Separate the CLI argument parsing from the top-level generate funct…

…ion (#10)

src/generate.py

@@ -189,9 +189,9 @@ class _AssetResult(NamedTuple):
     shaders : List[_Shader]
 
 def _process_asset(
-        gltf_file_path : str,
-        out_dir : Path,
-        skip_codegen : bool = False
+    gltf_file_path : str,
+    out_dir : Path,
+    skip_codegen : bool = False
 ) -> _AssetResult:
     log = io.StringIO()
     log, sys.stdout = sys.stdout, log
@@ -226,49 +226,26 @@ def _process_asset(
     log, sys.stdout = sys.stdout, log
     return _AssetResult(log.getvalue(), per_asset_shaders)
 
-if __name__ == "__main__":
-    parser = argparse.ArgumentParser(
-        description = "Generate shaders from glTF materials."
-    )
-    parser.add_argument("--gltf-dir", help = "Path to the source glTF assets")
-    parser.add_argument("--out-dir", help = "Path to the output directory")
-    parser.add_argument(
-        "--compile",
-        action = 'store_true',
-        help = "Compile the generated shaders with DXC (has to be in PATH)"
-    )
-    parser.add_argument(
-        "--to-glsl",
-        action = 'store_true',
-        help = "Cross-compile to GLSL with SPIRV-Cross"
-    )
-    parser.add_argument(
-        "--skip-codegen",
-        action = 'store_true',
-        help = "Assume that sources have been generated and proceed to "
-               "compilation."
-    )
-    parser.add_argument(
-        "--serial",
-        action = 'store_true',
-        help = "Disable parallelization to facilitate debugging."
-    )
-    args = parser.parse_args()
-
-    gltf_dir_path = Path(args.gltf_dir)
+def generate(
+    gltf_dir_path : Path,
+    out_dir_path : Path,
+    compile : bool,
+    to_glsl : bool,
+    skip_codegen : bool,
+    serial : bool
+):
     if not gltf_dir_path.is_dir():
         raise NotADirectoryError(gltf_dir_path)
-
-    os.makedirs(args.out_dir, exist_ok = True)
-    out_dir = Path(args.out_dir)
+
+    os.makedirs(out_dir_path, exist_ok = True)
 
     shaders = []
-    if args.serial:
+    if serial:
         for gltf_path in gltf_dir_path.glob('**/*.gltf'):
             asset_result = _process_asset(
                 gltf_file_path = gltf_path,
-                out_dir = out_dir,
-                skip_codegen = args.skip_codegen
+                out_dir = out_dir_path,
+                skip_codegen = skip_codegen
             )
             print(asset_result.log)
             shaders += asset_result.shaders
@@ -277,32 +254,70 @@ def _process_asset(
             for asset_result in pool.imap_unordered(
                 functools.partial(
                     _process_asset,
-                    out_dir = out_dir,
-                    skip_codegen = args.skip_codegen
+                    out_dir = out_dir_path,
+                    skip_codegen = skip_codegen
                 ),
                 gltf_dir_path.glob('**/*.gltf')
             ):
                 print(asset_result.log)
                 shaders += asset_result.shaders
 
-    if args.compile:
+    if compile:
         print()
         dxc.identify()
-        if args.to_glsl:
+        if to_glsl:
             spirv_cross.identify()
             glslc.identify()
 
-        if args.serial:
+        if serial:
             for shader in shaders:
-                log = shader.compile(to_glsl = args.to_glsl)
+                log = shader.compile(to_glsl = to_glsl)
                 print(log, end = '')
         else:
             with mp.Pool() as pool:
                 for log in pool.imap_unordered(
                     functools.partial(
                         _compile_shader,
-                        to_glsl = args.to_glsl
+                        to_glsl = to_glsl
                     ),
                     shaders
                 ):
                     print(log, end = '')
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description = "Generate shaders from glTF materials."
+    )
+    parser.add_argument("--gltf-dir", help = "Path to the source glTF assets")
+    parser.add_argument("--out-dir", help = "Path to the output directory")
+    parser.add_argument(
+        "--compile",
+        action = 'store_true',
+        help = "Compile the generated shaders with DXC (has to be in PATH)"
+    )
+    parser.add_argument(
+        "--to-glsl",
+        action = 'store_true',
+        help = "Cross-compile to GLSL with SPIRV-Cross"
+    )
+    parser.add_argument(
+        "--skip-codegen",
+        action = 'store_true',
+        help = "Assume that sources have been generated and proceed to "
+               "compilation."
+    )
+    parser.add_argument(
+        "--serial",
+        action = 'store_true',
+        help = "Disable parallelization to facilitate debugging."
+    )
+    args = parser.parse_args()
+
+    generate(
+        gltf_dir_path = Path(args.gltf_dir),
+        out_dir_path = Path(args.out_dir),
+        compile = args.compile,
+        to_glsl = args.to_glsl,
+        skip_codegen = args.skip_codegen,
+        serial = args.serial
+    )