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

NAME    [Toc]    [Back]

     glXChannelRectSGIX	- specify area of frame	buffer to resize to video
     resolution

C SPECIFICATION    [Toc]    [Back]

     int glXChannelRectSGIX( Display *dpy,
			     int screen,
			     int channel,
			     int x,
			     int y,
			     int w,
			     int h )

PARAMETERS    [Toc]    [Back]

     dpy      Specifies	the connection to the X	server.

     screen   Specifies	the screen of the X server.

     channel  Specifies	the video channel number.

     x,	y, w, h
	      The origin and size of the area of the window that will be
	      converted	to the output resolution of the	video channel.	(x,y)
	      is relative to the bottom	left corner of channel specified by
	      the current video	combination.

DESCRIPTION    [Toc]    [Back]

     glXChannelRectSGIX	sets the rectangular area of the frame buffer that
     will be resized to	match the output resolution of channel.	The specified
     frame buffer area is not resized until glXSwapBuffers is called for the
     window that is bound to channel. Call glXBindChannelToWindowSGIX to bind
     a window to a channel.

     Note that the origin and size of the specified area must conform to the
     precision constraints returned by glXQueryChannelDeltasSGIX.

     glXChannelRectSGIX	returns	True if	it succeeds. If	it fails, False	is
     returned and the frame buffer area	remains	unchanged.

EXAMPLE    [Toc]    [Back]

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



	  XSGIvcChannelInfo   *pChanInfo = NULL;

	   ... open display and	screen ...


	  XSGIvcQueryChannelInfo( display, screen, channel, &pChanInfo );

	  X = pChanInfo->source.x;
	  Y = pChanInfo->source.y;
	  W = pChanInfo->source.width;
	  H = pChanInfo->source.height;

	   ... open an X window	(preferably with no borders so will not	get ...
	   ... moved by	window manager)	at location X,Y,W,H (X coord system) ...

	  glXBindChannelToWindowSGIX( display,screen,channel,window );

	  glXQueryChannelDeltasSGIX( display,screen,channel, &dx,&dy,&dw,&dh );

	  while( ... )
	  {
	      ... determine area(width,height) that will be drawn ...
		  ... based on performance requirements.  Make ...
	      ... area smaller if application is fill limited ...

	      w	=  width - ( width % dw	);
	      h	=  height - ( height % dh );

	      glViewport( 0,0,w,h );

	      glXChannelRectSGIX( display,screen,channel, 0,0,w,h );

	      ... draw scene ...

	      glXSwapBuffers( display,window );
	  }

NOTES    [Toc]    [Back]

     glXChannelRectSGIX	is part	of the SGIX_video_resize extension.

ERRORS    [Toc]    [Back]

     glXChannelRectSGIX	returns	False if the specified area does not conform
     to	the precision constraints returned by glXQueryChannelDeltasSGIX.

     glXChannelRectSGIX	returns	False if channel is not	bound to a window.

     glXChannelRectSGIX	returns	False if channel is not	a valid	independent
     channel.




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



MACHINE	DEPENDENCIES
     The SGIX_video_resize extension is	supported only on InfiniteReality
     systems.

SEE ALSO    [Toc]    [Back]

     glXBindChannelToWindowSGIX, glXQueryChannelRect,
     glXQueryChannelDeltasSGIX,	glXSwapBuffers


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