Hi Robert,
Once again, thank you for your time.
I continued to look into the scene export issues I was having, and here
are some of my findings (against OSG 3.1.7 development release).
I attached an alternate implementation of
osgDB::Registry::writeNodeImplementation(). The same changes would apply
to other Registry member functions: writeShaderImplementation(),
writeObjectImplementation(), writeImageImplementation(),
writeHeightFieldImplementation(), and possibly read().
One of the major behavior changes is that once ERROR_IN_WRITING_FILE is
encountered, no more attempts are made to write the file. It also
prevents a possible ERROR_IN_WRITING_FILE status from propagating even
though the real error seemed to be FILE_NOT_HANDED. The changes I made
are based on my assumptions about how the plugins "should work", but I
may have overlooked something. The point of the changes is to make it so
the export behavior is the same, regardless of whether or not a plugin
DLL was loaded in response to an export request.
Also, per our DLL search path discussion, the following DLL paths are
searched when attempting to export a model to "osg.txt" (where txt is an
unregistered extension that is not associated with any plugins):
1. Executable folder: [path to application
binary]\osgPlugins-3.1.7\osgdb_txt.dll ...
2. Location of osgDB DLL: [path to osgDB
DLL]\osgPlugins-3.1.7\osgdb_txt.dll ...
3. System 32 folder: C:\Windows\system32\osgPlugins-3.1.7\osgdb_txt.dll ...
4. System folder: C:\Windows\System\osgPlugins-3.1.7\osgdb_txt.dll ...
5. Windows folder: C:\Windows\osgPlugins-3.1.7\osgdb_txt.dll ...
6. Working directory: .\osgPlugins-3.1.7\osgdb_txt.dll ...
7. Folders specified in PATH env var: [PATH
...]\osgPlugins-3.1.7\osgdb_txt.dll ...
[Repeat list, but omit osgPlugins-* portion of that path]
I ended up loading all of the OSG plugin DLLs I plan to use manually and
calling osgDB::Registry::instance ()->setLibraryFilePathList
(std::string ()); early during application startup to prevent the
traversal of the above search paths. I cannot speak for other platforms,
but for Microsoft Windows environments, the default plugin DLL loading
behavior does not seem suitable for production environments.
Regards,
Judson
ReaderWriter::WriteResult Registry::writeNodeImplementation(const Node&
node,const std::string& fileName,const Options* options)
{
// storage for a ReaderWriter result.
ReaderWriter::WriteResult
result(ReaderWriter::WriteResult::FILE_NOT_HANDLED);
// now look for a plug-in to save the file.
std::string libraryName = createLibraryNameForFile(fileName);
(void) loadLibrary(libraryName);
// attempt to write the file from ReaderWriter(s).
AvailableReaderWriterIterator itr(_rwList, _pluginMutex);
for(;itr.valid();++itr)
{
ReaderWriter::WriteResult rr = itr->writeNode(node,fileName,options);
if (rr.success() || rr.error ())
{
// rr.status(): FILE_SAVED or ERROR_IN_WRITING_FILE
result = rr;
break;
}
// rr.status(): NOT_IMPLEMENTED or FILE_NOT_HANDLED
}
if (result.message().empty())
{
switch(result.status())
{
case(ReaderWriter::WriteResult::FILE_NOT_HANDLED):
result.message() = "Warning: Write to \""+fileName+"\" not
supported.";
break;
case(ReaderWriter::WriteResult::ERROR_IN_WRITING_FILE):
result.message() = "Warning: Error in writing to
\""+fileName+"\".";
break;
}
}
return result;
}_______________________________________________
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