Thrall, Bryan wrote:
When you add an alias, though, aren't you saying to the plugin, "Trust me, even though you don't recognize the file extension, handle it"?
Hi Bryan -- That might be what you're saying, but that's not how osgDB::Registry is interpreting it. :-)
Without aliases at all, Registry forms plugin names from the file extension. If an app tries to load a *.gif file, Registry creates a plugin named "osgdb_gif.xx", tries to load it, then calls into it to load the *.gif file.
Aliases tell Registry how to form the plugin name when an extension is in the alias list. A concrete example is OpenFlight. The Registry constructor registers "flt" as an alias to "OpenFlight". If the app tries to open a *.flt file, Registry finds "flt" in the alias list and knows that the plugin name is "osgdb_openflight.xx".
Bottom line: When you register an alias, you're not talking to the plugin at all. You're talking to the Registry.
It would make sense, IMHO, for osgDB::Registry to add aliases to each plugin's list of handled extensions, and I don't think that would take too much work to do (make ReaderWriter::supportsExtension() public and call it in getReaderWriterForExtension() when it gets to the loaded library).
Many plugins check the extension directly in ReadNode and return FILE_NOT_SUPPORTED if it doesn't match what they expect. What you suggest is possible, but would require you to check and possibly modify every single plugin, and every single read and write entry point in the plugin, to conform to the new behavior.
-Paul _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
