glutSetWindow (3) - Linux Manuals

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

NAME

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

LIBRARY

OpenGLUT - window

SYNOPSIS

In openglut.h Ft void Fn glutSetWindow int ID

PARAMETERS

Bf Em
 ID Ef
       Window identifier

DESCRIPTION

Sets the Bf Li
 current window Ef
  to  Bf Sy
 ID. Ef
 

All OpenGL rendering goes to the Bf Li
 current window Ef
 . Many OpenGLUT functions also implicitly use the Bf Li
 current window Ef
 .

Many OpenGLUT callback operations are tied to a window. When your callback is invoked, OpenGLUT will set that particular window to be the Bf Li
 current window Ef
 . 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 Bf Em
 always Ef
  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 Bf Li
 current window Ef
  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 Bf Li
 current window Ef
  and draw immediately.  This is not always advisable, but may be practical.

It is an error to set the Bf Li
 current window Ef
  to a non-existant window (e.g., one that you have closed). A warning will be printed on Bf Sy
 stderr Ef
 if you try to do so, and the Bf Li
 current window Ef
  should be unchanged.