Fix python wheel builds

Author: wjakob

CMakeLists.txt

@@ -578,16 +578,24 @@ if (NANOGUI_BUILD_PYTHON)
   message(STATUS "NanoGUI: building the Python plugin.")
   if (NOT TARGET nanobind::module)
     if (SKBUILD)
+      # Constrain FindPython to find the Python version used by scikit-build
+      set(Python_VERSION "${PYTHON_VERSION_STRING}")
+      set(Python_EXECUTABLE "${PYTHON_EXECUTABLE}")
+      set(Python_INCLUDE_DIR "${PYTHON_INCLUDE_DIR}")
+      set(Python_LIBRARIES "${PYTHON_LIBRARY}")
+
+      find_package(Python COMPONENTS Interpreter Development.Module REQUIRED)
+
       execute_process(
         COMMAND
-        "${PYTHON_EXECUTABLE}" -c
-        "import nanobind; print(nanobind.get_cmake_dir())"
+        "${PYTHON_EXECUTABLE}" -c "import nanobind; print(nanobind.cmake_dir())"
         OUTPUT_VARIABLE _tmp_dir
         OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ECHO STDOUT)
-        list(APPEND CMAKE_PREFIX_PATH "${_tmp_dir}")
+      list(APPEND CMAKE_PREFIX_PATH "${_tmp_dir}")
+
       find_package(nanobind CONFIG REQUIRED)
     else()
-      find_package(Python COMPONENTS Interpreter Development REQUIRED)
+      find_package(Python COMPONENTS Interpreter Development.Module REQUIRED)
 
       # Allow overriding the nanobind library used to compile NanoGUI
       set(NANOGUI_NANOBIND_DIR "${CMAKE_CURRENT_SOURCE_DIR}/ext/nanobind"

README.rst

@@ -1,26 +1,22 @@
 NanoGUI
 ========================================================================================
-|docs| |travis| |appveyor|
+|docs| |gha|
 
 .. |docs| image:: https://readthedocs.org/projects/nanogui/badge/?version=latest
     :target: http://nanogui.readthedocs.org/en/latest/?badge=latest
     :alt: Docs
 
-.. |travis| image:: https://travis-ci.org/wjakob/nanogui.svg?branch=master
-   :target: https://travis-ci.org/wjakob/nanogui
-   :alt: Travis Build Status
-
-.. |appveyor| image:: https://ci.appveyor.com/api/projects/status/m8h3uyvdb4ej2i02/branch/master?svg=true
-   :target: https://ci.appveyor.com/project/wjakob/nanogui/branch/master
-   :alt: Appveyor Build Status
+.. |gha| image:: https://github.com/mitsuba-renderer/nanogui/actions/workflows/build.yml/badge.svg
+   :target: https://github.com/mitsuba-renderer/nanogui/actions/workflows/build.yml
+   :alt: GitHub Actions Build Status
 
 .. begin_brief_description
 
 NanoGUI is a minimalistic cross-platform widget library for OpenGL 3+, GLES
 2/3, and Metal. It supports automatic layout generation, stateful C++ lambdas
 callbacks, a variety of useful widget types and Retina-capable rendering on
 Apple devices thanks to NanoVG_ by Mikko Mononen. Python bindings of all
-functionality are provided using pybind11_. Binary wheels of NanoGUI are
+functionality are provided using nanobind_. Binary wheels of NanoGUI are
 available on PyPI_.
 
 **Note**: This repository contains an improved port of the original NanoGUI_.
@@ -57,7 +53,7 @@ the the repository here incorporates the following changes:
 7. The Entypo_ icon font has been replaced by FontAwesome_ (v5.10.1).
 
 .. _NanoVG: https://github.com/memononen/NanoVG
-.. _pybind11: https://github.com/wjakob/pybind11
+.. _nanobind: https://github.com/wjakob/nanobind
 .. _PyPi: https://pypi.org/project/nanogui
 .. _NanoGUI: https://github.com/wjakob/nanogui
 .. _Tekari: https://rgl.epfl.ch/tekari?url=%2F%2Frgl.s3.eu-central-1.amazonaws.com%2Fmedia%2Fuploads%2Fwjakob%2F2018%2F08%2F27%2Firidescent-paper.txt&log=1

nanogui/__init__.py

@@ -2,7 +2,7 @@
 
 _import('nanogui.nanogui_ext')
 
-def get_cmake_dir():
+def cmake_dir():
     from os import path
     file_dir = path.abspath(path.dirname(__file__))
     cmake_path = path.join(file_dir, "share", "cmake", "nanogui")

pyproject.toml

@@ -1,2 +1,3 @@
 [build-system]
-requires = ["setuptools", "wheel", "scikit-build @ git+https://github.com/scikit-build/scikit-build.git@master", "cmake", "ninja", "nanobind>=0.0.7"]
+requires = ["setuptools", "wheel", "scikit-build", "cmake", "ninja", "nanobind>=0.0.8"]
+build-backend = "setuptools.build_meta"

src/python/widget.cpp

@@ -30,9 +30,19 @@ int widget_tp_traverse_base(PyObject *self, visitproc visit, void *arg, PyTypeOb
             strcmp(name + name_len - suffix_len, suffix) != 0)
             continue;
 
+
+#if PY_VERSION_HEX < 0x03090000
+        PyObject *func = PyObject_GetAttr(self, key),
+                 *result = nullptr;
+        if (func) {
+            result = _PyObject_Vectorcall(func, nullptr, 0, nullptr);
+            Py_DECREF(func);
+        }
+#else
         PyObject *args[] = { self };
         PyObject *result = PyObject_VectorcallMethod(
             key, args, 1 | PY_VECTORCALL_ARGUMENTS_OFFSET, nullptr);
+#endif
 
         if (!result) {
             PyErr_Clear();