*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->IRIX man pages -> stereo (7)              


STEREO(7)							     STEREO(7)

NAME    [Toc]    [Back]

     stereo - stereo viewing on	Silicon	Graphics systems

DESCRIPTION    [Toc]    [Back]

     All SGI graphics systems have one or more ports for connecting stereo
     viewing equipment to enable 3-D stereo presentation of computer graphics
     imagery.  The Stereo port provides	power for the external viewing
     equipment,	and provides a Stereo Field sync signal	to synchronize the
     external viewing equipment	to the time-multiplexed	stereo video.

     When the Stereo Sync signal is High, the system is	displaying the RightEye
 view; when it is low, the system is displaying	the Left-Eye view.
     External stereo viewing equipment uses this signal	to synchronize its
     time-multiplexing of the video into the viewer's left and right eyes,
     creating the illusion of a	stereoptic presentation	of the graphics
     images.  For more information on creating Left-Eye	and Right-Eye views,
     see the article, High Resolution Virtual Reality, by Michael Deering in
     ACM Computer Graphics, vol. 26, number 2, the 1992	SIGGRAPH proceedings,
     page 195.

     To	display	stereo images, a stereo-capable	software application must be
     running on	a stereo-capable graphics system, to which the appropriate
     external stereo viewing equipment has been	attached.  The system must be
     running a stereo-video format.  See xsetmon(1), setmon(1G)	and
     setmonitor(3G) for	details	on setting the system to stereo	video format.

     Three different kinds of stereo are supported on SGI equipment.  The
     first two methods use the stereo connection described above to
     synchronize external viewing equipment, such as the CrystalEyes stereo
     goggles.  The third method	is used	for head mounted displays.

     1.	 The most common is 1280x492 pixels per	left/right field, at 60
     field-pairs per second.  All Silicon Graphics workstation models support
     this kind of stereo.  This	method has been	called divided screen or split
     screen stereo in various documents, because the frame buffer is divided
     into 2 parts, one for each	eye.  Stereo applications render the left-eye
     view into the top half of the frame buffer, using lines 0-491.  The
     right-eye view is rendered	into the bottom	half of	the frame buffer using
     lines 532-1023 (on	all systems except O2, which uses lines	512-1003).
     The application must adjust the transformation matrix to correct for the
     fact that pixels are not square in	this format.  There are	two variations
     on	split screen stereo.  In the first, called old-style stereo, a single
     application takes over the	entire screen and is responsible for all
     rendering,	typically using	the older IRIS GL application program
     interface.	 This kind of stereo is	selected by giving the STR_RECT	option
     to	setmon.	 In the	second variation, which	uses the SGI Stereo X
     extension,	applications can render	stereo into a window on	a desktop that
     includes other windows.  The SGI Stereo X extension includes these
     functions:	XSGIStereoQueryExtension, XSGIStereoQueryVersion,
     XSGIQueryStereoMode, XSGISetStereoMode, and XSGISetStereoBuffer.  This
     kind of stereo is selected	by giving the STR_TOP or STR_BOT option	to
     setmon, or	by selecting "Top" or "Bottom" when prompted by	xsetmon	after

									Page 1

STEREO(7)							     STEREO(7)

     the user chooses a	split-screen stereo timing table. The windowing	system
     is	responsible for	putting	up menus, popups, etc. in both the top and
     bottom halves of the screen, in order to make stereo-in-a-window work.

     2.	 Another stereo	method,	Quadbuffer Stereo, dedicates separate frame
     buffers to	each eye, so it	uses four buffers when displaying double
     buffered stereo images.  This method renders and displays square pixels,
     and does not require the windowing	system to render its widgets in	two
     places. Stereo applications render	the left-eye and right-eye views to
     the same pixel locations in the screen or window, but select either the
     left buffer or right buffer when rendering	views for the left or right
     eye, respectively.	 This method allows several different display
     resolutions, and has the advantage	of allowing the	software application
     to	render to a square-pixel space.	 This results in higher	image quality,
     especially	for anti-aliased rendering.  This method is typically selected
     by	using setmon or	xsetmon	to load, for example, the 1024x768_96s timing

     3.	 The third way of doing	stereo is with the Multi-channel option	(MCO),
     which dedicates a video channel per eye.  This method is popular for
     virtual reality helmets, but is beyond the	scope of this document.	 No
     Stereo Sync is needed for this kind of stereo.  The two video channels
     must be genlocked together.  See setmon(1G) and setmonitor(3G) for
     details on	enabling the genlock function.

     In	some multi-screen stereo applications it is desirable to genlock the
     stereo screens together.  Care must be taken to ensure that right-eye
     views are locked together.	 For some older	stereo formats,	this may
     require several tries.  See setmon(1G) for	details	on enabling the
     genlock function.

