fix #5857

setup.py

@@ -23,6 +23,7 @@ def find_version():
         return version_major[0] + "." + version_minor[0] + "." + ncnn_version
     raise RuntimeError("Unable to find version string.")
 
+
 # Parse environment variables
 Vulkan_LIBRARY = os.environ.get("Vulkan_LIBRARY", "")
 CMAKE_TOOLCHAIN_FILE = os.environ.get("CMAKE_TOOLCHAIN_FILE", "")
@@ -38,11 +39,13 @@ def find_version():
 ENABLE_ARC = os.environ.get("ENABLE_ARC", "")
 ENABLE_VISIBILITY = os.environ.get("ENABLE_VISIBILITY", "")
 
+
 # Parse variables from command line with setup.py install
 class InstallCommand(install):
     user_options = install.user_options + [
-        ('vulkan=', None, 'Enable the usage of Vulkan.'),
+        ("vulkan=", None, "Enable the usage of Vulkan."),
     ]
+
     def initialize_options(self):
         install.initialize_options(self)
         self.vulkan = None
@@ -53,6 +56,7 @@ def finalize_options(self):
     def run(self):
         install.run(self)
 
+
 # Convert distutils Windows platform specifiers to CMake -A arguments
 PLAT_TO_CMAKE = {
     "win32": "Win32",
@@ -61,6 +65,7 @@ def run(self):
     "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.
 # If you need multiple extensions, see scikit-build.
@@ -88,13 +93,16 @@ def build_extension(self, ext):
         # Set Python_EXECUTABLE instead if you use PYBIND11_FINDPYTHON
         # EXAMPLE_VERSION_INFO shows you how to pass a value into the C++ code
         # from Python.
+        enable_vulkan = "ON"
+        if Vulkan_LIBRARY == "":
+            enable_vulkan = "OFF"
         cmake_args = [
             "-DCMAKE_LIBRARY_OUTPUT_DIRECTORY={}".format(extdir),
             "-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_RELEASE={}".format(extdir),
             "-DPYTHON_EXECUTABLE={}".format(sys.executable),
             "-DCMAKE_BUILD_TYPE={}".format(cfg),  # not used on MSVC, but no harm
             "-DNCNN_PYTHON=ON",
-            "-DNCNN_VULKAN=ON",
+            "-DNCNN_VULKAN={}".format(enable_vulkan),
             "-DNCNN_DISABLE_RTTI=OFF",
             "-DNCNN_DISABLE_EXCEPTION=OFF",
             "-DNCNN_BUILD_BENCHMARK=OFF",
@@ -208,5 +216,5 @@ def build_extension(self, ext):
     package_dir={"": "python"},
     install_requires=requirements,
     ext_modules=[CMakeExtension("ncnn")],
-    cmdclass={'install': InstallCommand, "build_ext": CMakeBuild},
+    cmdclass={"install": InstallCommand, "build_ext": CMakeBuild},
 )