Integrating Ogre into QT5        

Introduction

Original forum link: http://www.ogre3d.org/forums/viewtopic.php?p=515314#p515314

The following document is an up-to-date method of integrating Ogre3D into the latest version of Qt (5.4 as of this writing).

Previous methods of integrating Ogre3D with Qt focused on using a QWidget and overriding the paint methods for drawing.

The method proposed in this document uses a QWindow as opposed to a QWidget. There are several reasons for using a QWindow over a QWidget, outlined in the next section.

Reasons for using QWindow over QWidget

  • Smaller memory and processing footprint. Simply put, QWidgets use a lot of resources in comparison to QWindows and thus adds a lot of unnecessary overhead. Ogre3D doesn't require much from Qt besides a surface to draw upon and the input/window events from the underlying OS and windowing system that a QWindow provides. As a related sidenote, QWidget actually inherits from QWindow as shown in the below inheritance chain.
  • Easier integration. Because of the simplicity of QWindow it is actually much easier to integrate Ogre3D into Qt using a QWindow versus using a QWidget. QWidget by default creates a surface to draw on which Ogre3D doesn't need to draw upon. Thus, as shown in earlier Qt-Ogre3D implementation documents you need to override Qt methods to prevent the default QWidget methods from "drawing over" Ogre3D. Using a QWindow this is unnecessary as with a QWindow no "surface" is automatically created; you can simply supply QWindow's native "Window ID" (whether it is a HWND on Windows or the equivalent representations on Linux/Mac OS) and Ogre3D takes care of the rest.
  • All standard Qt functionality can still be implemented. If you still need to have a QWidget (for integration into a QMainWindow/QTabWidget/etc.) this can still be achieved. You can easily create a QWidget "container" for your QWindow and get all of the standard benefits of a QWidget. A standard use case for this would be needing to place an Ogre3D-integrated QWindow inside of a standard QMainWindow as a "central widget".

Inheritance Chain of QWidget


Example integration code

Note that the below implementation depends on you following the guides on setting up include/library/runtime binary directories. Since the setup for this is compiler and operating system dependent such details is beyond the scope of this document.

In summary, consult a guide like this for setting up directory paths, includes, etc. Note that you will need to do this for Qt as well so consult equivalent documentation for Qt Creator like this.

With the proper setup of the environment done, we need to create a header file to include the necessary Qt components as well as including Ogre3D:

#ifndef QTOGREWINDOW_H
#define QTOGREWINDOW_H

/*
Qt headers
*/
#include <QtWidgets/QApplication>
#include <QtGui/QKeyEvent>
#include <QtGui/QWindow>

/*
Ogre3D header
*/
#include <Ogre.h>

/*
Changed SdkCameraMan implementation to work with QKeyEvent, QMouseEvent, QWheelEvent
*/
#include "SdkQtCameraMan.h"

/*
With the headers included we now need to inherit from QWindow.
*/
class QTOgreWindow : public QWindow, public Ogre::FrameListener
{
	/*
	A QWindow still inherits from QObject and can have signals/slots; we need to add the appropriate
	Q_OBJECT keyword so that Qt's intermediate compiler can do the necessary wireup between our class
	and the rest of Qt.
	*/
	Q_OBJECT

public:
	explicit QTOgreWindow(QWindow *parent = NULL);
	~QTOgreWindow();

	/*
	We declare these methods virtual to allow for further inheritance.
	*/
	virtual void render(QPainter *painter);
	virtual void render();
	virtual void initialize();
	virtual void createScene();
#if OGRE_VERSION >= ((2 << 16) | (0 << 8) | 0)
	virtual void createCompositor();
#endif

	void setAnimating(bool animating);

public slots:

	virtual void renderLater();
	virtual void renderNow();

	/*
	We use an event filter to be able to capture keyboard/mouse events. More on this later.
	*/
	virtual bool eventFilter(QObject *target, QEvent *event);

signals:
	/*
	Event for clicking on an entity.
	*/
	void entitySelected(Ogre::Entity* entity);

protected:
	/*
	Ogre3D pointers added here. Useful to have the pointers here for use by the window later.
	*/
	Ogre::Root* m_ogreRoot;
	Ogre::RenderWindow* m_ogreWindow;
	Ogre::SceneManager* m_ogreSceneMgr;
	Ogre::Camera* m_ogreCamera;
	Ogre::ColourValue m_ogreBackground;
	OgreQtBites::SdkQtCameraMan* m_cameraMan;

	bool m_update_pending;
	bool m_animating;

