OpenSceneGraph/examples/osgoutline/osgoutline.cpp
Robert Osfield 6a67be2e32 Introduced CMake option OSG_PROVIDE_READFILE option that defaults to ON, but when switched to OFF disables the building of the osgDB::read*File() methods,
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/branches/OpenSceneGraph-3.4@15165 16af8721-9629-0410-8352-f15c8da7e697
2015-10-22 14:14:53 +00:00

90 lines
3.0 KiB
C++

// -*-c++-*-
/*
* Draw an outline around a model.
*/
#include <osg/Group>
#include <osg/PositionAttitudeTransform>
#include <osgDB/ReadFile>
#include <osgViewer/Viewer>
#include <osgFX/Outline>
int main(int argc, char** argv)
{
osg::ArgumentParser arguments(&argc,argv);
arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName()+" [options] <file>");
arguments.getApplicationUsage()->addCommandLineOption("--testOcclusion","Test occlusion by other objects");
arguments.getApplicationUsage()->addCommandLineOption("-h or --help","Display this information");
bool testOcclusion = false;
while (arguments.read("--testOcclusion")) { testOcclusion = true; }
// load outlined object
std::string modelFilename = arguments.argc() > 1 ? arguments[1] : "dumptruck.osgt";
osg::ref_ptr<osg::Node> outlineModel = osgDB::readRefNodeFile(modelFilename);
if (!outlineModel)
{
osg::notify(osg::FATAL) << "Unable to load model '" << modelFilename << "'\n";
return -1;
}
// create scene
osg::ref_ptr<osg::Group> root = new osg::Group;
{
// create outline effect
osg::ref_ptr<osgFX::Outline> outline = new osgFX::Outline;
root->addChild(outline);
outline->setWidth(8);
outline->setColor(osg::Vec4(1,1,0,1));
outline->addChild(outlineModel);
}
if (testOcclusion)
{
// load occluder
std::string occludedModelFilename = "cow.osgt";
osg::ref_ptr<osg::Node> occludedModel = osgDB::readRefNodeFile(occludedModelFilename);
if (!occludedModel)
{
osg::notify(osg::FATAL) << "Unable to load model '" << occludedModelFilename << "'\n";
return -1;
}
// occluder offset
const osg::BoundingSphere& bsphere = outlineModel->getBound();
const osg::Vec3 occluderOffset = osg::Vec3(0,1,0) * bsphere.radius() * 1.2f;
// occluder behind outlined model
osg::ref_ptr<osg::PositionAttitudeTransform> modelTransform0 = new osg::PositionAttitudeTransform;
modelTransform0->setPosition(bsphere.center() + occluderOffset);
modelTransform0->addChild(occludedModel);
root->addChild(modelTransform0);
// occluder in front of outlined model
osg::ref_ptr<osg::PositionAttitudeTransform> modelTransform1 = new osg::PositionAttitudeTransform;
modelTransform1->setPosition(bsphere.center() - occluderOffset);
modelTransform1->addChild(occludedModel);
root->addChild(modelTransform1);
}
// must have stencil buffer...
osg::DisplaySettings::instance()->setMinimumNumStencilBits(1);
// construct the viewer
osgViewer::Viewer viewer;
viewer.setSceneData(root);
// must clear stencil buffer...
unsigned int clearMask = viewer.getCamera()->getClearMask();
viewer.getCamera()->setClearMask(clearMask | GL_STENCIL_BUFFER_BIT);
viewer.getCamera()->setClearStencil(0);
return viewer.run();
}