SCons: Add emitter to declutter build objects

methods.py

@@ -16,8 +16,7 @@ from typing import Generator, List, Optional, Union, cast
 from misc.utility.color import print_error, print_info, print_warning
 
 # Get the "Godot" folder name ahead of time
-base_folder_path = str(os.path.abspath(Path(__file__).parent)) + "/"
-base_folder_only = os.path.basename(os.path.normpath(base_folder_path))
+base_folder = Path(__file__).resolve().parent
 
 compiler_version_cache = None
 
@@ -83,6 +82,29 @@ def add_source_files(self, sources, files, allow_gen=False):
     return True
 
 
+def redirect_emitter(target, source, env):
+    """
+    Emitter to automatically redirect object/library build files to the `bin/obj` directory,
+    retaining subfolder structure. External build files will attempt to retain subfolder
+    structure relative to their environment's parent directory, sorted under `bin/obj/external`.
+    If `redirect_build_objects` is `False`, or an external build file isn't relative to the
+    passed environment, this emitter does nothing.
+    """
+    if not env["redirect_build_objects"]:
+        return target, source
+
+    redirected_targets = []
+    for item in target:
+        if base_folder in (path := Path(item.get_abspath()).resolve()).parents:
+            item = env.File(f"#bin/obj/{path.relative_to(base_folder)}")
+        elif (alt_base := Path(env.Dir(".").get_abspath()).resolve().parent) in path.parents:
+            item = env.File(f"#bin/obj/external/{path.relative_to(alt_base)}")
+        else:
+            print_warning(f'Failed to redirect "{path}"')
+        redirected_targets.append(item)
+    return redirected_targets, source
+
+
 def disable_warnings(self):
     # 'self' is the environment
     if self.msvc and not using_clang(self):
@@ -150,7 +172,7 @@ def get_version_info(module_version_string="", silent=False):
 
 
 def get_git_info():
-    os.chdir(base_folder_path)
+    os.chdir(base_folder)
 
     # Parse Git hash if we're in a Git repo.
     git_hash = ""
@@ -775,7 +797,7 @@ def show_progress(env):
     if env["ninja"]:
         return
 
-    NODE_COUNT_FILENAME = f"{base_folder_path}.scons_node_count"
+    NODE_COUNT_FILENAME = base_folder / ".scons_node_count"
 
     class ShowProgress:
         def __init__(self):