	/*
	The below methods are what is actually fired when they keys on the keyboard are hit.
	Similar events are fired when the mouse is pressed or other events occur.
	*/
	virtual void keyPressEvent(QKeyEvent * ev);
	virtual void keyReleaseEvent(QKeyEvent * ev);
	virtual void mouseMoveEvent(QMouseEvent* e);
	virtual void wheelEvent(QWheelEvent* e);
	virtual void mousePressEvent(QMouseEvent* e);
	virtual void mouseReleaseEvent(QMouseEvent* e);
	virtual void exposeEvent(QExposeEvent *event);
	virtual bool event(QEvent *event);

	/*
	FrameListener method
	*/
	virtual bool frameRenderingQueued(const Ogre::FrameEvent& evt);

	/*
	Write log messages to Ogre log
	*/
	void log(Ogre::String msg);
	void log(QString msg);
};

#endif // QTOGREWINDOW_H


With the header prepared, it's now time to implement the class:

#include "QTOgreWindow.h"
#if OGRE_VERSION >= ((2 << 16) | (0 << 8) | 0)
#include <Compositor/OgreCompositorManager2.h>
#endif

/*
Note that we pass any supplied QWindow parent to the base QWindow class. This is necessary should we
need to use our class within a container.
*/
QTOgreWindow::QTOgreWindow(QWindow *parent)
	: QWindow(parent)
	, m_update_pending(false)
	, m_animating(false)
	, m_ogreRoot(NULL)
	, m_ogreWindow(NULL)
	, m_ogreCamera(NULL)
	, m_cameraMan(NULL)
{
	setAnimating(true);
	installEventFilter(this);
	m_ogreBackground = Ogre::ColourValue(0.0f, 0.5f, 1.0f);
}

/*
Upon destruction of the QWindow object we destroy the Ogre3D scene.
*/
QTOgreWindow::~QTOgreWindow()
{
	if (m_cameraMan) delete m_cameraMan;
	delete m_ogreRoot;
}

/*
In case any drawing surface backing stores (QRasterWindow or QOpenGLWindow) of Qt are supplied to this
class in any way we inform Qt that they will be unused.
*/
void QTOgreWindow::render(QPainter *painter)
{
	Q_UNUSED(painter);
}

/*
Our initialization function. Called by our renderNow() function once when the window is first exposed.
*/
void QTOgreWindow::initialize()
{
	/*
	As shown Ogre3D is initialized normally; just like in other documentation.
	*/
#ifdef _MSC_VER
	m_ogreRoot = new Ogre::Root(Ogre::String("plugins" OGRE_BUILD_SUFFIX ".cfg"));
#else
	m_ogreRoot = new Ogre::Root(Ogre::String("plugins.cfg"));
#endif
	Ogre::ConfigFile ogreConfig;

	/*

	Commended out for simplicity but should you need to initialize resources you can do so normally.

	ogreConfig.load("resources/resource_configs/resources.cfg");

	Ogre::ConfigFile::SectionIterator seci = ogreConfig.getSectionIterator();
	Ogre::String secName, typeName, archName;
	while (seci.hasMoreElements())
	{
		secName = seci.peekNextKey();
		Ogre::ConfigFile::SettingsMultiMap *settings = seci.getNext();
		Ogre::ConfigFile::SettingsMultiMap::iterator i;
		for (i = settings->begin(); i != settings->end(); ++i)
		{
			typeName = i->first;
			archName = i->second;
			Ogre::ResourceGroupManager::getSingleton().addResourceLocation(
			archName, typeName, secName);
		}
	}

	*/

	const Ogre::RenderSystemList& rsList = m_ogreRoot->getAvailableRenderers();
	Ogre::RenderSystem* rs = rsList[0];

	/*
	This list setup the search order for used render system.
	*/
	Ogre::StringVector renderOrder;
#if defined(Q_OS_WIN)
	renderOrder.push_back("Direct3D9");
	renderOrder.push_back("Direct3D11");
#endif
	renderOrder.push_back("OpenGL");
	renderOrder.push_back("OpenGL 3+");
	for (Ogre::StringVector::iterator iter = renderOrder.begin(); iter != renderOrder.end(); iter++)
	{
		for (Ogre::RenderSystemList::const_iterator it = rsList.begin(); it != rsList.end(); it++)
		{
			if ((*it)->getName().find(*iter) != Ogre::String::npos)
			{
				rs = *it;
				break;
			}
		}
		if (rs != NULL) break;
	}
	if (rs == NULL)
	{
		if (!m_ogreRoot->restoreConfig())
		{
			if (!m_ogreRoot->showConfigDialog())
				OGRE_EXCEPT(Ogre::Exception::ERR_INVALIDPARAMS,
					"Abort render system configuration",
					"QTOgreWindow::initialize");
		}
	}

