How to Load 3D Object Model with OpenSceneGraph on wxWidgets

Today, I was able to load 3D Object Model with OpenSceneGraph on wxWidgets. This project used OpenSceneGraph-3.0, wxWidget 2.8.12, Windows 10 and Visual Studio 2010.  It was really fun. The code consist of wxOsgHello.cpp and wxOsgHello.h. Here is the code shown as below:


Filename: wxOsgHello.cpp

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
#pragma hdrstop
#endif

#ifndef WX_PRECOMP
#include "wx/wx.h"
#endif

// For wxCURSOR_BLANK below, but isn't used a.t.m.
//#ifdef WIN32
//#include "wx/msw/wx.rc"
//#endif

#include "wxOsgHello.h"


#include <osgViewer/ViewerEventHandlers>
#include <osgGA/TrackballManipulator>
#include <osgDB/ReadFile>
#include <wx/image.h>
#include <wx/menu.h>

#include <iostream>

// `Main program' equivalent, creating windows and returning main app frame
bool wxOsgApp::OnInit()
{
    if (argc<2)
    {
        std::cout << wxString(argv[0]).mb_str() <<": requires filename argument." << std::endl;
        return false;
    }

    int width = 800;
    int height = 600;

    // Create the main frame window

    MainFrame *frame = new MainFrame(NULL, wxT("wxWidgets OSG Sample"),
        wxDefaultPosition, wxSize(width, height));

    // create osg canvas
    //    - initialize

    int attributes[7];
    attributes[0] = int(WX_GL_DOUBLEBUFFER);
    attributes[1] = WX_GL_RGBA;
    attributes[2] = WX_GL_DEPTH_SIZE;
    attributes[3] = 8;
    attributes[4] = WX_GL_STENCIL_SIZE;
    attributes[5] = 8;
    attributes[6] = 0;

    OSGCanvas *canvas = new OSGCanvas(frame, wxID_ANY, wxDefaultPosition,
        wxSize(width, height), wxSUNKEN_BORDER, wxT("osgviewerWX"), attributes);

    GraphicsWindowWX* gw = new GraphicsWindowWX(canvas);

    canvas->SetGraphicsWindow(gw);

    osgViewer::Viewer *viewer = new osgViewer::Viewer;
    viewer->getCamera()->setGraphicsContext(gw);
    viewer->getCamera()->setViewport(0,0,width,height);
    viewer->addEventHandler(new osgViewer::StatsHandler);
    viewer->setThreadingModel(osgViewer::Viewer::SingleThreaded);

    // load the scene.
    wxString fname(argv[1]);
    osg::ref_ptr<osg::Node> loadedModel = osgDB::readNodeFile(std::string(fname.mb_str()));
    if (!loadedModel)
    {
        std::cout << argv[0] <<": No data loaded." << std::endl;
        return false;
    }

    viewer->setSceneData(loadedModel.get());
    viewer->setCameraManipulator(new osgGA::TrackballManipulator);
    frame->SetViewer(viewer);

    /* Show the frame */
    frame->Show(true);

    return true;
}

IMPLEMENT_APP(wxOsgApp)

BEGIN_EVENT_TABLE(MainFrame, wxFrame)
    EVT_IDLE(MainFrame::OnIdle)
END_EVENT_TABLE()

/* My frame constructor */
MainFrame::MainFrame(wxFrame *frame, const wxString& title, const wxPoint& pos,
    const wxSize& size, long style)
    : wxFrame(frame, wxID_ANY, title, pos, size, style)
{
}

void MainFrame::SetViewer(osgViewer::Viewer *viewer)
{
    _viewer = viewer;
}

void MainFrame::OnIdle(wxIdleEvent &event)
{
    if (!_viewer->isRealized())
        return;

