glutSetWindow man page

glutSetWindow — Select the <i>current window</i>


OpenGLUT - window


#include <openglut.h>

glutSetWindow(int ID);



Window identifier


Sets the

current window



All OpenGL rendering goes to the

current window

. Many OpenGLUT functions also implicitly use the

current window


Many OpenGLUT callback operations are tied to a window. When your callback is invoked, OpenGLUT will set that particular window to be the

current window

. However, some callbacks---such as that registered via glutIdleFunc()---do not have associated windows. If a callback is not associated to a particular window, then when OpenGLUT invokes that callback you should


use glutSetWindow() to select the appropriate window before doing any OpenGL rendering or doing any OpenGLUT window-related operations.

There may be cases when you can get away with assuming that the

current window

is unchanged since some prior time, but OpenGLUT has considerable liberaty with respect to when it invokes your functions. Also, your program may add more windows or more operations on other windows as you develop it.

Lastly, this is a convenient way to select among multiple windows for drawing without actually waiting for that window's display callback. Simply set the

current window

and draw immediately. This is not always advisable, but may be practical.

It is an error to set the

current window

to a non-existant window (e.g., one that you have closed). A warning will be printed on


if you try to do so, and the

current window

should be unchanged.

See Also



Referenced By


Explore man page connections for glutSetWindow(3).