									Page 2

STEREO(7)							     STEREO(7)


     There are four different types of stereo ports found on various Silicon
     Graphics systems.

     The DIN-8 powered serial port connectors, which are found on the Onyx and
     Crimson models, provide Stereo Sync in addition to	serial communication
     signals for other types of	peripherals.  The serial signals are not used
     by	external stereo	viewing	equipment, but the pin-out description of all
     signals on	the DIN-8 is provided here for completeness.

     In	order to support peripherals which draw	power from the host system,
     the Challenge and Onyx systems provide two	powered-peripheral serial
     ports.  These ports have a	DIN-8 connector.  These	ports share the	tty2
     and tty3 signal lines with	the standard DB-9 connectors; if the DB-9
     connector for tty2	is already in use, you cannot use the powered
     peripheral	connector for tty2.  Similarly,	if tty3's DB-9 connector is
     connected to a peripheral,	the powered peripheral port connected to the
     tty3 signal lines cannot also be used.  The Stereo	SYNC signal is brought
     out in parallel to	both ports. The	powered	peripheral ports have the
     following pin assignments:

				     /	 2   \
				    /4	     5\
				   /	       \
				  ( 1	 8    3	)
				   \	       /
				    \ 6	    7 /

		     |Pin | Name | Description		      |
		     | 1  | DTR	 | Data	Terminal Ready	      |
		     | 2  | CTS	 | Clear To Send	      |
		     | 3  | SYNC | Stereo Sync/GND (jumpered) |
		     | 4  | RD	 | Receive Data		      |
		     | 5  | TD	 | Transmit Data	      |
		     | 6  | SG	 | Signal Ground	      |
		     | 7  | GND	 | Ground point		      |

									Page 3

STEREO(7)							     STEREO(7)

     The Onyx and Crimson also provide Stereo Sync and Stereo Power as part of
     the 13W3 RGB video	port.  Note: the Elan and Indy products	do NOT have
     stereo support in its 13W3	port.  This connector has the following	pin

			  \ A1	 1  2  3  4  5	 A2  A3	/
			   \   6  7  8	9  10	       /

	  |Pin | Name	    | Description				|
	  |A1  | RED	    | Analog Red signal				|
	  |A2  | GRN	    | Analog Green signal + optional video sync	|
	  |A3  | BLU	    | Analog Blue signal			|
	  | 1  | N/C	    |						|
	  | 2  | MONTYPE_0  | Monitor ID bit 0				|
	  | 3  | N/C	    |						|
	  | 4  | STEREO	    | Stereo Sync signal			|
	  | 5  | STEREO_PWR | Stereo Power, +10V			|
	  | 6  | MONTYPE_1  | Monitor ID bit 1				|
	  | 7  | MONTYPE_2  | Monitor ID bit 2				|
	  | 8  | GND	    |						|
	  | 9  | GND	    |						|

									Page 4

STEREO(7)							     STEREO(7)

     Indy, Indigo, Indigo2 (Elan, Extreme, XS, or XZ), and O2 models use a
     micro-DIN connector for the following Stereo port:

				     /	 3   \
				    /	      \
				   / 2	     1 \
				  (		)
				   \	 #     /
				    \	      /

			  |Pin | Name	| Description	|
			  | 1  | PWR	| +12V		|
			  | 2  | GND	| Signal Ground	|

     Indigo2 and Octane	models with IMPACT graphics use	a DB9 connector	for
     stereo.  This connector has the following pin assignments:

				\  5  4	 3  2  1  /
				 \   9	8  7  6	 /

			  |Pin | Name	| Description	|
			  | 1  | STEREO	| Stereo Sync	|
			  | 6  | GND	| Signal Ground	|
			  | 7  | GND	| Signal Ground	|

SEE ALSO    [Toc]    [Back]

     xsetmon(1), setmon(1G), setmonitor(3G)

									PPPPaaaaggggeeee 5555
[ Back ]
 Similar pages
Name OS Title
sgihelp IRIX The Silicon Graphics Help Viewer
syssgi IRIX Silicon Graphics Inc. system call
alIntro IRIX Introduction to the Silicon Graphics Audio Library (AL)
t3270 IRIX Silicon Graphics 3270 interface card
CDintro IRIX Introduction to the Silicon Graphics CD Audio Library (CD)
DTintro IRIX Introduction to the Silicon Graphics DAT Audio Library (DT)
dmColor IRIX The Silicon Graphics Color Space Library (CSL)
rgb IRIX Silicon Graphics rgb image file format
mdIntro IRIX Introduction to the Silicon Graphics MIDI Library (libmd)
Xsgi IRIX X Window System server for Silicon Graphics workstations.
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service