glXMakeContextCurrent(3G)   OpenGL Reference - GLX   glXMakeContextCurrent(3G)

NAME    [Toc]    [Back]

     glXMakeContextCurrent - attach a GLX context to a GLX drawable

C SPECIFICATION    [Toc]    [Back]

     Bool glXMakeContextCurrent( Display *dpy,
				 GLXDrawable draw,
				 GLXDrawable read,
				 GLXContext gc )

PARAMETERS    [Toc]    [Back]

     dpy   Specifies the connection to the X server.

     draw  Specifies a GLX drawable that to render into.  Must be an XID
	   representing	a GLXWindow, GLXPixmap,	or GLXPbuffer.

     read  Specifies a GLX drawable that to read from.	Must be	an XID
	   representing	a GLXWindow, GLXPixmap,	or GLXPbuffer.

     gc	   Specifies the GLX context to	be bound to read and gc.

DESCRIPTION    [Toc]    [Back]

     glXMakeContextCurrent binds gc to the current rendering thread and	to the
     draw and read GLX drawables. draw and read	may be the same.

     draw is used for all OpenGL operations except:

       Any pixel data that are read based on the value of GL_READ_BUFFER.
       Note that accumulation operations use the value of GL_READ_BUFFER, but
       are not allowed unless draw is identical	to read.

       Any depth values	that are retrieved by glReadPixels or glCopyPixels.

       Any stencil values that are retrieved by	glReadPixels or	glCopyPixels.

     Frame buffer values are taken from	draw.

     If	the current rendering thread has a current rendering context, that
     context is	flushed	and replaced by	gc.

     The first time that gc is made current, the viewport and scissor
     dimensions	are set	to the size of the draw	drawable.  The viewport	and
     scissor are not modified when gc is subsequently made current.

     To	release	the current context without assigning a	new one, call
     glXMakeContextCurrent with	draw and read set to None and gc set to	NULL.

     glXMakeContextCurrent returns True	if it is successful, False otherwise.
     If	False is returned, the previously current rendering context and
     drawable (if any) remain unchanged.




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glXMakeContextCurrent(3G)   OpenGL Reference - GLX   glXMakeContextCurrent(3G)

NOTES    [Toc]    [Back]

     glXMakeContextCurrent is available	only if	the GLX	version	is 1.3 or
     greater.

     If	the GLX	version	is 1.1 or 1.0, the GL version must be 1.0.  If the GLX
     version is	1.2, then the GL version must be 1.1.  If the GLX version is
     1.3, then the GL version must be 1.2.

ERRORS    [Toc]    [Back]

     BadMatch is generated if draw and read are	not compatible.

     BadAccess is generated if gc is current to	some other thread.

     GLXContextState is	generated if there is a	current	rendering context and
     its render	mode is	either GL_FEEDBACK or GL_SELECT.

     GLXBadContext is generated	if gc is not a valid GLX rendering context.

     GLXBadDrawable is generated if draw or read is not	a valid	GLX drawable.

     GLXBadWindow is generated if the underlying X window for either draw or
     read is no	longer valid.

     GLXBadCurrentDrawable is generated	if the previous	context	of the calling
     thread has	unflushed commands, and	the previous drawable is no longer
     valid.

     BadAlloc is generated if the X server does	not have enough	resources to
     allocate the buffers.

     BadMatch is generated if:

       draw and	read cannot fit	into frame buffer memory simultaneously.

       draw or read is a GLXPixmap and gc is a direct rendering	context.

       draw or read is a GLXPixmap and gc was previously bound to a GLXWindow
       or GLXPbuffer.

       draw or read is a GLXWindow or GLXPbuffer and gc	was previously bound
       to a GLXPixmap.

SEE ALSO    [Toc]    [Back]

     glXCreateNewContext, glXCreateWindow, glXCreatePixmap, glXCreatePbuffer,
     glXDestroyContext,	glXGetCurrentContext, glXGetCurrentDisplay,
     glXGetCurrentDrawable, glXGetCurrentReadDrawable, glXMakeCurrent


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