Quote Originally Posted by tbscope View Post
I can't see a problem in the stack trace.

Can you post the full code please (make it minimal and compilable)?
Once again thanks for the reply...

I have attached the code along with this mail, and also I have added the snippet of code for your reference...

Qt Code: 
  1. //main.cpp
  2. #include "openglsceneexample.h"
  3.  
  4. #include <QtGui>
  5. #include <QApplication>
  6.  
  7. int main(int argc, char *argv[])
  8. {
  9.     QApplication a(argc, argv);
  10.     OpenGLSceneExample w;
  11.     w.show();
  12.     return a.exec();
  13. }
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Qt Code: 
  1. //openglsceneexample.cpp
  2.  
  3. #include "openglsceneexample.h"
  4.  
  5. #include <QtGui>
  6. #include <QGLWidget>
  7.  
  8. ////////////////////////////////////////////////////////////////////////////////////////////////
  9. //////////////////// OPEN GL WIDGET
  10.  
  11. CEasyGLWidget::CEasyGLWidget(QWidget *parent)
  12. : QGLWidget(QGLFormat(QGL::SampleBuffers/*|QGL::AlphaChannel|QGL::HasOverlay|QGL::Rgba*/),parent) 
  13.  
  14. {
  15. 	m_pOGLObject = 0;
  16. }
  17.  
  18. CEasyGLWidget::~CEasyGLWidget()
  19. {
  20.  
  21. }
  22.  
  23.  
  24. /*! \brief Draws a single circular or elliptical arc.
  25.  * 
  26.  *\param  cx 			Upper Left corner of the in x coordinates
  27.  *\param  cy 			Upper Left corner of the in y coordinates
  28.  *\param  r				Radius of the arc.
  29.  *\param  start_angle 	Start position in angles (radian)
  30.  *\param  arc_angle 	Angle of the Arc in radian
  31.  *\param  num_segments  Point count, which represent the arc
  32.  */
  33. void CEasyGLWidget::DrawArc(GLdouble cx, GLdouble cy, GLdouble r, GLdouble start_angle, GLdouble arc_angle, int num_segments)
  34. {
  35. 	//Theta is calculated from the arc angle, the -1 bit comes from the fact that the arc is open 
  36. 	GLdouble theta = arc_angle / GLdouble(num_segments -1);
  37. 	GLdouble tangetial_factor = tanf(theta);
  38.  
  39. 	GLdouble radial_factor = cosf(theta);
  40.  
  41. 	//start at the start angle
  42. 	GLdouble  x = r * cosf(start_angle);
  43. 	GLdouble  y =  r * sinf(start_angle);
  44.  
  45. 	glBegin(GL_LINE_STRIP);
  46.  
  47. 	for(int i = 0; i < num_segments; i++)
  48. 	{
  49. 		glVertex2f(x + cx + r, y + cy +r); //, 0.5);
  50.  
  51. 		GLdouble tx = -y;
  52. 		GLdouble ty = x;
  53.  
  54. 		x += tx * tangetial_factor;
  55. 		y += ty * tangetial_factor;
  56.  
  57. 		x *= radial_factor;
  58. 		y *= radial_factor;
  59. 	}
  60.  
  61. 	glEnd();
  62. }
  63.  
  64.  
  65. /*! \brief Draws a single line.
  66.  * 
  67.  * \param[in] cStartPoint Start Point of the line to be drawn.
  68.  * \param[in] cDestPoint  Destination Point of the line to be drawn.
  69.  */
  70. void CEasyGLWidget::DrawLine(QPointF cStartPoint, QPointF cDestPoint)
  71. {
  72. 	glBegin(GL_LINE_STRIP);
  73.  
  74. 	glVertex2f(cStartPoint.rx(), cStartPoint.ry()); 
  75. 	glVertex2f(cDestPoint.rx(), cDestPoint.ry());
  76.  
  77. 	glEnd();
  78. }
  79.  
  80. void CEasyGLWidget::initializeGL()
  81. {
  82. 	qglClearColor( QColor(90,125,164,255)); //set background color
  83.  
  84. 	qglColor(QColor(255,0,0,255));
  85.  
