Move python bindings from pybind11 to nanobind (#61)

* update ps to latest

* update eigen

* core nanobind switchover completed, tests pass locally

* update some comments

Author: nmwsharp

.gitmodules

@@ -1,9 +1,9 @@
-[submodule "deps/pybind11"]
-	path = deps/pybind11
-	url = https://github.com/pybind/pybind11.git
 [submodule "deps/polyscope"]
 	path = deps/polyscope
 	url = https://github.com/nmwsharp/polyscope.git
 [submodule "deps/eigen"]
 	path = deps/eigen
 	url = https://gitlab.com/libeigen/eigen.git
+[submodule "deps/nanobind"]
+	path = deps/nanobind
+	url = https://github.com/wjakob/nanobind

CMakeLists.txt

@@ -1,20 +1,37 @@
 cmake_minimum_required(VERSION 3.15.0) # minimum imposed by scikit-build-core
 project(polyscope LANGUAGES CXX)
 
+# Default to release build
+if (NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+  set(CMAKE_BUILD_TYPE Release CACHE STRING "Choose the type of build." FORCE)
+  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release" "MinSizeRel" "RelWithDebInfo")
+endif()
+
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+set(CMAKE_CXX_STANDARD 20)
+
 ## Gather dependencies
 
-# Eigen
+# == Eigen
 set(EIGEN3_INCLUDE_DIR "${PROJECT_SOURCE_DIR}/deps/eigen/")
 
-# Recurse in to pybind
-set(PYBIND11_NEWPYTHON ON)
-add_subdirectory(deps/pybind11)
+# == Nanobind
+if (CMAKE_VERSION VERSION_LESS 3.18)
+  set(DEV_MODULE Development)
+else()
+  set(DEV_MODULE Development.Module)
+endif()
 
-# We need polyscope
-set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+# find python version to target for bindings
+find_package(Python 3.9 COMPONENTS Interpreter ${DEV_MODULE} REQUIRED)
+
+# recurse into nanobind
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/deps/nanobind)
+
+# == polyscope
 add_subdirectory(deps/polyscope)
 
-pybind11_add_module(polyscope_bindings 
+nanobind_add_module(polyscope_bindings 
   src/cpp/core.cpp
   src/cpp/surface_mesh.cpp
   src/cpp/point_cloud.cpp
@@ -25,6 +42,7 @@ pybind11_add_module(polyscope_bindings
   src/cpp/floating_quantities.cpp
   src/cpp/implicit_helpers.cpp
   src/cpp/managed_buffer.cpp
+
   src/cpp/imgui.cpp
   src/cpp/implot.cpp
 

deps/eigen

@@ -1,20 +1,12 @@
-#include <pybind11/eigen.h>
-#include <pybind11/numpy.h>
-#include <pybind11/pybind11.h>
-
 #include "Eigen/Dense"
 
 #include "polyscope/camera_view.h"
 #include "polyscope/polyscope.h"
 
 #include "utils.h"
 
-namespace py = pybind11;
-namespace ps = polyscope;
-
-
 // clang-format off
-void bind_camera_view(py::module& m) {
+void bind_camera_view(nb::module_& m) {
 
   // == Helper quantity classes
 
@@ -40,9 +32,9 @@ void bind_camera_view(py::module& m) {
 
   // Static adders and getters
   m.def("register_camera_view", &ps::registerCameraView,
-      py::arg("name"), py::arg("parameters"), "Register a camera view", py::return_value_policy::reference);
+      nb::arg("name"), nb::arg("parameters"), "Register a camera view", nb::rv_policy::reference);
   m.def("remove_camera_view", &ps::removeCameraView, "Remove a camera view by name");
-  m.def("get_camera_view", &ps::getCameraView, "Get a camera view by name", py::return_value_policy::reference);
+  m.def("get_camera_view", &ps::getCameraView, "Get a camera view by name", nb::rv_policy::reference);
   m.def("has_camera_view", &ps::hasCameraView, "Check for a camera view by name");
 
 }