[comp.sys.sgi] Overlay planes

tjh@bu-cs.BU.EDU (Timothy Hall) (08/16/89)

Real work question:

I am planning on porting a paint package to our 240 soon.  The package wants
8 bitplanes and the Iris 4sight manual tells me the max overlay planes I
can get is 4.  (I don't need the window manager)  Now somewhere along the
line I thought I heard the 240 has 96 bitplanes - 64 bits image buffer -
24 bit z-buffer and 8 bits of overlay.  So is my memory fading?  If not how
do I get all 8 overlay planes?

Real play question:

So how does one get the version of flight with the Klingon ship that blows
craters in the Earth and also has an x-wing fighter?  I got the source demo
tape from Monica Schultz (?) and requested the above but only got normal every
day flight that doesn't let you fly east or west.  (Makes it damn hard to land
on the short taxi way!)  Are there any other fun programs out there besides
the standard SGI demos?

-Tim Hall
Boston University Computer Graphics Lab
tjh@bu-pub.bu.edu

thant@horus.sgi.com (Thant Tessman) (08/16/89)

In article <36536@bu-cs.BU.EDU>, tjh@bu-cs.BU.EDU (Timothy Hall) writes:
> Real work question:
> 
> I am planning on porting a paint package to our 240 soon.  The package wants
> 8 bitplanes and the Iris 4sight manual tells me the max overlay planes I
> can get is 4.  (I don't need the window manager)  Now somewhere along the
> line I thought I heard the 240 has 96 bitplanes - 64 bits image buffer -
> 24 bit z-buffer and 8 bits of overlay.  So is my memory fading?  If not how
> do I get all 8 overlay planes?
> 
[the question I don't know how to answer deleted]
> 
> -Tim Hall
> Boston University Computer Graphics Lab
> tjh@bu-pub.bu.edu


Four bits are for overlay and four are for window I.D.  That's how the 
machine does arbitrarily shaped and/or overlaping windows in different
modes that can be independently swapped, all without any performance hit.

If you talk about what you need the 8 overlays for, somebody may have a
a better/workable solution.  (What machine had 24 bits of color AND 8 bits
of overlay?)

thant@sgi.com