glXCreateContext(3G) OpenGL Reference - GLX glXCreateContext(3G)
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 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 and
texture objects. 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 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 and the connection is to an X
server that is local. 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 cannot be used to render to GLX pixmaps.
If shareList is not NULL, then all display-list and texture object
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 and texture object space as long as they 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
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glXCreateContext(3G) OpenGL Reference - GLX glXCreateContext(3G)
rendering contexts to share an address space.
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 process.
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 (e.g., if the 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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