The gif loader was incorrectly setting pixels as transparent in certain animated gifs. It was ignoring the disposal method value in the extension block and always overwriting the alpha value in each frame. It is common for some animated gifs to set the disposal method so that the previous alpha value is retained. This patch modifies the loader to respect the disposal method flag.
Setting the reference time greater than the duration of a gif would cause a crash. Also, the current reference time is not immediately updated when manually setting the reference time.
a change in version 5.0.0 required a call to the fuction "DGifOpen" to pass an int ref for an error code.
My fix ignores the error, just fixes the compile."
Changes includes:
1. A new GifImageStream class (inherit from osg::ImageStream and OpenThreads::Thread) have already been added to implement different operations of a GIF movie, such like playing, pausing, rewinding, setting time and so on.
2. Some small changes to decode_row() and gif_read_stream(), which make the transparency of GIF images correctly.
3. Just a few changes to the ReaderWriterGIF::readGIFStream() function, which ensure that animate GIFs are loaded by GifImageStream (and the function returns GifImageStream objects) and static GIFs unchanged (still use the old method and returns osg::Image objects!).
Attachments are the cpp file and an animate GIF file for further test. Just rebuild the osgdb_gif project and use osgviewer or osgmovie to view it.
The plugin has been tested on Windows and Arch Linux."
completed the new registration of the plugin-readerwriters
("REGISTER_OSGPLUGIN") according to your osgstaticviewer-example (see
attachment, based on today's svn)."
instead of osgDB::Registry where it original lay. This has been done to allow
fileName strings to be encode data rather than just file names, such as one
requires when using PagedLOD along with plugins for doing dynamic tesselation.
osg::Image::setImage has also been modified to require the AllocationMode
mode to be passed to it so that it knows how to delete the data once the
image goes out of scope.
Port the image plugins across to specify the new AllocationMode, and converted
them across to using new/delete in place of malloc/free.
for settings options in osgDB::Registry, and added the paramter to all of the
reaader/writer plugins. The Options structure by default has an string attached
for packing basic options, however, it also can be subclassed to encapsulate
any users defined option data. In the later case both the client code *and*
the plugin need to be aware of subclass, the plugin will need to use
dynamic_cast<> to assertain its type.
