forcing users to use osgDB::readRef*File() methods. The later is preferable as it closes a potential threading bug when using paging databases in conjunction
with the osgDB::Registry Object Cache. This threading bug occurs when one thread gets an object from the Cache via an osgDB::read*File() call where only
a pointer to the object is passed back, so taking a reference to the object is delayed till it gets reassigned to a ref_ptr<>, but at the same time another
thread calls a flush of the Object Cache deleting this object as it's referenceCount is now zero. Using osgDB::readREf*File() makes sure the a ref_ptr<> is
passed back and the referenceCount never goes to zero.
To ensure the OSG builds when OSG_PROVIDE_READFILE is to OFF the many cases of osgDB::read*File() usage had to be replaced with a ref_ptr<> osgDB::readRef*File()
usage. The avoid this change causing lots of other client code to be rewritten to handle the use of ref_ptr<> in place of C pointer I introduced a serious of
templte methods in various class to adapt ref_ptr<> to the underly C pointer to be passed to old OSG API's, example of this is found in include/osg/Group:
bool addChild(Node* child); // old method which can only be used with a Node*
tempalte<class T> bool addChild(const osg::ref_ptr<T>& child) { return addChild(child.get()); } // adapter template method
These changes together cover 149 modified files, so it's a large submission. This extent of changes are warrent to make use of the Object Cache
and multi-threaded loaded more robust.
git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@15164 16af8721-9629-0410-8352-f15c8da7e697
This version adds:
- an encapsulation of the entire Depth Peeling procedure into a class (not currently a scene graph node) for easier integration in other projects.
- compositing with opaque (solid) geometry is possible and the opaque model is only rendered once. This needs to performs some depth buffer blitting between FBOs.
- mix and match with GLSL shaders in the transparent objects is possible, as demonstrated with a 3D heat map intersecting an opaque truck model.
Some Drawbacks:
- the display framebuffer does not receive any depth information from the compositing camera. This could be fixed by compositing with a GLSL shader and writing to FragDepth."
From Robert Osfield, ported the code to work under Linux and without the automatic ref_ptr to C* conversion.
short oit. This rendering technique is also known as depth peeling.
Attached is the example that makes depth peeling work with the fixed function
pipeline. Ok, this is 'old fashioned' but required for our use case that
still has to work on older UNIX OpenGL implementations as well as together
with a whole existing application making use of the fixed function pipeline.
I can imagine to add support for shaders when we have that shader composition
framework where we can add a second depth test in a generic way.
This does *not* implement the dual depth peeling described in a paper from the
ETH Zurich.
This example could serve as a test case for the feature that you can on the
fly remove pre render cameras that you made work a few time ago.
It is also a test case for the new TraversalOrderBin that is used to composite
the depth layers in the correct blend order.
This example also stresses your new texture object cache since you can change
some parameters for the oit implementation at runtime.
You can just load any model with osgoit and see how it works.
Use the usual help key to see what you can change.
There is already an osgdepthpeeling example that I could not really make sense
of up to now. So I just made something new without touching what I do not
understand."