	/*
	Setting size and VSync on windows will solve a lot of problems
	*/
	QString dimensions = QString("%1 x %2").arg(this->width()).arg(this->height());
	rs->setConfigOption("Video Mode", dimensions.toStdString());
	rs->setConfigOption("Full Screen", "No");
	rs->setConfigOption("VSync", "Yes");
	m_ogreRoot->setRenderSystem(rs);
	m_ogreRoot->initialise(false);

	Ogre::NameValuePairList parameters;
	/*
	Flag within the parameters set so that Ogre3D initializes an OpenGL context on it's own.
	*/
	if (rs->getName().find("GL") <= rs->getName().size())
		parameters["currentGLContext"] = Ogre::String("false");

	/*
	We need to supply the low level OS window handle to this QWindow so that Ogre3D knows where to draw
	the scene. Below is a cross-platform method on how to do this.
	If you set both options (externalWindowHandle and parentWindowHandle) this code will work with OpenGL
	and DirectX.
	*/
#if defined(Q_OS_MAC) || defined(Q_OS_WIN)
	parameters["externalWindowHandle"] = Ogre::StringConverter::toString((size_t)(this->winId()));
	parameters["parentWindowHandle"] = Ogre::StringConverter::toString((size_t)(this->winId()));
#else
	parameters["externalWindowHandle"] = Ogre::StringConverter::toString((unsigned long)(this->winId()));
	parameters["parentWindowHandle"] = Ogre::StringConverter::toString((unsigned long)(this->winId()));
#endif

#if defined(Q_OS_MAC)
	parameters["macAPI"] = "cocoa";
	parameters["macAPICocoaUseNSView"] = "true";
#endif

	/*
	Note below that we supply the creation function for the Ogre3D window the width and height
	from the current QWindow object using the "this" pointer.
	*/
	m_ogreWindow = m_ogreRoot->createRenderWindow("QT Window",
		this->width(),
		this->height(),
		false,
		&parameters);
	m_ogreWindow->setVisible(true);

	/*
	The rest of the code in the initialization function is standard Ogre3D scene code. Consult other
	tutorials for specifics.
	*/
#if OGRE_VERSION >= ((2 << 16) | (0 << 8) | 0)
	const size_t numThreads = std::max<int>(1, Ogre::PlatformInformation::getNumLogicalCores());
	Ogre::InstancingThreadedCullingMethod threadedCullingMethod = Ogre::INSTANCING_CULLING_SINGLETHREAD;
	if (numThreads > 1)threadedCullingMethod = Ogre::INSTANCING_CULLING_THREADED;
	m_ogreSceneMgr = m_ogreRoot->createSceneManager(Ogre::ST_GENERIC, numThreads, threadedCullingMethod);
#else
	m_ogreSceneMgr = m_ogreRoot->createSceneManager(Ogre::ST_GENERIC);
#endif
	
	m_ogreCamera = m_ogreSceneMgr->createCamera("MainCamera");
	m_ogreCamera->setPosition(Ogre::Vector3(0.0f, 0.0f, 10.0f));
	m_ogreCamera->lookAt(Ogre::Vector3(0.0f, 0.0f, -300.0f));
	m_ogreCamera->setNearClipDistance(0.1f);
	m_ogreCamera->setFarClipDistance(200.0f);
	m_cameraMan = new OgreQtBites::SdkQtCameraMan(m_ogreCamera);   // create a default camera controller

#if OGRE_VERSION >= ((2 << 16) | (0 << 8) | 0)
	createCompositor();
#else
	Ogre::Viewport* pViewPort = m_ogreWindow->addViewport(m_ogreCamera);
	pViewPort->setBackgroundColour(m_ogreBackground);
#endif

	m_ogreCamera->setAspectRatio(
		Ogre::Real(m_ogreWindow->getWidth()) / Ogre::Real(m_ogreWindow->getHeight()));
	m_ogreCamera->setAutoAspectRatio(true);

