Hello everyone,
I am trying to use OSG 3.0.1 with Qt 4.8.0, with the mingw 64-bit compiler on
Win7 Pro.
So far, I have successfully set up a 64-bit build environment (in C:\mingw64)
and built the Qt libraries. All the Qt examples work, and I’m able to create
new Qt programs quickly and easily.
Next, I downloaded OSG 3.0.1 and built it, using CMake. The osgviewerQt example
program compiled and ran fine, so I thought I was ready to start writing
programs that use OSG and Qt together. This is when the strangeness started.
As a first test, I tried reproducing the osgviewerQt example program myself
using Qt Creator. I created a new Qt Widget app, and copy & pasted code from
the osgviewerQt example. After setting up the .pro file, to link with the
required OSG DLL files, the application built without any errors. However, it
did not run.
I ran my test program in a debugger, and here is the backtrace:
First chance exception 0x00000000C0000005 ACCESS_VIOLATION occurred at
0x0000000000782803, read of address 0xFFFFFFFFFFFFFFFF at 0x0000000000782803
(in C:\Users\Markus\Desktop\OSG examples\libosgd.dll)
0x0000000000782803 _ZN3osg6Object21setThreadSafeRefUnrefEb + 0x4B in libosgd.dll
0x000000006AE05B7F _ZN9osgViewer15CompositeViewer15constructorInitEv + 0x117 in
libosgViewerd.dll
0x000000006AE015D1 _ZN9osgViewer15CompositeViewerC2Ev + 0x191 in
libosgViewerd.dll
0x0000000000401BB8 OsgQtTest02.exe
0x0000000000401615 OsgQtTest02.exe
0x00000000004013CE OsgQtTest02.exe
0x00000000004014E8 OsgQtTest02.exe
0x000000007675652D BaseThreadInitThunk + 0xD in kernel32.dll
0x0000000076CEC521 RtlUserThreadStart + 0x21 in ntdll.dll
(My test program is called OsgQtTest02.exe)
I can reproduce this behaviour easily, just by deriving a class from QWidget
and osgViewer::CompositeViewer, and then creating an instance of it in
main.cpp, like this:
#include < QtGui/QApplication >
#include "viewwidget.h"
#include < iostream >
int main(int argc, char *argv[])
{
std::cout << "Program starting" << std::endl;
QApplication a(argc, argv);
ViewWidget w;
std::cout << "Widget created" << std::endl;
w.show();
return a.exec();
}
This is the declaration of the ViewWidget class:
#include < QtGui/QWidget >
#include < osgViewer/CompositeViewer >
class ViewWidget : public QWidget, public osgViewer::CompositeViewer
{
//Q_OBJECT
public:
ViewWidget(QWidget *parent = 0);
~ViewWidget();
};
The message "Program starting" will appear, but "Widget created" will not,
because the app will crash when the ViewWidget instance is created. The
presence of Q_OBJECT seems to make no difference.
This has the feeling of a C++ ABI incompatibility, as if the C++ OSG DLLs were
built with a different C++ compiler. However I know that this is not the case,
because I built everything myself, with the same C++ compiler (except Qt
Creator itself of course).
I have tried rebuilding Qt and OSG a few times over the weekend, and I have
been over the CMake setup until the wee hours at night. I don’t seem to be
missing anything obvious. With Dependency Walker, I can verify that my app is
properly linked to the OSG and Qt DLLs.
I am at my wits’ end...
Does anybody have any advice on how to fix this problem?
Many thanks in advance,
Markus Svilans
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http://forum.openscenegraph.org/viewtopic.php?p=47084#47084
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