glXCreateGLXVideoSourceSGIX(3G)

NAME
     glXCreateGLXVideoSourceSGIX - create a GLX handle for a video input
     stream


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


PARAMETERS
     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
     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
     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.
     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
     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
     glXDestroyGLXVideoSourceSGIX, glXMakeCurrentReadSGI, VLintro(3dm)