OpenSceneGraph/examples/osgwindows/osgwindows.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

109 lines
4.0 KiB
C++

/* OpenSceneGraph example, osgwindows.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <osgDB/ReadFile>
#include <osgUtil/Optimizer>
#include <osgViewer/Viewer>
#include <iostream>
int main( int argc, char **argv )
{
// use an ArgumentParser object to manage the program arguments.
osg::ArgumentParser arguments(&argc,argv);
// read the scene from the list of file specified commandline args.
osg::ref_ptr<osg::Node> loadedModel = osgDB::readRefNodeFiles(arguments);
// if not loaded assume no arguments passed in, try use default mode instead.
if (!loadedModel) loadedModel = osgDB::readRefNodeFile("cow.osgt");
// if no model has been successfully loaded report failure.
if (!loadedModel)
{
std::cout << arguments.getApplicationName() <<": No data loaded" << std::endl;
return 1;
}
// construct the viewer.
osgViewer::Viewer viewer;
int xoffset = 40;
int yoffset = 40;
// left window + left slave camera
{
osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;
traits->x = xoffset + 0;
traits->y = yoffset + 0;
traits->width = 600;
traits->height = 480;
traits->windowDecoration = true;
traits->doubleBuffer = true;
traits->sharedContext = 0;
osg::ref_ptr<osg::GraphicsContext> gc = osg::GraphicsContext::createGraphicsContext(traits.get());
osg::ref_ptr<osg::Camera> camera = new osg::Camera;
camera->setGraphicsContext(gc.get());
camera->setViewport(new osg::Viewport(0,0, traits->width, traits->height));
GLenum buffer = traits->doubleBuffer ? GL_BACK : GL_FRONT;
camera->setDrawBuffer(buffer);
camera->setReadBuffer(buffer);
// add this slave camera to the viewer, with a shift left of the projection matrix
viewer.addSlave(camera.get(), osg::Matrixd::translate(1.0,0.0,0.0), osg::Matrixd());
}
// right window + right slave camera
{
osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;
traits->x = xoffset + 600;
traits->y = yoffset + 0;
traits->width = 600;
traits->height = 480;
traits->windowDecoration = true;
traits->doubleBuffer = true;
traits->sharedContext = 0;
osg::ref_ptr<osg::GraphicsContext> gc = osg::GraphicsContext::createGraphicsContext(traits.get());
osg::ref_ptr<osg::Camera> camera = new osg::Camera;
camera->setGraphicsContext(gc.get());
camera->setViewport(new osg::Viewport(0,0, traits->width, traits->height));
GLenum buffer = traits->doubleBuffer ? GL_BACK : GL_FRONT;
camera->setDrawBuffer(buffer);
camera->setReadBuffer(buffer);
// add this slave camera to the viewer, with a shift right of the projection matrix
viewer.addSlave(camera.get(), osg::Matrixd::translate(-1.0,0.0,0.0), osg::Matrixd());
}
// optimize the scene graph, remove redundant nodes and state etc.
osgUtil::Optimizer optimizer;
optimizer.optimize(loadedModel);
// set the scene to render
viewer.setSceneData(loadedModel);
return viewer.run();
}