glXMakeCurrent.3gl

Name

  glXMakeCurrent - attach a GLX	context	to a window or a GLX pixmap

C Specification

  Bool glXMakeCurrent( Display *dpy,
		       GLXDrawable drawable,
		       GLXContext ctx )

Parameters

  dpy	    Specifies the connection to	the X server.


  drawable  Specifies a	GLX drawable.  Must be either an X window ID or	a GLX
	    pixmap ID.


  ctx	    Specifies a	GLX rendering context that is to be attached to
	    drawable.

Description

  glXMakeCurrent does two things: It makes ctx the current GLX rendering
  context of the calling thread, replacing the previously current context if
  there	was one, and it	attaches ctx to	a GLX drawable,	either a window	or a
  GLX pixmap.  As a result of these two	actions, subsequent OpenGL rendering
  calls	use rendering context ctx to modify GLX	drawable drawable.  Because
  glXMakeCurrent always	replaces the current rendering context with ctx,
  there	can be only one	current	context	per thread.

  Pending commands to the previous context, if any, are	flushed	before it is
  released.

  The first time ctx is	made current to	any thread, its	viewport is set	to
  the full size	of drawable.  Subsequent calls by any thread to
  glXMakeCurrent with ctx have no effect on its	viewport.

  To release the current context without assigning a new one, call
  glXMakeCurrent with drawable and ctx set to None and NULL respectively.

  glXMakeCurrent returns True if it is successful, False otherwise.  If	False
  is returned, the previously current rendering	context	and drawable (if any)
  remain unchanged.

Notes

  A process is a single-execution environment, implemented in a	single
  address space, consisting of one or more threads.


  A thread is one of a set of subprocesses that	share a	single address space,
  but maintain separate	program	counters, stack	spaces,	and other related
  global data.	A thread that is the only member of its	subprocess group is
  equivalent to	a process.

Errors

  BadMatch is generated	if drawable was	not created with the same X screen
  and visual as	ctx.  It is also generated if drawable is None and ctx is not
  None.

  BadAccess is generated if ctx	was current to another thread at the time
  glXMakeCurrent was called.

  GLXBadDrawable is generated if drawable is not a valid GLX drawable.

  GLXBadContext	is generated if	ctx is not a valid GLX context.

  GLXBadContextState is	generated if glXMakeCurrent is called between a
  glBegin and the corresponding	call to	glEnd.

  GLXBadContextState is	also generated if the rendering	context	current	to
  the calling thread has OpenGL	renderer state GL_FEEDBACK or GL_SELECT.

  GLXBadCurrentWindow is generated if there are	pending	OpenGL commands	for
  the previous context and the current drawable	is a window that is no longer
  valid.

  BadAlloc may be generated if the server has delayed allocation of ancillary
  buffers until	glXMakeCurrent is called, only to find that it has
  insufficient resources to complete the allocation.

See Also

  glXCreateContext, glXCreateGLXPixmap

Introduction | Alphabetic | Specification

Last Edited: Fri Dec 6 11:18:03 EST 1996 by AFV
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