    _viewer->frame();

    event.RequestMore();
}

BEGIN_EVENT_TABLE(OSGCanvas, wxGLCanvas)
    EVT_SIZE                (OSGCanvas::OnSize)
    EVT_PAINT               (OSGCanvas::OnPaint)
    EVT_ERASE_BACKGROUND    (OSGCanvas::OnEraseBackground)

    EVT_CHAR                (OSGCanvas::OnChar)
    EVT_KEY_UP              (OSGCanvas::OnKeyUp)

    EVT_ENTER_WINDOW        (OSGCanvas::OnMouseEnter)
    EVT_LEFT_DOWN           (OSGCanvas::OnMouseDown)
    EVT_MIDDLE_DOWN         (OSGCanvas::OnMouseDown)
    EVT_RIGHT_DOWN          (OSGCanvas::OnMouseDown)
    EVT_LEFT_UP             (OSGCanvas::OnMouseUp)
    EVT_MIDDLE_UP           (OSGCanvas::OnMouseUp)
    EVT_RIGHT_UP            (OSGCanvas::OnMouseUp)
    EVT_MOTION              (OSGCanvas::OnMouseMotion)
    EVT_MOUSEWHEEL          (OSGCanvas::OnMouseWheel)
END_EVENT_TABLE()

OSGCanvas::OSGCanvas(wxWindow *parent, wxWindowID id,
    const wxPoint& pos, const wxSize& size, long style, const wxString& name, int *attributes)
    : wxGLCanvas(parent, id, pos, size, style|wxFULL_REPAINT_ON_RESIZE, name, attributes)
{
    // default cursor to standard
    _oldCursor = *wxSTANDARD_CURSOR;
}

OSGCanvas::~OSGCanvas()
{
}

void OSGCanvas::OnPaint( wxPaintEvent& WXUNUSED(event) )
{
    /* must always be here */
    wxPaintDC dc(this);
}

void OSGCanvas::OnSize(wxSizeEvent& event)
{
    // this is also necessary to update the context on some platforms
    wxGLCanvas::OnSize(event);

    // set GL viewport (not called by wxGLCanvas::OnSize on all platforms...)
    int width, height;
    GetClientSize(&width, &height);

    if (_graphics_window.valid())
    {
        // update the window dimensions, in case the window has been resized.
        _graphics_window->getEventQueue()->windowResize(0, 0, width, height);
        _graphics_window->resized(0,0,width,height);
    }
}

void OSGCanvas::OnEraseBackground(wxEraseEvent& WXUNUSED(event))
{
    /* Do nothing, to avoid flashing on MSW */
}

void OSGCanvas::OnChar(wxKeyEvent &event)
{
#if wxUSE_UNICODE
    int key = event.GetUnicodeKey();
#else
    int key = event.GetKeyCode();
#endif

    if (_graphics_window.valid())
        _graphics_window->getEventQueue()->keyPress(key);

    // If this key event is not processed here, we should call
    // event.Skip() to allow processing to continue.
}

void OSGCanvas::OnKeyUp(wxKeyEvent &event)
{
#if wxUSE_UNICODE
    int key = event.GetUnicodeKey();
#else
    int key = event.GetKeyCode();
#endif

    if (_graphics_window.valid())
        _graphics_window->getEventQueue()->keyRelease(key);

    // If this key event is not processed here, we should call
    // event.Skip() to allow processing to continue.
}

void OSGCanvas::OnMouseEnter(wxMouseEvent &event)
{
    // Set focus to ourselves, so keyboard events get directed to us
    SetFocus();
}

void OSGCanvas::OnMouseDown(wxMouseEvent &event)
{
    if (_graphics_window.valid())
    {
        _graphics_window->getEventQueue()->mouseButtonPress(event.GetX(), event.GetY(),
            event.GetButton());
    }
}

void OSGCanvas::OnMouseUp(wxMouseEvent &event)
{
    if (_graphics_window.valid())
    {
        _graphics_window->getEventQueue()->mouseButtonRelease(event.GetX(), event.GetY(),
            event.GetButton());
    }
}

