glXCreateGLXVideoSourceSGIX(3G)				OpenGL Reference - GLX

NAME    [Toc]    [Back]

     glXCreateGLXVideoSourceSGIX - create a GLX	handle for a video input
     stream

C SPECIFICATION    [Toc]    [Back]

     GLXVideoSourceSGIX	glXCreateGLXVideoSourceSGIX( Display *dpy,
						     int screen,
						     VLServer svr,
						     VLPath path,
						     int nodeClass,
						     VLNode node )

PARAMETERS    [Toc]    [Back]

     dpy	A connection to	an X server.

     screen	The X screen number of the screen on which the GLX video
		source should be created.

     svr	A connection to	a Video	Library	video server.

     path	A Video	Library	video transfer path.

     nodeClass	The class of the VLNode	specified by node.

     node	A VLNode which must be a VL_DRAIN node on the video transfer
		path path.

DESCRIPTION    [Toc]    [Back]

     glXCreateGLXVideoSourceSGIX creates a GLX video source.  Once created, it
     may be used as the	read parameter on a call to glXMakeCurrentReadSGI.
     Thereafter	the GL can transfer video data to the framebuffer using
     glCopyPixels or to	texture	memory using glCopyTexSubImage2DEXT.

     The configuration of a GLX	video source is	static,	and is fixed at	the
     time that it is created.  If any of the controls which affect the
     transfer of video data are	changed	on the video transfer path for which a
     particular	GLX video source was created, the GLX video source should be
     destroyed and a new one created.  Otherwise the data read from the	source
     will be undefined.

     To	destroy	a GLX video source when	it is no longer	needed,	call
     glXDestroyGLXVideoSourceSGIX.

NOTES    [Toc]    [Back]

     glXCreateGLXVideoSourceSGIX is part of the	SGIX_video_source extension.
     See glXintro for more information about using GLX extensions.

     See glCopyPixels, glCopyTexImage2DEXT, and	glCopyTexSubImage2DEXT for
     information about using GL_INTERLACE_SGIX to assemble textures or frame
     buffer images from	the fields of an interlaced video format.



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glXCreateGLXVideoSourceSGIX(3G)				OpenGL Reference - GLX



     See VLintro(3dm) for an introduction to the Video Library (VL).

     A GLX video source	may be used only with GLX rendering contexts created
     on	the same screen.

ERRORS    [Toc]    [Back]

     BadAlloc is generated if glXCreateGLXVideoSourceSGIX is unable to
     allocate the resources needed to create a GLX video source.


MACHINE	DEPENDENCIES
     On	RealityEngine, RealityEngine2, and VTX systems,	when a video source is
     the read drawable (see glXMakeCurrentReadSGI), then:

	  1.  glCopyPixels cannot be used when any of the RGBA scale factors
	      is not 1,	when any of the	RGBA bias terms	is not 0, or when any
	      of texturing, alpha or depth testing, pixel mapping,
	      multisampling, convolution, histogram, or	minmax is enabled.  A
	      GL_INVALID_OPERATION error will result if	any of these
	      conditions is true when glCopyPixels is executed.

	  2.  glCopyTexSubImage2D and glCopyTexSubImage2DEXT can only be
	      executed when the	X offset and Y offset are 0 and	the subimage
	      width is 768.  A GL_INVALID_VALUE	error is generated otherwise.

	  3.  glCopyTexImage2D and glCopyTexImage2DEXT cannot be used.	A
	      GL_INVALID_OPERATION error is generated when it is executed.

SEE ALSO    [Toc]    [Back]

     glXDestroyGLXVideoSourceSGIX, glXMakeCurrentReadSGI, VLintro(3dm)


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