Hi,
I' trying to do a minimal OpenGL Image Viewer. Here's the code:
Qt Code: 
  1. class ImageWidget : public QGLWidget
  2. {
  3. 	QPixmap pixmap;
  4. public:
  5. 	ImageWidget(const QPixmap &_pixmap, const IO& _io, QWidget *parent=0)
  6. 		: QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
  7. 		, pixmap(_pixmap)
  8. 	{
  9. 	}
  10. 	void resizeGL(int w, int h)
  11. 	{
  12. 		glViewport(0, 0, w, h);
  13. 	}
  14. 	void paintGL()
  15. 	{
  16. 		glClear(GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER_BIT);
  17. 		glLoadIdentity();
  18.  
  19. 		glMatrixMode(GL_PROJECTION);
  20. 		glPushMatrix();
  21. 		glLoadIdentity();
  22.  
  23. 		glOrtho(0, width(), 0, height(), -1, 1);
  24. 		glMatrixMode(GL_MODELVIEW);
  25. 		glPushMatrix();
  26. 		glLoadIdentity();
  27.  
  28. 		bindTexture ( pixmap, GL_TEXTURE_2D, GL_RGBA );
  29. 		glBegin (GL_QUADS);
  30. 			glTexCoord2f (0.0, 0.0);		glVertex3f (10.0,		10.0,		0.0);
  31. 			glTexCoord2f (1.0, 0.0);		glVertex3f (width()-10,	10.0,		0.0);
  32. 			glTexCoord2f (1.0, 1.0);		glVertex3f (width()-10,	height()-10,	0.0);
  33. 			glTexCoord2f (0.0, 1.0);		glVertex3f (10.0,		height()-10,	0.0);
  34. 		glEnd ();
  35. 		/*glBegin(GL_TRIANGLES);
  36. 			glColor3ub(255, 0, 0);
  37. 			glVertex2d(0, 0);
  38. 			glColor3ub(0, 255, 0);
  39. 			glVertex2d(width(),0);
  40. 			glColor3ub(0, 0, 255);
  41. 			glVertex2d(width()/2, height());
  42. 		glEnd();*/
  43. 	}
  44. };
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The problem is I just see a white rectangle instead of the image. The commented code draws a triangle just fine, so I seem to have set up the viewport correctly.
I'm probably making some very simple mistake, so I'm thankful for any suggestions!

btw. Should I move any code from paintGL() to initGL()? I'm not sure if I have to make all of these calls every time I render the scene.