I tried the demo in the project, and the correct aspect ratio cannot be displayed.

[fafa1899]

Hello there!
This project is great because it is implemented from QOpenGLWidget integration. When I tried its own example, osgviewerQt, I found that there was a problem with the aspect ratio of the example. By adding a line of code:
widget.resize (200, 600);
The aspect ratio displayed is even more strange, it seems that this example does not set the correct viewport or crop.
How can I adjust the code to display the correct aspect ratio?
       
Best regards

osgQt: master version
osg: 3.6.4
env: Windows 10 with vs 2017

[mathieu]

Hi @fafa1899 do you happen to have any screenshots?

[fafa1899]

Hi @mathieu

At first, after building osgQt through CMake and compiling VS2017, I directly run it in CMD through the compiled osgviewerQt program:

osgviewerQt.exe simple.earth

The rendered earth is slightly deformed:

So, to verify this problem, I added the following line of code to the end of osgviewerQt:

widget.resize(200, 600);
widget.show();

return app.exec();

"Widget.resize (200, 600);" is the code I added. This time I directly display the cow.osg that comes with OSG:

Looks like there is a problem with the aspect ratio, or should the code be adjusted to get normal results?

Thanks Reply.

[gramnation]

Same here. The demo shows correct proportions when it calls widget.show(), but adding the same widget through QMainWindow::setCentralWidget and then calling mainwindow.show() over-stretches the cow horizontally on my system (Qt5 v5.9.7).

Calling QWidget::setFixedSize before ::show() can hide this issue. Not suggesting it's a fix.

[gramnation]

See #42

[HorrZzz]

Should this issue be closed? @fafa1899 @mathieu

[fafa1899]

Should this issue be closed? @fafa1899 @mathieu

yes.
The correct answer is to set the correct aspect ratio when setting up the perspective projection, for example:

#include <QApplication>
#include <QSurfaceFormat>
#include <iostream>
#include <osgDB/ReadFile>
#include <osgGA/AnimationPathManipulator>
#include <osgGA/StateSetManipulator>
#include <osgGA/TrackballManipulator>
#include <osgQOpenGL/osgQOpenGLWidget>
#include <osgUtil/Optimizer>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>

int main(int argc, char* argv[]) {
  QSurfaceFormat format = QSurfaceFormat::defaultFormat();

#ifdef OSG_GL3_AVAILABLE
  format.setVersion(3, 2);
  format.setProfile(QSurfaceFormat::CoreProfile);
  format.setRenderableType(QSurfaceFormat::OpenGL);
  format.setOption(QSurfaceFormat::DebugContext);
#else
  format.setVersion(2, 0);
  format.setProfile(QSurfaceFormat::CompatibilityProfile);
  format.setRenderableType(QSurfaceFormat::OpenGL);
  format.setOption(QSurfaceFormat::DebugContext);
#endif
  format.setDepthBufferSize(24);
  // format.setAlphaBufferSize(8);
  format.setSamples(8);
  format.setStencilBufferSize(8);
  format.setSwapBehavior(QSurfaceFormat::DoubleBuffer);
  QSurfaceFormat::setDefaultFormat(format);

  QApplication app(argc, argv);

  osgQOpenGLWidget widget;

  QObject::connect(&widget, &osgQOpenGLWidget::initialized, [&widget] {
    // set up the camera manipulators.
    widget.getOsgViewer()->setCameraManipulator(
        new osgGA::TrackballManipulator());

    // add the state manipulator
    widget.getOsgViewer()->addEventHandler(new osgGA::StateSetManipulator(
        widget.getOsgViewer()->getCamera()->getOrCreateStateSet()));

    // add the thread model handler
    widget.getOsgViewer()->addEventHandler(new osgViewer::ThreadingHandler);

    // add the window size toggle handler
    widget.getOsgViewer()->addEventHandler(new osgViewer::WindowSizeHandler);

    // add the stats handler
    widget.getOsgViewer()->addEventHandler(new osgViewer::StatsHandler);

    // add the record camera path handler
    widget.getOsgViewer()->addEventHandler(
        new osgViewer::RecordCameraPathHandler);

    // add the LOD Scale handler
    widget.getOsgViewer()->addEventHandler(new osgViewer::LODScaleHandler);

    // add the screen capture handler
    widget.getOsgViewer()->addEventHandler(new osgViewer::ScreenCaptureHandler);

