glXCopyContext(3G) OpenGL Reference - GLX glXCopyContext(3G)NAMEglXCopyContext - copy state from one rendering context to another
C SPECIFICATION
void glXCopyContext( Display *dpy,
GLXContext src,
GLXContext dst,
unsigned long mask )
PARAMETERS
dpy Specifies the connection to the X server.
src Specifies the source context.
dst Specifies the destination context.
mask Specifies which portions of src state are to be copied to dst.
DESCRIPTIONglXCopyContext copies selected groups of state variables from src to dst.
mask indicates which groups of state variables are to be copied. mask
contains the bitwise OR of the same symbolic names that are passed to the
GL command glPushAttrib. The single symbolic constant GL_ALL_ATTRIB_BITS
can be used to copy the maximum possible portion of rendering state.
The copy can be done only if the renderers named by src and dst share an
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.
Not all values for GL state can be copied. For example, pixel pack and
unpack state, render mode state, and select and feedback state are not
copied. The state that can be copied is exactly the state that is
manipulated by the GL command glPushAttrib.
An implicit glXFlush is done by glXCopyContext if src is the current
context for the calling thread.
NOTES
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.
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
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glXCopyContext(3G) OpenGL Reference - GLX glXCopyContext(3G)
group is equivalent to a process.
ERRORS
BadMatch is generated if rendering contexts src and dst do not share an
address space or were not created with respect to the same screen.
BadAccess is generated if dst is current to any thread (including the
calling thread) at the time glXCopyContext is called.
GLXBadCurrentWindow is generated if src is the current context and the
current drawable is a window that is no longer valid.
GLXBadContext is generated if either src or dst is not a valid GLX
context.
BadValue is generated if undefined mask bits are specified.
MACHINE DEPENDENCIES
On all SGI systems, src must be the current context and, except in the
case of direct rendering contexts on InfiniteReality, RealityEngine,
RealityEngine2, and VTX systems, dst must have been made current to some
thread prior to the copy.
On RealityEngine, RealityEngine2, and VTX, on InfiniteReality, on High
Impact and Maximum Impact, on Solid Impact systems, on O2 systems, and on
Octane2 VPro systems, it is not possible to use a context for rendering
to both windows and pixmaps.
SEE ALSO
glPushAttrib, glXCreateContext, glXIsDirect
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