  86. 	//create a display list containing information about the object we want to display
  87.     m_pOGLObject = glGenLists(1);
  88.  
  89.     glNewList(m_pOGLObject, GL_COMPILE);
  90.     DrawArc(0.0, 0.0, 30.0, 0.0, 2*PI, 60);
  91.  
  92.     DrawLine(QPointF(0.0,0.0), QPointF(200.0,200.0));
  93.     glEndList();
  94.  
  95. 	//activate alpha values for transparent colors of the bitmaps
  96. 	glEnable(GL_ALPHA_TEST);   
  97. 	glAlphaFunc(GL_GREATER,0.1);
  98.  
  99. 	//set up the rendering process to use a particular shading model and rendering flags:
  100. 	glShadeModel(GL_FLAT);
  101. }
  102.  
  103. void CEasyGLWidget::resizeGL(int iWidth, int iHeight)
  104. {
  105. 	 // Set size of the view port (display size)
  106. 	 glViewport(0,0,(int)MIN(iWidth,iHeight), (int)MIN(iWidth,iHeight)); // always use width=height
  107.  
  108. 	 glMatrixMode(GL_PROJECTION); //select protection matrix
  109. 	 glLoadIdentity();  //reset matrix position to start
  110.  
  111. 	 // Open gl always draws on the same matrix (width x height = fix defined hud size) 
  112. 	 // the size is defined by the Ortho Matrix. 
  113. 	 // This matrix is scaled to the destination size.
  114. 	 glOrtho(0, 400,400, 0, -1,1); 
  115.  
  116. 	 glMatrixMode(GL_MODELVIEW);  //select model view (result) matrix
  117. }
  118.  
  119. void CEasyGLWidget::paintGL()
  120. {
  121.  
  122.          glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear background using background color
  123.          glLoadIdentity();              //reset matrix position to start
  124.          glTranslatef(0.0, 0.0, 0.0) ; // move object to dest position
  125.          glCallList(m_pOGLObject);     // call the display list containing the rendering commands for the object
  126.  
  127.          QFont myFont("Verdana", 24);
  128.          myFont.setStyleStrategy(QFont.OpenGLCompatible);
  129.          renderText(20,20, 0,"test", myFont);
  130.  
  131. }
  132.  
  133.  
  134. /////////////////////////////////////////////////////////////////////////////////////////////
  135. /////////////////////////// ITEM
  136.  
  137. CEasyGraphicsItem::CEasyGraphicsItem(QWidget *parent)
  138. {
  139. 	m_OGLItem = new CEasyGLWidget();
  140. 	m_OGLItem->resize(200,200);
  141.         m_Pixmap = m_OGLItem->renderPixmap(600,600);
  142. }
  143. CEasyGraphicsItem::~CEasyGraphicsItem()
  144. {
  145.  
  146. }
  147.  
  148. void CEasyGraphicsItem::paint ( QPainter * painter, const QStyleOptionGraphicsItem * option, QWidget * widget)
  149. {
  150. 	 QRectF rect(0.0,0.0,200.0,200.0);
  151.  
  152. 	 //Works fine !!
  153. 	 //painter->drawArc(rect,0,16*360);
  154.  
  155. 	 // Open gl element is not displayed!!!
  156. 	//m_pPixmap = QPixmap::grabWidget(m_OGLItem,0,0,600,600); 
  157. 	m_Pixmap = m_OGLItem->renderPixmap(600,600);
  158. 	painter->drawPixmap(0,0,600,600,m_Pixmap); 
  159. 	//m_Image = m_OGLItem->grabFrameBuffer();
  160. 	//painter->drawImage(rect, m_Image); 
  161. }
  162.  
  163. QRectF CEasyGraphicsItem::boundingRect() const
  164. {	 
  165. 	return QRectF(0,0,600,600); //m_CurrWindowWidth,m_CurrWindowHeight);
  166. }
  167. ////////////////////////////////////////////////////////////////////////////////////////////////////
  168. ////////////////// MAIN Window
  169.  
  170. OpenGLSceneExample::OpenGLSceneExample(QWidget *parent)
  171.     : QMainWindow(parent)
  172. {
  173. //	ui.setupUi(this);
  174.  
