[osg-users] Determining supported file formats

Paul Martz pmartz at skew-matrix.com
Wed Jul 2 08:06:06 PDT 2008

(For reference, this is a continuation/recap of the thread ".ive plugin:
incorrect ReadResult?" from early May.)
Hi all --
I think it would be useful to add a new OSG application to the core
distribution for determining supported file formats. The output of such an
app might be a list of extensions and whether input or output is supported
for that extension using the Node, Image, Object, and/or HeightField
interfaces in osgDB. Output would vary from one installation to another
based on available plugins.
Based on a lab Bob Kuehne created for our OSG training courses, I have
crafted such an application, and Bob and I are prepared to submit it for
inclusion in core OSG. However, the application relies on plugins being
robust enough to return the expected value when attempting to read an empty
file of a supported type. Currently, many plugins are not robust enough to
meet this requirement.
To explain further: To test the IVE plugin for Node input support, the
application creates an empty .ive file and calls readNode directly on the
plugin's ReaderWriter. Because OSG's IVE plugin supports reading .ive files
into Nodes, the worst return value the app expects to see is
ERROR_IN_READING_FILE. However, the IVE plugin (and many other plugins)
"incorrectly" return FILE_NOT_HANDLED when attempting to read an empty file,
even though the extension is supported.

There are two ways I can proceed to create this app:

1) Submit what I currently have to osg-submissions, and fix issues with the
plugins as they are encountered. I've already fixed some, but more work
remains; this will require community effort. However, I'm optimistic we
could have a viable application in the SIGGRAPH timeframe.

2) I'm interested in suggestions for better ways to write such an
application -- some other technique that doesn't depend on plugins correctly
handling empty files. Any ideas?

If we all decide option 1 is the best way to go, I'll submit my code ASAP.
Just wanted to have a little discussion first and make sure this was the
correct route.
Paul Martz
Skew Matrix Software LLC
http://www.skew-matrix.com <http://www.skew-matrix.com/> 
+1 303 859 9466

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