glXCreateContext

GLXCREATECONTEXT()					   GLXCREATECONTEXT()



NAME
       glXCreateContext - create a new GLX rendering context


C SPECIFICATION
       GLXContext glXCreateContext( Display *dpy,
				    XVisualInfo *vis,
				    GLXContext shareList,
				    Bool direct )

       delim $$

PARAMETERS
       dpy	  Specifies the connection to the X server.

       vis	  Specifies   the   visual  that  defines  the	frame  buffer
		  resources available to the  rendering	 context.   It	is  a
		  pointer  to  an XVisualInfo structure, not a visual ID or a
		  pointer to a Visual.

       shareList  Specifies the context with which to  share  display  lists.
		  NULL indicates that no sharing is to take place.

       direct	  Specifies  whether  rendering	 is  to be done with a direct
		  connection to the graphics system  if	 possible  (True)  or
		  through the X server (False).

DESCRIPTION
       glXCreateContext	 creates a GLX rendering context and returns its han-
       dle.  This context can be used to render into  both  windows  and  GLX
       pixmaps.	  If  glXCreateContext	fails  to create a rendering context,
       NULL is returned.

       If direct is True, then a direct rendering context is created  if  the
       implementation supports direct rendering, if the connection is to an X
       server that is local, and if a direct rendering context is  available.
       (An  implementation  may	 return	 an  indirect  context when direct is
       True).  If direct is False, then	 a  rendering  context	that  renders
       through	the  X server is always created.  Direct rendering provides a
       performance advantage in some implementations.  However,	 direct	 ren-
       dering  contexts	 cannot	 be shared outside a single process, and they
       may be unable to render to GLX pixmaps.

       If shareList is not NULL, then all display-list	indexes	 and  defini-
       tions  are  shared  by context shareList and by the newly created con-
       text.  An arbitrary number of contexts can share a single display-list
       space.	However,  all rendering contexts that share a single display-
       list space must themselves exist in the same address space.  Two	 ren-
       dering contexts share an address space if both are nondirect using the
       same server, or if both are direct and  owned  by  a  single  process.
       Note  that  in the nondirect case, it is not necessary for the calling
       threads to share an address space, only for  their  related  rendering
       contexts to share an address space.

       If  the	GL version is 1.1 or greater, then all texture objects except
       object 0, are shared by any contexts that share display lists.

NOTES
       XVisualInfo is defined in Xutil.h.  It is a  structure  that  includes
       visual, visualID, screen, and depth elements.

       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  subpro-
       cess group is equivalent to a process.

       It may not be possible to render to a GLX pixmap with a direct render-
       ing context.

ERRORS
       NULL is returned if execution fails on the client side.

       BadMatch is generated if the context to be created would not share the
       address space or the screen of the context specified by shareList.

       BadValue	 is generated if vis is not a valid visual (for example, if a
       particular GLX implementation does not support it).

       GLXBadContext is generated if shareList is not a GLX  context  and  is
       not NULL.

       BadAlloc	 is generated if the server does not have enough resources to
       allocate the new context.

SEE ALSO
       glXDestroyContext, glXGetConfig, glXIsDirect, glXMakeCurrent




							   GLXCREATECONTEXT()