	Ogre::TextureManager::getSingleton().setDefaultNumMipmaps(5);
	Ogre::ResourceGroupManager::getSingleton().initialiseAllResourceGroups();

	createScene();

	m_ogreRoot->addFrameListener(this);
}

void QTOgreWindow::createScene()
{
	/*
	Example scene
	Derive this class for your own purpose and overwite this function to have a working Ogre widget with
	your own content.
	*/
	m_ogreSceneMgr->setAmbientLight(Ogre::ColourValue(0.5f, 0.5f, 0.5f));

#if OGRE_VERSION >= ((2 << 16) | (0 << 8) | 0)
	Ogre::Entity* sphereMesh = m_ogreSceneMgr->createEntity(Ogre::SceneManager::PT_SPHERE);
#else
	Ogre::Entity* sphereMesh = m_ogreSceneMgr->createEntity("mySphere", Ogre::SceneManager::PT_SPHERE);
#endif

	Ogre::SceneNode* childSceneNode = m_ogreSceneMgr->getRootSceneNode()->createChildSceneNode();

	childSceneNode->attachObject(sphereMesh);

	Ogre::MaterialPtr sphereMaterial = Ogre::MaterialManager::getSingleton().create("SphereMaterial",
		Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME, true);

	sphereMaterial->getTechnique(0)->getPass(0)->setAmbient(0.1f, 0.1f, 0.1f);
	sphereMaterial->getTechnique(0)->getPass(0)->setDiffuse(0.2f, 0.2f, 0.2f, 1.0f);
	sphereMaterial->getTechnique(0)->getPass(0)->setSpecular(0.9f, 0.9f, 0.9f, 1.0f);
	//sphereMaterial->setAmbient(0.2f, 0.2f, 0.5f);
	//sphereMaterial->setSelfIllumination(0.2f, 0.2f, 0.1f);

	sphereMesh->setMaterialName("SphereMaterial");
	childSceneNode->setPosition(Ogre::Vector3(0.0f, 0.0f, 0.0f));
	childSceneNode->setScale(Ogre::Vector3(0.01f, 0.01f, 0.01f)); // Radius, in theory.

#if OGRE_VERSION >= ((2 << 16) | (0 << 8) | 0)
	Ogre::SceneNode* pLightNode = m_ogreSceneMgr->getRootSceneNode()->createChildSceneNode();
	Ogre::Light* light = m_ogreSceneMgr->createLight();
	pLightNode->attachObject(light);
	pLightNode->setPosition(20.0f, 80.0f, 50.0f);
#else
	Ogre::Light* light = m_ogreSceneMgr->createLight("MainLight");
	light->setPosition(20.0f, 80.0f, 50.0f);
#endif
}

#if OGRE_VERSION >= ((2 << 16) | (0 << 8) | 0)
void QTOgreWindow::createCompositor()
{
	/*
	Example compositor
	Derive this class for your own purpose and overwite this function to have a working Ogre
	widget with your own compositor.
	*/
	Ogre::CompositorManager2* compMan = m_ogreRoot->getCompositorManager2();
	const Ogre::String workspaceName = "default scene workspace";
	const Ogre::IdString workspaceNameHash = workspaceName;
	compMan->createBasicWorkspaceDef(workspaceName, m_ogreBackground);
	compMan->addWorkspace(m_ogreSceneMgr, m_ogreWindow, m_ogreCamera, workspaceNameHash, true);
}
#endif

void QTOgreWindow::render()
{
	/*
	How we tied in the render function for OGre3D with QWindow's render function. This is what gets call
	repeatedly. Note that we don't call this function directly; rather we use the renderNow() function
	to call this method as we don't want to render the Ogre3D scene unless everything is set up first.
	That is what renderNow() does.

	Theoretically you can have one function that does this check but from my experience it seems better
	to keep things separate and keep the render function as simple as possible.
	*/
	Ogre::WindowEventUtilities::messagePump();
	m_ogreRoot->renderOneFrame();
}

void QTOgreWindow::renderLater()
{
	/*
	This function forces QWindow to keep rendering. Omitting this causes the renderNow() function to
	only get called when the window is resized, moved, etc. as opposed to all of the time; which is
	generally what we need.
	*/
	if (!m_update_pending)
	{
		m_update_pending = true;
		QApplication::postEvent(this, new QEvent(QEvent::UpdateRequest));
	}
}

bool QTOgreWindow::event(QEvent *event)
{
	/*
	QWindow's "message pump". The base method that handles all QWindow events. As you will see there
	are other methods that actually process the keyboard/other events of Qt and the underlying OS.

