Manpages OpenGL - glXMakeCurrent

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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 GL rendering calls use rendering context ctx to modify GLX drawable drawable (for reading and writing). 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 set to None and ctx set to NULL.

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 NULL.

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 executed between the execution of glBegin and the corresponding execution of glEnd.

GLXBadContextState is also generated if the rendering context current to the calling thread has GL renderer state GLX_FEEDBACK or GLX_SELECT.

GLXBadCurrentWindow is generated if there are pending GL 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.