[vtkusers] how to Using OpenGL with VTK???????

[叶元值]

Hi,
 	I would like to know if it is possible to use OpenGL commands in
 conjonction with VTK. Where should I place OpenGL commands in a VTK
 application ? For example, I would like to use fog and antialiasing.
For example, if I wanted to draw a OpenGL circle on top of my VTK terrain
 I would use this OpenGL code somewhere:

 				glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	// 
 				glLoadIdentity();							// Reset The matrix
 				glColor3ub(255, 0, 0);
     				glPushMatrix();
    				glTranslatef(x, y, 0);
   				glBegin(GL_LINE_LOOP);
        				for( float ang=0; ang <= 2*3.141; ang += 0.1)
 	   			{
        				glVertex2d( radius * cos(ang), radius * sin(ang));
	   			}
    				glEnd();
    				glPopMatrix();

What calls do I have to make to the vtkRenderWindow, vtkRenderer objects
to allow this to work, where would I place the OpenGL code?

 
 Thanks