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NAME
     glXCreateContext - create a new GLX rendering context


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


PARAMETERS
     dpy        Specifies the connection to the X server.

     vis        Specifies  the  visual  that  defines  the  frame
                buffer  resources available to the rendering con-
                text.  It is a pointer to an  XVisualInfo  struc-
                ture, 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 pos-
                sible (True) or through the X server (False).

DESCRIPTION
     glXCreateContext creates a GLX rendering context and returns
     its  handle.   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 rendering 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
     definitions are shared by context shareList and by the newly
     created context.  An arbitrary number of contexts can  share
     a  single  display-list  space.  However, all rendering con-
     texts that share a single display-list space must themselves
     exist  in  the  same  address space.  Two rendering 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 subprocess group is equivalent to a pro-
     cess.

     It may not be possible to render to  a  GLX  pixmap  with  a
     direct rendering 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 speci-
     fied 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

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