Angus Dorbie (dorbie++at++sgi.com)
Wed, 19 Aug 1998 11:30:51 -0700
The two keyboard slots can be used when you have more than one pipe.
> Secondly, /usr/gfx/gfxinfo says: Managed (":0.0") 1280x1024
> Does this mean I can have maximum of this resolution. I tried with
> video format compiler, it says can't manage xxx area. Does this depend
> on video ram I have. It is 4MB external BEF ram, 32bit path. How can I
> upgrade it.
On infinite Reality with RM7 or RM9 boards you have 80 MB of
framebuffer memory, Reality uses RM8 boards and has 40 MB.
Each RM buys you lots of framebuffer real estate for your
desktop managed area from which you can take 2 or 8 video
channels depending on your Display Generator board.
1 RM should be enough for 2*1280x1024 with small pixel depth.
Reality supports extra small depth so you can still muster
this kind of real estate on reality.
Use /usr/gfx/ircombine and the "edit globals" dialog (press
button on lower right) to edit the managed area size. Then
position video formats, press a channel along the top to
browse your video options. You'll have to save to eeprom and
restart the X server to change the managed area size. Use the
"Vulcan Death Grip" to easily kill & restart the server on
any SGI that's:
[left shift] + {left ctrl] + [f12] + [numeric keypad /]
Don't try this unless you want to kill the server, you'll
have to log in again and everything relying on an X connection
will die.
>
> The picture on Onyx2 looks slightly dull compaired to O2s, no matter
> what contrast-brightness you change. Is gamma of the system is wrong.
The gamma of the system is adjustable, but it's probably close to the
O2.
> Currently it is 1.7, same as all O2s. The /usr/sbin/gamma manual says
> it is normaly 2.4 How do I find out gamma of monitor, gamcal is
> useless.
gamcal is not useless, adjust your gamma until the stripe regions
average luminance is equal to the solid gray luminance, you may have
to defocus your eyes to see this. When this is the case on _both_
the O2 and the Infinite Reality the you will have 1/(monitor gamma)
tables loaded on each machine which is what you need for correct
linear response. You use the gamma command for this and actually
type the monitor gamma so "gamma 2.4" on the command line will
probably be approximately what you need depending on ambient
illumination and if you have set your black level correctly.
It is likely that you have your gamma on the O2 lower than you should,
the typical out of the box gamma on SGI is 1.7 and that is too low.
For anti-aliasing quality etc. the gamma on should be higher, which
will probably make some colors look less saturated. All things being
equal you should be able to build a suitable database. Unless you
really know what you are doing w.r.t. gamma don't scan your textures
on a PC because you are likely to get ~1/2.5 gamma corrected images
which will then have the wrong correction built in and will look
too bright and unsaturated on any system with correct gamma set,
in other words you textures will get double gamma corrected.
Performer does NOT have and built in gamma to compensate for this low
number despite shoddy reports to the contrary.
The correct approach is to set system gamma to 2.2 or build some
additional gamma correction into your database/application (which
is an approximation but may be required to avoid perceptible
quantizing on night visuals).
Cheers,Angus.
-- "Only the mediocre are always at their best." -- Jean GiraudouxFor advanced 3D graphics Performer + OpenGL based examples and tutors: http://www.dorbie.com/
This archive was generated by hypermail 2.0b2 on Wed Aug 19 1998 - 11:30:55 PDT