dist: Use Panda loader system for converting models to .bam

Set bam_model_extensions in order to specify which formats are automatically converted to .bam

Fixes #714

direct/src/dist/commands.py

@@ -67,6 +67,44 @@ def _parse_dict(input):
     return d
 
 
+def _register_python_loaders():
+    # We need this method so that we don't depend on direct.showbase.Loader.
+    if getattr(_register_python_loaders, 'done', None):
+        return
+
+    _register_python_loaders.done = True
+
+    try:
+        import pkg_resources
+    except ImportError:
+        return
+
+    registry = p3d.LoaderFileTypeRegistry.getGlobalPtr()
+
+    for entry_point in pkg_resources.iter_entry_points('panda3d.loaders'):
+        registry.register_deferred_type(entry_point)
+
+
+def _model_to_bam(_build_cmd, srcpath, dstpath):
+    if dstpath.endswith('.gz') or dstpath.endswith('.pz'):
+        dstpath = dstpath[:-3]
+    dstpath = dstpath + '.bam'
+
+    src_fn = p3d.Filename.from_os_specific(srcpath)
+    dst_fn = p3d.Filename.from_os_specific(dstpath)
+
+    _register_python_loaders()
+
+    loader = p3d.Loader.get_global_ptr()
+    options = p3d.LoaderOptions(p3d.LoaderOptions.LF_report_errors |
+                                p3d.LoaderOptions.LF_no_ram_cache)
+    node = loader.load_sync(src_fn, options)
+    if not node:
+        raise IOError('Failed to load model: %s' % (srcpath))
+
+    if not p3d.NodePath(node).write_bam_file(dst_fn):
+        raise IOError('Failed to write .bam file: %s' % (dstpath))
+
 
 def egg2bam(_build_cmd, srcpath, dstpath):
     if dstpath.endswith('.gz') or dstpath.endswith('.pz'):
@@ -259,6 +297,7 @@ class build_apps(setuptools.Command):
             'https://archive.panda3d.org/thirdparty',
         ]
         self.file_handlers = {}
+        self.bam_model_extensions = []
         self.exclude_dependencies = [
             # Windows
             'kernel32.dll', 'user32.dll', 'wsock32.dll', 'ws2_32.dll',
@@ -414,6 +453,15 @@ class build_apps(setuptools.Command):
         for glob in self.exclude_dependencies:
             glob.case_sensitive = False
 
+        # bam_model_extensions registers a 2bam handler for each given extension.
+        # They can override a default handler, but not a custom handler.
+        if self.bam_model_extensions:
+            for ext in self.bam_model_extensions:
+                ext = '.' + ext.lstrip('.')
+                assert ext not in self.file_handlers, \
+                    'Extension {} occurs in both file_handlers and bam_model_extensions!'.format(ext)
+                self.file_handlers[ext] = _model_to_bam
+
         tmp = self.default_file_handlers.copy()
         tmp.update(self.file_handlers)
         self.file_handlers = tmp