	Note that we call the renderNow() function which checks to see if everything is initialized, etc.
	before calling the render() function.
	*/

	switch (event->type())
	{
	case QEvent::UpdateRequest:
		m_update_pending = false;
		renderNow();
		return true;

	default:
		return QWindow::event(event);
	}
}

/*
Called after the QWindow is reopened or when the QWindow is first opened.
*/
void QTOgreWindow::exposeEvent(QExposeEvent *event)
{
	Q_UNUSED(event);

	if (isExposed())
		renderNow();
}

/*
The renderNow() function calls the initialize() function when needed and if the QWindow is already
initialized and prepped calls the render() method.
*/
void QTOgreWindow::renderNow()
{
	if (!isExposed())
		return;

	if (m_ogreRoot == NULL)
	{
		initialize();
	}

	render();

	if (m_animating)
        renderLater();
}

/*
Our event filter; handles the resizing of the QWindow. When the size of the QWindow changes note the
call to the Ogre3D window and camera. This keeps the Ogre3D scene looking correct.
*/
bool QTOgreWindow::eventFilter(QObject *target, QEvent *event)
{
	if (target == this)
	{
		if (event->type() == QEvent::Resize)
		{
			if (isExposed() && m_ogreWindow != NULL)
			{
				m_ogreWindow->resize(this->width(), this->height());
			}
		}
	}

	return false;
}

/*
How we handle keyboard and mouse events.
*/
void QTOgreWindow::keyPressEvent(QKeyEvent * ev)
{
	if(m_cameraMan)
		m_cameraMan->injectKeyDown(*ev);
}

void QTOgreWindow::keyReleaseEvent(QKeyEvent * ev)
{
	if(m_cameraMan)
		m_cameraMan->injectKeyUp(*ev);
}

void QTOgreWindow::mouseMoveEvent( QMouseEvent* e )
{
	static int lastX = e->x();
	static int lastY = e->y();
	int relX = e->x() - lastX;
	int relY = e->y() - lastY;
	lastX = e->x();
	lastY = e->y();

	if(m_cameraMan && (e->buttons() & Qt::LeftButton))
		m_cameraMan->injectMouseMove(relX, relY);
}

void QTOgreWindow::wheelEvent(QWheelEvent *e)
{
	if(m_cameraMan)
		m_cameraMan->injectWheelMove(*e);
}

void QTOgreWindow::mousePressEvent( QMouseEvent* e )
{
	if(m_cameraMan)
		m_cameraMan->injectMouseDown(*e);
}

void QTOgreWindow::mouseReleaseEvent( QMouseEvent* e )
{
	if(m_cameraMan)
		m_cameraMan->injectMouseUp(*e);

	QPoint pos = e->pos();
	Ogre::Ray mouseRay = m_ogreCamera->getCameraToViewportRay(
		(Ogre::Real)pos.x() / m_ogreWindow->getWidth(),
		(Ogre::Real)pos.y() / m_ogreWindow->getHeight());
	Ogre::RaySceneQuery* pSceneQuery = m_ogreSceneMgr->createRayQuery(mouseRay);
	pSceneQuery->setSortByDistance(true);
	Ogre::RaySceneQueryResult vResult = pSceneQuery->execute();
	for (size_t ui = 0; ui < vResult.size(); ui++)
	{
		if (vResult[ui].movable)
		{
			if (vResult[ui].movable->getMovableType().compare("Entity") == 0)
			{
				emit entitySelected((Ogre::Entity*)vResult[ui].movable);
			}
		}
	}
	m_ogreSceneMgr->destroyQuery(pSceneQuery);
}

/*
Function to keep track of when we should and shouldn't redraw the window; we wouldn't want to do
rendering when the QWindow is minimized. This takes care of those scenarios.
*/
void QTOgreWindow::setAnimating(bool animating)
{
	m_animating = animating;

	if (animating)
		renderLater();
}

bool QTOgreWindow::frameRenderingQueued(const Ogre::FrameEvent& evt)
{
	m_cameraMan->frameRenderingQueued(evt);
	return true;
}

void QTOgreWindow::log(Ogre::String msg)
{
	if(Ogre::LogManager::getSingletonPtr() != NULL) Ogre::LogManager::getSingletonPtr()->logMessage(msg);
}

void QTOgreWindow::log(QString msg)
{
	log(Ogre::String(msg.toStdString().c_str()));
}


The camera manager is a modified copy of the SDK version.

