Reverting all the adventures into working

.github/workflows/ci.yaml

@@ -20,12 +20,13 @@ jobs:
         python-version: '3.10'
     - name: Build and Install
       run: |
-        python3 -m pip install pybind11
+        python3 -m pip install pybind11[global]
         python3 -m pip install pytest
         python3 -m pip install --verbose .
 
     - name: Test
       run: |
-        source .venv/bin/activate
+        export PATH="/opt/drake/bin${PATH:+:${PATH}}"
+        export PYTHONPATH="/opt/drake/lib/python$(python3 -c 'import sys; print("{0}.{1}".format(*sys.version_info))')/site-packages${PYTHONPATH:+:${PYTHONPATH}}"
         export LD_LIBRARY_PATH="/opt/drake/lib:$LD_LIBRARY_PATH"
         python3 -m pytest

CMakeLists.txt

@@ -6,17 +6,11 @@ cmake_minimum_required(VERSION 3.16...3.27)
 
 # Scikit-build-core sets these values for you, or you can just hard-code the
 # name and version.
-project(
-  ${SKBUILD_PROJECT_NAME}
-  VERSION ${SKBUILD_PROJECT_VERSION}
-  LANGUAGES CXX)
+project(drake_extension LANGUAGES CXX)
 
 include(CTest)
-
+option(RUN_X11_TESTS "Run tests that require X11" OFF)
 find_package(drake CONFIG REQUIRED)
-
-# Try to import all Python components potentially needed by nanobind
-find_package(Python3 REQUIRED COMPONENTS Interpreter Development.Module)
 find_package(pybind11 CONFIG REQUIRED)
 
 execute_process(COMMAND ${Python3_EXECUTABLE}-config --exec-prefix
@@ -38,12 +32,6 @@ set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
 # Add a library using FindPython's tooling (pybind11 also provides a helper like
 # this)
-pybind11_add_module(drake_extension_ext MODULE src/drake_extension_ext.cpp)
-target_link_libraries(drake_extension_ext PUBLIC drake::drake)
-set_target_properties(drake_extension_ext PROPERTIES CXX_VISIBILITY_PRESET default)
-
-# This is passing in the version as a define just as an example
-target_compile_definitions(drake_extension_ext PRIVATE VERSION_INFO=${PROJECT_VERSION})
-
-# Install directive for scikit-build-core
-install(TARGETS drake_extension_ext LIBRARY DESTINATION drake_extension)
+pybind11_add_module(drake_extension MODULE src/drake_extension.cpp)
+target_link_libraries(drake_extension PUBLIC drake::drake)
+set_target_properties(drake_extension PROPERTIES CXX_VISIBILITY_PRESET default)

setup.py

@@ -7,6 +7,14 @@
 from setuptools import Extension, setup
 from setuptools.command.build_ext import build_ext
 
+# Convert distutils Windows platform specifiers to CMake -A arguments
+PLAT_TO_CMAKE = {
+    "win32": "Win32",
+    "win-amd64": "x64",
+    "win-arm32": "ARM",
+    "win-arm64": "ARM64",
+}
+
 
 # A CMakeExtension needs a sourcedir instead of a file list.
 # The name must be the _single_ output extension from the CMake build.
@@ -68,6 +76,26 @@ def build_extension(self, ext: CMakeExtension) -> None:
                 except ImportError:
                     pass
 
+        else:
+            # Single config generators are handled "normally"
+            single_config = any(x in cmake_generator for x in {"NMake", "Ninja"})
+
+            # CMake allows an arch-in-generator style for backward compatibility
+            contains_arch = any(x in cmake_generator for x in {"ARM", "Win64"})
+
+            # Specify the arch if using MSVC generator, but only if it doesn't
+            # contain a backward-compatibility arch spec already in the
+            # generator name.
+            if not single_config and not contains_arch:
+                cmake_args += ["-A", PLAT_TO_CMAKE[self.plat_name]]
+
+            # Multi-config generators have a different way to specify configs
+            if not single_config:
+                cmake_args += [
+                    f"-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_{cfg.upper()}={extdir}"
+                ]
+                build_args += ["--config", cfg]
+
         if sys.platform.startswith("darwin"):
             # Cross-compile support for macOS - respect ARCHFLAGS if set
             archs = re.findall(r"-arch (\S+)", os.environ.get("ARCHFLAGS", ""))
@@ -102,11 +130,12 @@ def build_extension(self, ext: CMakeExtension) -> None:
     version="0.0.1",
     author="M. Amin Safavi",
     author_email="[email protected]",
-    description="A test project using pybind11 and Drake",
+    description="A template project to extend Drake using pybind11 and CMake",
     long_description="",
     ext_modules=[CMakeExtension("drake_extension")],
     cmdclass={"build_ext": CMakeBuild},
     zip_safe=False,
-    extras_require={"test": ["pytest>=6.0"]},
+    extras_require={"test": ["pytest>=6.0"],
+                    "pydrake": ["pydrake>=1.20"]},
     python_requires=">=3.10",
 )

src/drake_extension.cpp

@@ -0,0 +1,51 @@
+/**
+ * @file
+ * Provides an example of creating a simple Drake C++ system and binding it in
+ * pybind11, to be used with pydrake.
+ */
+#include <pybind11/pybind11.h>
+#include <drake/systems/framework/leaf_system.h>
+
+namespace py = pybind11;
+
+using drake::systems::BasicVector;
+using drake::systems::Context;
+using drake::systems::LeafSystem;
+using drake::systems::kVectorValued;
+
+namespace drake_extension {
+
+/// Adds a constant to an input.
+template <typename T>
+class SimpleAdder : public LeafSystem<T> {
+ public:
+  explicit SimpleAdder(T add)
+      : add_(add) {
+    this->DeclareInputPort("in", kVectorValued, 1);
+    this->DeclareVectorOutputPort(
+        "out", BasicVector<T>(1), &SimpleAdder::CalcOutput);
+  }
+
+ private:
+  void CalcOutput(const Context<T>& context, BasicVector<T>* output) const {
+    auto u = this->get_input_port(0).Eval(context);
+    auto&& y = output->get_mutable_value();
+    y.array() = u.array() + add_;
+  }
+
+  const T add_{};
+};
+
+
+PYBIND11_MODULE(drake_extension , m) {
+  m.doc() = "Example module interfacing with pydrake and Drake C++";
+
+  py::module::import("pydrake.systems.framework");
+
+  using T = double;
+
+  py::class_<SimpleAdder<T>, LeafSystem<T>>(m, "SimpleAdder")
+      .def(py::init<T>(), py::arg("add"));
+}
+
+}  // namespace drake_extension

tests/test_simple_adder.py

@@ -1,4 +1,4 @@
-#import numpy as np
+import numpy as np
 from drake_extension import SimpleAdder
 
 from pydrake.systems.analysis import Simulator