    // load the data
    std::string filename = "C:/Data/001/010137001.obj";
    osg::ref_ptr<osg::Node> loadedModel = osgDB::readRefNodeFile(filename);

    // optimize the scene graph, remove redundant nodes and state etc.
    osgUtil::Optimizer optimizer;
    optimizer.optimize(loadedModel);

    widget.getOsgViewer()->setSceneData(loadedModel);

    //Increase aspect ratio setting
    QSize size = widget.size();    
    float aspectRatio =
        static_cast<float>(size.width()) / static_cast<float>(size.height());
    widget.getOsgViewer()->getCamera()->setProjectionMatrixAsPerspective(
        60.f, aspectRatio, 1.f, 1000.f);

    return 0;
  });

  widget.resize(200, 600);
  widget.show();

  return app.exec();
}

[HorrZzz]

Should this issue be closed? @fafa1899 @mathieu

yes. The correct answer is to set the correct aspect ratio when setting up the perspective projection, for example:

#include <QApplication>
#include <QSurfaceFormat>
#include <iostream>
#include <osgDB/ReadFile>
#include <osgGA/AnimationPathManipulator>
#include <osgGA/StateSetManipulator>
#include <osgGA/TrackballManipulator>
#include <osgQOpenGL/osgQOpenGLWidget>
#include <osgUtil/Optimizer>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>

int main(int argc, char* argv[]) {
  QSurfaceFormat format = QSurfaceFormat::defaultFormat();

#ifdef OSG_GL3_AVAILABLE
  format.setVersion(3, 2);
  format.setProfile(QSurfaceFormat::CoreProfile);
  format.setRenderableType(QSurfaceFormat::OpenGL);
  format.setOption(QSurfaceFormat::DebugContext);
#else
  format.setVersion(2, 0);
  format.setProfile(QSurfaceFormat::CompatibilityProfile);
  format.setRenderableType(QSurfaceFormat::OpenGL);
  format.setOption(QSurfaceFormat::DebugContext);
#endif
  format.setDepthBufferSize(24);
  // format.setAlphaBufferSize(8);
  format.setSamples(8);
  format.setStencilBufferSize(8);
  format.setSwapBehavior(QSurfaceFormat::DoubleBuffer);
  QSurfaceFormat::setDefaultFormat(format);

  QApplication app(argc, argv);

  osgQOpenGLWidget widget;

  QObject::connect(&widget, &osgQOpenGLWidget::initialized, [&widget] {
    // set up the camera manipulators.
    widget.getOsgViewer()->setCameraManipulator(
        new osgGA::TrackballManipulator());

    // add the state manipulator
    widget.getOsgViewer()->addEventHandler(new osgGA::StateSetManipulator(
        widget.getOsgViewer()->getCamera()->getOrCreateStateSet()));

    // add the thread model handler
    widget.getOsgViewer()->addEventHandler(new osgViewer::ThreadingHandler);

    // add the window size toggle handler
    widget.getOsgViewer()->addEventHandler(new osgViewer::WindowSizeHandler);

    // add the stats handler
    widget.getOsgViewer()->addEventHandler(new osgViewer::StatsHandler);

    // add the record camera path handler
    widget.getOsgViewer()->addEventHandler(
        new osgViewer::RecordCameraPathHandler);

    // add the LOD Scale handler
    widget.getOsgViewer()->addEventHandler(new osgViewer::LODScaleHandler);

    // add the screen capture handler
    widget.getOsgViewer()->addEventHandler(new osgViewer::ScreenCaptureHandler);

    // load the data
    std::string filename = "C:/Data/001/010137001.obj";
    osg::ref_ptr<osg::Node> loadedModel = osgDB::readRefNodeFile(filename);

    // optimize the scene graph, remove redundant nodes and state etc.
    osgUtil::Optimizer optimizer;
    optimizer.optimize(loadedModel);

    widget.getOsgViewer()->setSceneData(loadedModel);

    //Increase aspect ratio setting
    QSize size = widget.size();    
    float aspectRatio =
        static_cast<float>(size.width()) / static_cast<float>(size.height());
    widget.getOsgViewer()->getCamera()->setProjectionMatrixAsPerspective(
        60.f, aspectRatio, 1.f, 1000.f);

    return 0;
  });

  widget.resize(200, 600);
  widget.show();

  return app.exec();
}

Thank you very much @fafa1899