How to glutPostRedisplay on a window that is not the current window?

OpenGL OpenGL: Basic Coding
1

I have two windows. the upper window is taking user input and as a result of that input the lower window which is not the current window needs to get updated. However according to the manual page for glutPostRedisplay, that call only affects the top or current window. What is the equivalent call to force glut to update the lower window?
I would like to avoid bringing the lower one to the front momentarily and updating it and then sending it to the back again.
Thanks.

2

You might check out this old thread (first hit on a web search of “glut multi-window”):

Specifically:


	glutSetWindow( window_1 );
	glutPostRedisplay();  // Update screen with new rotation data
 
	glutSetWindow( window_2 );
	glutPostRedisplay();  // Update screen with new rotation data

Sure enough, the API is still there:

3

Great, thank you.