BT::SyncActionNode {
+ public:
+  SetTaskName(const std::string& name, const BT::NodeConfig& config) : SyncActionNode(name, config) {}
+
+  static BT::PortsList providedPorts() { return {BT::OutputPort<ExampleTask>("task")}; }
+
+  BT::NodeStatus tick() override {
+    auto task = ExampleTask();
+    task.name = "My Task C++";
+    setOutput("task", task);
+    return BT::NodeStatus::SUCCESS;
+  }
+};
+
+class PrintTaskName : public BT::SyncActionNode {
+ public:
+  PrintTaskName(const std::string& name, const BT::NodeConfig& config) : SyncActionNode(name, config) {}
+
+  static BT::PortsList providedPorts() { return {BT::InputPort<ExampleTask>("task")}; }
+
+  BT::NodeStatus tick() override {
+    auto task_maybe = getInput<ExampleTask>("task");
+    if (!task_maybe) {
+      log_error("Missing required input [task]");
+      return BT::NodeStatus::FAILURE;
+    }
+    log_info(fmt::format("Task name: {}", task_maybe.value().name));
+    return BT::NodeStatus::SUCCESS;
+  }
+};
+
+namespace py = pybind11;
+PYBIND11_MODULE(example, m) {
+  py::class_<ExampleTask>(m, "ExampleTask").def(py::init<>()).def_readwrite("name", &ExampleTask::name);
+}
+
+BT_REGISTER_NODES(factory) {
+  factory.registerNodeType<SetTaskName>("SetTaskName");
+  factory.registerNodeType<PrintTaskName>("PrintTaskName");
+}
+BT_REGISTER_TYPE_CONVERTER(ExampleTask);