void OSGCanvas::OnMouseMotion(wxMouseEvent &event)
{
    if (_graphics_window.valid())
        _graphics_window->getEventQueue()->mouseMotion(event.GetX(), event.GetY());
}

void OSGCanvas::OnMouseWheel(wxMouseEvent &event)
{
    int delta = event.GetWheelRotation() / event.GetWheelDelta() * event.GetLinesPerAction();

    if (_graphics_window.valid()) {
        _graphics_window->getEventQueue()->mouseScroll(
            delta>0 ? 
            osgGA::GUIEventAdapter::SCROLL_UP : 
            osgGA::GUIEventAdapter::SCROLL_DOWN);
    }
}

void OSGCanvas::UseCursor(bool value)
{
    if (value)
    {
        // show the old cursor
        SetCursor(_oldCursor);
    }
    else
    {
        // remember the old cursor
        _oldCursor = GetCursor();

        // hide the cursor
        //    - can't find a way to do this neatly, so create a 1x1, transparent image
        wxImage image(1,1);
        image.SetMask(true);
        image.SetMaskColour(0, 0, 0);
        wxCursor cursor(image);
        SetCursor(cursor);

        // On wxGTK, only works as of version 2.7.0
        // (http://trac.wxwidgets.org/ticket/2946)
        // SetCursor( wxStockCursor( wxCURSOR_BLANK ) );
    }
}

GraphicsWindowWX::GraphicsWindowWX(OSGCanvas *canvas)
{
    _canvas = canvas;

    _traits = new GraphicsContext::Traits;

    wxPoint pos = _canvas->GetPosition();
    wxSize  size = _canvas->GetSize();

    _traits->x = pos.x;
    _traits->y = pos.y;
    _traits->width = size.x;
    _traits->height = size.y;

    init();
}

GraphicsWindowWX::~GraphicsWindowWX()
{
}

void GraphicsWindowWX::init()
{
    if (valid())
    {
        setState( new osg::State );
        getState()->setGraphicsContext(this);

        if (_traits.valid() && _traits->sharedContext)
        {
            getState()->setContextID( _traits->sharedContext->getState()->getContextID() );
            incrementContextIDUsageCount( getState()->getContextID() );
        }
        else
        {
            getState()->setContextID( osg::GraphicsContext::createNewContextID() );
        }
    }
}

void GraphicsWindowWX::grabFocus()
{
    // focus the canvas
    //_canvas->SetFocus();
}

void GraphicsWindowWX::grabFocusIfPointerInWindow()
{
    // focus this window, if the pointer is in the window
   /* wxPoint pos = wxGetMousePosition();
    if (wxFindWindowAtPoint(pos) == _canvas)
        _canvas->SetFocus();*/
}

void GraphicsWindowWX::useCursor(bool cursorOn)
{
    _canvas->UseCursor(cursorOn);
}

bool GraphicsWindowWX::makeCurrentImplementation()
{
    _canvas->SetCurrent();
    return true;
}

void GraphicsWindowWX::swapBuffersImplementation()
{
    _canvas->SwapBuffers();
}

Filename: wxOsgHello.h

#ifndef _WXSIMPLEVIEWERWX_H_
#define _WXSIMPLEVIEWERWX_H_

#include "wx/defs.h"
#include "wx/app.h"
#include "wx/cursor.h"
#include "wx/glcanvas.h"
#include <osgViewer/Viewer>
#include <string>

class GraphicsWindowWX;

class OSGCanvas : public wxGLCanvas
{
public:
    OSGCanvas(wxWindow *parent, wxWindowID id = wxID_ANY,
        const wxPoint& pos = wxDefaultPosition,
        const wxSize& size = wxDefaultSize, long style = 0,
        const wxString& name = wxT("TestGLCanvas"),
        int *attributes = 0);

    virtual ~OSGCanvas();