  175. 	 m_pMainGraphicsScene = new QGraphicsScene();     
  176. 	 m_pMainGraphicsScene->setSceneRect(QRectF(0,0,630,630)); // Dummy window size
  177. 	 m_pMainGraphicsView = new QGraphicsView(m_pMainGraphicsScene);    
  178.  
  179. 	 m_pMainGLWidget = new QGLWidget();
  180. 	 //m_pMainGraphicsView->setViewport(m_pMainGLWidget);
  181.  
  182. 	 setCentralWidget(m_pMainGraphicsView); 
  183.  
  184.  
  185. 	 // Add open gl item  to view (not part of the scene!!) works fine!
  186. 	 /*m_OGLItem = new CEasyGLWidget(m_pMainGraphicsView); 
  187. 	 m_OGLItem->resize(400,400);
  188. 	 m_pMainGraphicsScene->addWidget(m_OGLItem);
  189. 	 */  
  190.  
  191. 	 // add graphics item which contain a open gl element
  192. 	 m_pItem = new CEasyGraphicsItem();
  193. 	 m_pMainGraphicsScene->addItem(m_pItem);
  194.  
  195.  
  196. }
  197.  
  198. OpenGLSceneExample::~OpenGLSceneExample()
  199. {
  200.  
  201. }
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Qt Code: 
  1. //openglsceneexample.h
  2.  
  3. #ifndef OPENGLSCENEEXAMPLE_H
  4. #define OPENGLSCENEEXAMPLE_H
  5.  
  6. #include <QtGui>
  7. #include <QGLWidget>
  8.  
  9. //#include "ui_openglsceneexample.h"
  10. #define MIN(a,b)  ((a < b)? a : b)
  11. #define PI            3.14159265358979323846 /*!< constant PI                         */
  12.  
  13. class CEasyGLWidget : public QGLWidget
  14. {
  15. 	Q_OBJECT
  16.  
  17. public:
  18.  
  19. 	CEasyGLWidget(QWidget *parent = 0);
  20. 	~CEasyGLWidget();
  21.  
  22. 	 void initializeGL();
  23. 	 void resizeGL(int w, int h);
  24. 	 void paintGL();
  25.  
  26. 	 void DrawArc(GLdouble cx, GLdouble cy, GLdouble r, GLdouble start_angle, GLdouble arc_angle, int num_segments);
  27. 	 void DrawLine(QPointF cStartPoint, QPointF cDestPoint);
  28. private:
  29.  
  30. 	GLuint             m_pOGLObject;  
  31.  
  32. };
  33.  
  34.  
  35. class CEasyGraphicsItem : public QGraphicsItem
  36. {
  37. 	//Q_OBJECT
  38.  
  39. public:
  40. 	CEasyGraphicsItem(QWidget *parent = 0);
  41. 	~CEasyGraphicsItem();
  42.  
  43. 	virtual QRectF boundingRect() const;	
  44.     virtual void paint ( QPainter * painter, const QStyleOptionGraphicsItem * option, QWidget * widget = 0 );
  45.  
  46. private:
  47. 	CEasyGLWidget *m_OGLItem;
  48. 	QPixmap m_Pixmap;
  49. 	QImage m_Image;
  50.  
  51. };
  52.  
  53.  
  54. class OpenGLSceneExample : public QMainWindow
  55. {
  56.     Q_OBJECT
  57.  
  58. public:
  59.     OpenGLSceneExample(QWidget *parent = 0);
  60.     ~OpenGLSceneExample();
  61.  
  62. private:
  63.     //Ui::OpenGLSceneExampleClass ui;
  64.  
  65.  
  66.     QGraphicsScene  *m_pMainGraphicsScene;     
  67.     QGraphicsView   *m_pMainGraphicsView;    
  68.     QGLWidget       *m_pMainGLWidget;          
  69.  
  70.     CEasyGraphicsItem *m_pItem;
  71.  
  72.     CEasyGLWidget *m_OGLItem;
  73. };
  74.  
  75. #endif // OPENGLSCENEEXAMPLE_H
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OpenGLScene.zip