History: QtOgre

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            Note: There is a recent QOgreWidget written by djbe that is tested on Mac and Linux: [http://www.ogre3d.org/phpBB2/viewtopic.php?p=258064] ((User:Alanic|Alanic))

I found this documentation: [http://lakin.weckers.net/index_ogre.html|Lakin's Ogre-Qt].

It is for Linux.. I prefer to do my development on my Windows machine (it has more ram / better video) and when I develop on Windows I use Visual Studio. As such, [http://www.qtnode.net/wiki/Qt4_with_Visual_Studio|these instructions] are priceless.

Once you have Qt built and you've set up your environment variables, you can run qmake on Ogre-Qt to get a vcproj. Open that up in visual studio and the first thing you'll have to do is add the OGRE include directory to the C++ Additional Include Directories. If you try to build now you will see some errors like this:

{CODE(wrap="1", colors="dos")}1>c:\qt-4.2.3-msvc2005\include\qtcore\../../src/corelib/tools/qhash.h(175) : error C2872: 'uint' : ambiguous symbol
1>        could be 'c:\qt-4.2.3-msvc2005\include\qtcore\../../src/corelib/global/qglobal.h(632) : unsigned int uint'
1>        or 'c:\ogresdk\include\OgrePrerequisites.h(134) : Ogre::uint'{CODE}

There's a whole bunch of these, you need to add :: to the front of any reference to uint in the Qt code. You shouldn't need to recompile Qt after you do this.

Then you need to add the OGRE lib directory to the Linker Additional Library Directories and add OgreMain.lib to Linker Inputs.

For the debug configuration you will want to do the same but use OgreMain_d.lib.

Of course, so far my success rate hasn't been too high.

!!An Example using QT4 and Ogre Eihort
This is a standard QT Widget with an Ogre instance in it. You can create one on QT's designer by elevating a regular widget to an "OgreWidget" and including ogrewidget.h in your project. You'll probably want to do something about the chooseRenderer() function, since it doesn't really do much right now. I generally derive another class from this one and reimplement chooseRenderer(), and build my world in that class. Good Luck with it!

!!!ogrewidget.h:
{CODE(wrap="1", colors="cpp-qt")}#ifndef __OGREWIDGET_H__
#define __OGREWIDGET_H__

#include <OGRE/Ogre.h>
#include <QGLWidget>
#include <QX11Info>

class OgreWidget : public QGLWidget
{
  //Q_OBJECT;
  
 public:
  OgreWidget( QWidget *parent=0 ):
    QGLWidget( parent ),
    mOgreWindow(NULL)
    {
      init( "../bin/plugins.cfg", "../bin/ogre.cfg", "../bin/ogre.log" );
    }
  
  virtual ~OgreWidget()
    {
      mOgreRoot->shutdown();
      delete mOgreRoot;
      destroy();
    }
  
 protected:
  virtual void initializeGL();
  virtual void resizeGL( int, int );
  virtual void paintGL();

  void init( std::string, std::string, std::string );

  virtual Ogre::RenderSystem* chooseRenderer( Ogre::RenderSystemList* );

  Ogre::Root *mOgreRoot;
  Ogre::RenderWindow *mOgreWindow;
  Ogre::Camera *mCamera;
  Ogre::Viewport *mViewport;
  Ogre::SceneManager *mSceneMgr;
};

#endif{CODE}

!!!ogrewidget.cpp:
{CODE(wrap="1", colors="cpp-qt")}#include "ogrewidget.h"

#define THIS OgreWidget

/**
 * @brief init the object
 * @author kito berg-taylor
 */
void THIS::init( std::string plugins_file,
         std::string ogre_cfg_file,
         std::string ogre_log )
{
  // create the main ogre object
  mOgreRoot = new Ogre::Root( plugins_file, ogre_cfg_file, ogre_log );

  // setup a renderer
  Ogre::RenderSystemList *renderers = mOgreRoot->getAvailableRenderers();
  assert( !renderers->empty() ); // we need at least one renderer to do anything useful

  Ogre::RenderSystem *renderSystem;
  renderSystem = chooseRenderer( renderers );

  assert( renderSystem ); // user might pass back a null renderer, which would be bad!

  mOgreRoot->setRenderSystem( renderSystem );
  QString dimensions = QString( "%1x%2" )
                    .arg(this->width())
                    .arg(this->height());

  renderSystem->setConfigOption( "Video Mode", dimensions.toStdString() );

  // initialize without creating window
  mOgreRoot->getRenderSystem()->setConfigOption( "Full Screen", "No" );
  mOgreRoot->saveConfig();
  mOgreRoot->initialise(false); // don't create a window
}

/**
 * @brief setup the rendering context
 * @author Kito Berg-Taylor
 */
void THIS::initializeGL()
{
  //== Creating and Acquiring Ogre Window ==//

  // Get the parameters of the window QT created
  Ogre::String winHandle;
  #ifdef WIN32
  // Windows code
  winHandle += Ogre::StringConverter::toString((unsigned long)(this->parentWidget()->winId()));
  #else
  // Unix code
  QX11Info info = x11Info();
  winHandle  = Ogre::StringConverter::toString((unsigned long)(info.display()));
  winHandle += ":";
  winHandle += Ogre::StringConverter::toString((unsigned int)(info.screen()));
  winHandle += ":";
  winHandle += Ogre::StringConverter::toString((unsigned long)(this->parentWidget()->winId()));
  #endif
  
  Ogre::NameValuePairList params;
  params["parentWindowHandle"] = winHandle;

  mOgreWindow = mOgreRoot->createRenderWindow( "QOgreWidget_RenderWindow",
                           this->width(),
                           this->height(),
                           false,
                           &params );

  mOgreWindow->setActive(true);
  WId ogreWinId = 0x0;
  mOgreWindow->getCustomAttribute( "WINDOW", &ogreWinId );
  
  assert( ogreWinId );

  this->create( ogreWinId );
  setAttribute( Qt::WA_PaintOnScreen, true );
  setAttribute( Qt::WA_NoBackground );

  //== Ogre Initialization ==//
  Ogre::SceneType scene_manager_type = Ogre::ST_EXTERIOR_CLOSE;

  mSceneMgr = mOgreRoot->createSceneManager( scene_manager_type );
  mSceneMgr->setAmbientLight( Ogre::ColourValue(1,1,1) );

  mCamera = mSceneMgr->createCamera( "QOgreWidget_Cam" );
  mCamera->setPosition( Ogre::Vector3(0,1,0) );
  mCamera->lookAt( Ogre::Vector3(0,0,0) );
  mCamera->setNearClipDistance( 1.0 );

  Ogre::Viewport *mViewport = mOgreWindow->addViewport( mCamera );
  mViewport->setBackgroundColour( Ogre::ColourValue( 0.8,0.8,1 ) );
}

/**
 * @brief render a frame
 * @author Kito Berg-Taylor
 */
void THIS::paintGL()
{
  assert( mOgreWindow );
  mOgreRoot->renderOneFrame();
}

/**
 * @brief resize the GL window
 * @author Kito Berg-Taylor
 */
void THIS::resizeGL( int width, int height )
{
  assert( mOgreWindow );
  mOgreWindow->windowMovedOrResized();
}

/**
 * @brief choose the right renderer
 * @author Kito Berg-Taylor
 */
Ogre::RenderSystem* THIS::chooseRenderer( Ogre::RenderSystemList *renderers )
{
  // It would probably be wise to do something more friendly 
  // that just use the first available renderer
  return *renderers->begin();
}{CODE}