    void SetGraphicsWindow(osgViewer::GraphicsWindow *gw)   { _graphics_window = gw; }

    void OnPaint(wxPaintEvent& event);
    void OnSize(wxSizeEvent& event);
    void OnEraseBackground(wxEraseEvent& event);

    void OnChar(wxKeyEvent &event);
    void OnKeyUp(wxKeyEvent &event);

    void OnMouseEnter(wxMouseEvent &event);
    void OnMouseDown(wxMouseEvent &event);
    void OnMouseUp(wxMouseEvent &event);
    void OnMouseMotion(wxMouseEvent &event);
    void OnMouseWheel(wxMouseEvent &event);

    void UseCursor(bool value);

private:
    DECLARE_EVENT_TABLE()

    osg::ref_ptr<osgViewer::GraphicsWindow> _graphics_window;

    wxCursor _oldCursor;
};

class GraphicsWindowWX : public osgViewer::GraphicsWindow
{
public:
    GraphicsWindowWX(OSGCanvas *canvas);
    ~GraphicsWindowWX();

    void init();

    //
    // GraphicsWindow interface
    //
    void grabFocus();
    void grabFocusIfPointerInWindow();
    void useCursor(bool cursorOn);

    bool makeCurrentImplementation();
    void swapBuffersImplementation();

    // not implemented yet...just use dummy implementation to get working.
    virtual bool valid() const { return true; }
    virtual bool realizeImplementation() { return true; }
    virtual bool isRealizedImplementation() const  { return _canvas->IsShownOnScreen(); }
    virtual void closeImplementation() {}
    virtual bool releaseContextImplementation() { return true; }

private:
    // XXX need to set _canvas to NULL when the canvas is deleted by
    // its parent. for this, need to add event handler in OSGCanvas
    OSGCanvas*  _canvas;
};

class MainFrame : public wxFrame
{
public:
    MainFrame(wxFrame *frame, const wxString& title, const wxPoint& pos,
        const wxSize& size, long style = wxDEFAULT_FRAME_STYLE);

    void SetViewer(osgViewer::Viewer *viewer);
    void OnIdle(wxIdleEvent& event);

private:
    osg::ref_ptr<osgViewer::Viewer> _viewer;

    DECLARE_EVENT_TABLE()
};

/* Define a new application type */
class wxOsgApp : public wxApp
{
public:
    bool OnInit();
};

#endif // _WXSIMPLEVIEWERWX_H_

Project Configuration
Under Visual Studio 2010, open your project properties

Tab Debugging:
    Command Arguments:
    E:/osg/OpenSceneGraph_Data/dumptruck.osg

Tab C/C++:
    Additional Include Directories:
    E:\osg\3rdParty-x64-Release\include;E:\osg\3rdParty-x64-Release\lib\mswu
    Preprocessor:
    WIN32;NDEBUG;__WXMSW__;_WINDOWS;_WINSOCKAPI_

Tab Linker:
   Additional Libraries Directories:
   E:\osg\3rdParty-x64-Release\lib\

Input:
opengl32.lib;OpenThreads.lib;osg.lib;osgDB.lib;osgUtil.lib;osgGA.lib;osgFX.lib;osgViewer.lib;osgText.lib;osgManipulator.lib;osgSim.lib;osgParticle.lib;osgShadow.lib;wxtiff.lib;wxjpeg.lib;wxpng.lib;wxzlib.lib;wxexpat.lib;wxregexu.lib;wxbase28u.lib;wxmsw28u_core.lib;wxmsw28u_adv.lib;wxcode_msw28u_propgrid.lib;wxbase28u_xml.lib;wxmsw28u_xrc.lib;wxbase28u_net.lib;wxmsw28u_aui.lib;wxmsw28u_gl.lib;wxmsw28u_html.lib;wxmsw28u_media.lib;wxmsw28u_qa.lib;


Compile and run, if you are successfully then you will get result as below

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