/*
 -----------------------------------------------------------------------------
 This source file is part of OGRE
 (Object-oriented Graphics Rendering Engine)
 For the latest info, see http://www.ogre3d.org/
 
 Copyright (c) 2000-2014 Torus Knot Software Ltd
 
 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 above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
 
 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.
 -----------------------------------------------------------------------------
 */
// File modified to change OIS to Qt KeyEvents
#ifndef __SdkQtCameraMan_H__
#define __SdkQtCameraMan_H__

#include "OgreCamera.h"
#include "OgreSceneNode.h"
#include "OgreFrameListener.h"
#include <QKeyEvent>
#include <QMouseEvent>

// enum CameraStyle should be in other namespace than OgreBites::CameraStyle
namespace OgreQtBites
{
    enum CameraStyle   // enumerator values for different styles of camera movement
    {
        CS_FREELOOK,
        CS_ORBIT,
        CS_MANUAL
    };

    /*=============================================================================
    | Utility class for controlling the camera in samples.
    =============================================================================*/
    class SdkQtCameraMan
    {
    public:
        SdkQtCameraMan(Ogre::Camera* cam)
        : mCamera(0)
        , mTarget(0)
        , mOrbiting(false)
        , mZooming(false)
        , mTopSpeed(150)
        , mVelocity(Ogre::Vector3::ZERO)
        , mGoingForward(false)
        , mGoingBack(false)
        , mGoingLeft(false)
        , mGoingRight(false)
        , mGoingUp(false)
        , mGoingDown(false)
        , mFastMove(false)
        {

            setCamera(cam);
            setStyle(CS_FREELOOK);
        }

        virtual ~SdkQtCameraMan() {}

        /*-----------------------------------------------------------------------------
        | Swaps the camera on our camera man for another camera.
        -----------------------------------------------------------------------------*/
        virtual void setCamera(Ogre::Camera* cam)
        {
            mCamera = cam;
        }

        virtual Ogre::Camera* getCamera()
        {
            return mCamera;
        }

        /*-----------------------------------------------------------------------------
        | Sets the target we will revolve around. Only applies for orbit style.
        -----------------------------------------------------------------------------*/
        virtual void setTarget(Ogre::SceneNode* target)
        {
            if (target != mTarget)
            {
                mTarget = target;
                if(target)
                {
                    setYawPitchDist(Ogre::Degree(0), Ogre::Degree(15), 150);
                    mCamera->setAutoTracking(true, mTarget);
                }
                else
                {
                    mCamera->setAutoTracking(false);
                }

            }


        }

        virtual Ogre::SceneNode* getTarget()
        {
            return mTarget;
        }

        /*-----------------------------------------------------------------------------
        | Sets the spatial offset from the target. Only applies for orbit style.
        -----------------------------------------------------------------------------*/
        virtual void setYawPitchDist(Ogre::Radian yaw, Ogre::Radian pitch, Ogre::Real dist)
        {
            mCamera->setPosition(mTarget->_getDerivedPosition());
            mCamera->setOrientation(mTarget->_getDerivedOrientation());
            mCamera->yaw(yaw);
            mCamera->pitch(-pitch);
            mCamera->moveRelative(Ogre::Vector3(0, 0, dist));
        }

        /*-----------------------------------------------------------------------------
        | Sets the camera's top speed. Only applies for free-look style.
        -----------------------------------------------------------------------------*/
        virtual void setTopSpeed(Ogre::Real topSpeed)
        {
            mTopSpeed = topSpeed;
        }

        virtual Ogre::Real getTopSpeed()
        {
            return mTopSpeed;
        }

        /*-----------------------------------------------------------------------------
        | Sets the movement style of our camera man.
        -----------------------------------------------------------------------------*/
        virtual void setStyle(CameraStyle style)
        {
            if (mStyle != CS_ORBIT && style == CS_ORBIT)
            {
                setTarget(mTarget ? mTarget : mCamera->getSceneManager()->getRootSceneNode());
                mCamera->setFixedYawAxis(true);
                manualStop();
                setYawPitchDist(Ogre::Degree(0), Ogre::Degree(15), 150);
            }
            else if (mStyle != CS_FREELOOK && style == CS_FREELOOK)
            {
                mCamera->setAutoTracking(false);
                mCamera->setFixedYawAxis(true);
            }
            else if (mStyle != CS_MANUAL && style == CS_MANUAL)
            {
                mCamera->setAutoTracking(false);
                manualStop();
            }
            mStyle = style;

