Hi,

Is it possible to use opengl to draw e.g. an OpenGL texture or a simple triangle inside an QGraphicsItem bounding rect?

I tried following, but the triangle is drawn outside of the bounding rect of the QGraphicsItem.

Qt Code: 
  1. class MyItem : public QGraphicsItem
  2. {
  3. public:
  4. 	MyItem( QGraphicsItem * parent = 0 ) : QGraphicsItem(parent),
  5. 	w(200), h(200)
  6. 	{}
  7.  
  8. 	void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
  9.     {
  10. 		painter->drawRect(boundingRect());
  11.  		painter->beginNativePainting();
  12.  
  13.  		glViewport(20, 20, w, h);    /* Reset The Current Viewport And Perspective Transformation */
  14. 		glMatrixMode(GL_PROJECTION);
  15. 		glLoadIdentity();
  16. 		gluPerspective(45.0f, (GLfloat)w / (GLfloat)h, 0.1f, 100.0f);
  17. 		glMatrixMode(GL_MODELVIEW); 
  18.  
  19. 		glLoadIdentity();
  20. 		glTranslatef(0.0f , 0.0f, -6.0f);
  21. 		glBegin(GL_TRIANGLES);
  22. 			glVertex3f(0.0f, 1.0f, 0.0f);
  23. 			glVertex3f(-1.0f, -1.0f, 0.0f);
  24. 			glVertex3f(1.0f, -1.0f, 0.0f);
  25. 		glEnd();
  26.  
  27.  		painter->endNativePainting();
  28.     }
  29.  
  30.     QRectF boundingRect () const{
  31. 		return QRectF(20,20,w,h);
  32.     }
  33.  
  34. private:
  35.  
  36. 	int w, h;
  37. };
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