        }

        virtual CameraStyle getStyle()
        {
            return mStyle;
        }

        /*-----------------------------------------------------------------------------
        | Manually stops the camera when in free-look mode.
        -----------------------------------------------------------------------------*/
        virtual void manualStop()
        {
            if (mStyle == CS_FREELOOK)
            {
                mGoingForward = false;
                mGoingBack = false;
                mGoingLeft = false;
                mGoingRight = false;
                mGoingUp = false;
                mGoingDown = false;
                mVelocity = Ogre::Vector3::ZERO;
            }
        }

        virtual bool frameRenderingQueued(const Ogre::FrameEvent& evt)
        {
            if (mStyle == CS_FREELOOK)
            {
                // build our acceleration vector based on keyboard input composite
                Ogre::Vector3 accel = Ogre::Vector3::ZERO;
                if (mGoingForward) accel += mCamera->getDirection();
                if (mGoingBack) accel -= mCamera->getDirection();
                if (mGoingRight) accel += mCamera->getRight();
                if (mGoingLeft) accel -= mCamera->getRight();
                if (mGoingUp) accel += mCamera->getUp();
                if (mGoingDown) accel -= mCamera->getUp();

                // if accelerating, try to reach top speed in a certain time
                Ogre::Real topSpeed = mFastMove ? mTopSpeed * 20 : mTopSpeed;
                if (accel.squaredLength() != 0)
                {
                    accel.normalise();
                    mVelocity += accel * topSpeed * evt.timeSinceLastFrame * 10;
                }
                // if not accelerating, try to stop in a certain time
                else mVelocity -= mVelocity * evt.timeSinceLastFrame * 10;

                Ogre::Real tooSmall = std::numeric_limits<Ogre::Real>::epsilon();

                // keep camera velocity below top speed and above epsilon
                if (mVelocity.squaredLength() > topSpeed * topSpeed)
                {
                    mVelocity.normalise();
                    mVelocity *= topSpeed;
                }
                else if (mVelocity.squaredLength() < tooSmall * tooSmall)
                    mVelocity = Ogre::Vector3::ZERO;

                if (mVelocity != Ogre::Vector3::ZERO) mCamera->move(mVelocity * evt.timeSinceLastFrame);
            }

            return true;
        }

        /*-----------------------------------------------------------------------------
        | Processes key presses for free-look style movement.
        -----------------------------------------------------------------------------*/
        virtual void injectKeyDown(const QKeyEvent& evt)
        {
            if (mStyle == CS_FREELOOK)
            {
                if (evt.key() == Qt::Key_W || evt.key() == Qt::Key_Up) mGoingForward = true;
                else if (evt.key() == Qt::Key_S || evt.key() == Qt::Key_Down) mGoingBack = true;
                else if (evt.key() == Qt::Key_A || evt.key() == Qt::Key_Left) mGoingLeft = true;
                else if (evt.key() == Qt::Key_D || evt.key() == Qt::Key_Right) mGoingRight = true;
                else if (evt.key() == Qt::Key_PageUp) mGoingUp = true;
                else if (evt.key() == Qt::Key_PageDown) mGoingDown = true;
                else if (evt.key() == Qt::Key_Shift) mFastMove = true;
            }
        }

        /*-----------------------------------------------------------------------------
        | Processes key releases for free-look style movement.
        -----------------------------------------------------------------------------*/
        virtual void injectKeyUp(const QKeyEvent& evt)
        {
            if (mStyle == CS_FREELOOK)
            {
                if (evt.key() == Qt::Key_W || evt.key() == Qt::Key_Up) mGoingForward = false;
                else if (evt.key() == Qt::Key_S || evt.key() == Qt::Key_Down) mGoingBack = false;
                else if (evt.key() == Qt::Key_A || evt.key() == Qt::Key_Left) mGoingLeft = false;
                else if (evt.key() == Qt::Key_D || evt.key() == Qt::Key_Right) mGoingRight = false;
                else if (evt.key() == Qt::Key_PageUp) mGoingUp = false;
                else if (evt.key() == Qt::Key_PageDown) mGoingDown = false;
                else if (evt.key() == Qt::Key_Shift) mFastMove = false;
            }
        }

        /*-----------------------------------------------------------------------------
        | Processes mouse movement differently for each style.
        -----------------------------------------------------------------------------*/
        virtual void injectMouseMove(int relX, int relY)
        {
//            static int lastX = evt.x();
//            static int lastY = evt.y();
//            int relX = evt.x() - lastX;
//            int relY = evt.y() - lastY;
//            lastX = evt.x();
//            lastY = evt.y();
            if (mStyle == CS_ORBIT)
            {
                Ogre::Real dist = (mCamera->getPosition() - mTarget->_getDerivedPosition()).length();

                if (mOrbiting)   // yaw around the target, and pitch locally
                {
                    mCamera->setPosition(mTarget->_getDerivedPosition());

                    mCamera->yaw(Ogre::Degree(-relX * 0.025f));
                    mCamera->pitch(Ogre::Degree(-relY * 0.025f));

                    mCamera->moveRelative(Ogre::Vector3(0, 0, dist));

                    // don't let the camera go over the top or around the bottom of the target
                }
                else if (mZooming)  // move the camera toward or away from the target
                {
                    // the further the camera is, the faster it moves
                    mCamera->moveRelative(Ogre::Vector3(0, 0, relY * 0.004f * dist));
                }
            }
            else if (mStyle == CS_FREELOOK)
            {
                mCamera->yaw(Ogre::Degree(-relX * 0.15f));
                mCamera->pitch(Ogre::Degree(-relY * 0.15f));
            }
        }

        /*-----------------------------------------------------------------------------
        | Processes mouse movement differently for each style.
        -----------------------------------------------------------------------------*/
        virtual void injectWheelMove(const QWheelEvent& evt)
        {
            int relZ = evt.delta();
            if (mStyle == CS_ORBIT)
            {
                Ogre::Real dist = (mCamera->getPosition() - mTarget->_getDerivedPosition()).length();

                if (relZ != 0)  // move the camera toward or away from the target
                {
                    // the further the camera is, the faster it moves
                    mCamera->moveRelative(Ogre::Vector3(0, 0, -relZ * 0.0008f * dist));
                }
            }
        }

        /*-----------------------------------------------------------------------------
        | Processes mouse presses. Only applies for orbit style.
        | Left button is for orbiting, and right button is for zooming.
        -----------------------------------------------------------------------------*/
        virtual void injectMouseDown(const QMouseEvent& evt)
        {
            if (mStyle == CS_ORBIT)
            {
                if (evt.buttons() & Qt::LeftButton) mOrbiting = true;
                else if (evt.buttons() & Qt::RightButton) mZooming = true;
            }
        }

        /*-----------------------------------------------------------------------------
        | Processes mouse releases. Only applies for orbit style.
        | Left button is for orbiting, and right button is for zooming.
        -----------------------------------------------------------------------------*/
        virtual void injectMouseUp(const QMouseEvent& evt)
        {
            if (mStyle == CS_ORBIT)
            {
                if (evt.buttons() & Qt::LeftButton) mOrbiting = false;
                else if (evt.buttons() & Qt::RightButton) mZooming = false;
            }
        }

    protected:

        Ogre::Camera* mCamera;
        CameraStyle mStyle;
        Ogre::SceneNode* mTarget;
        bool mOrbiting;
        bool mZooming;
        Ogre::Real mTopSpeed;
        Ogre::Vector3 mVelocity;
        bool mGoingForward;
        bool mGoingBack;
        bool mGoingLeft;
        bool mGoingRight;
        bool mGoingUp;
        bool mGoingDown;
        bool mFastMove;
    };
}

#endif

With our class set up, here is how we would use it as a standalone window:

/*

Place the include along with your other includes where you will be creating and/or calling the above QTOgreWindow:

*/


#include "QTOgreWindow.h"

/*

In the method you are creating/calling a QTOgreWindow:

*/

QTOgreWindow* ogreWindow = new QTOgreWindow();
ogreWindow->show();


If you wish to integrate this QWindow inside of a QWidget for use with another section/QWidget of Qt, you do this:

/*

Place the include along with your other includes where you will be creating and/or calling the above QTOgreWindow:

*/


#include "QTOgreWindow.h"

/*

In the method you are creating/calling a QTOgreWindow:

*/

QTOgreWindow* ogreWindow = new QTOgreWindow();
QWidget* renderingContainer = QWidget::createWindowContainer(ogreWindow);

/*

As an example, the below method places the QTOgreWindow we just created inside of a QTabWidget as a tab.

*/

mainTabs->addTab(renderingContainer, tr("New Ogre Window"));


And that's it!

Comments and edits welcome.