wave@media-lab.MEDIA.MIT.EDU (Michael B. Johnson) (04/04/91)
I was having a discussion with a friend of mine who builds head mounted displays (Private Eye). He was showing me the chip he (and another guy) had designed and built to allow the Private Eye to look like a CGA display so that people could just plug it into their PC. Pointing to the size of the ASIC chip, he pointed out that there was a reasonable amount of silicon devoted to transposing the data from CGA format to the Private Eye's on-the-side-format (similar to transposing data on the CM-2). We talked about what it would take to put the Private Eye into another machine, namely a NeXT machine. Since you can also address the Private as a 720 X 2?? display, it seemed feasible that if you could convince the Window Server to render to a bitmap of that resolution, you'd then have to transpose the data and get it to the Private Eye. We came on the idea that it might be possible to use the DSP to transpose the data and you could then shove it out the DSP port. So I guess I have two questions: Does anybody have any ideas where to look about getting the Window Server to render to a bitmap of a particular resolution? I assume this is very similar to the problem of writing a driver for a printer. The other question involves DSP use: have people done anything like this, i.e. using the DSP to transpose a stream of data moving through it? I assume this isn't that strange a notion of using a DSP chip... Any pointers would be appreciated; e-mail is probably a better idea than posting - there's too much traffic here already. If there is sufficient interest in the answers, I'll post a summary of the useful data I get. -- --> Michael B. Johnson --> MIT Media Lab -- Computer Graphics & Animation Group --> (617) 253-0663 -- wave@media-lab.media.mit.edu
mdixon@parc.xerox.com (Mike Dixon) (04/04/91)
Does anybody have any ideas where to look about getting the Window
Server to render to a bitmap of a particular resolution?
some variant of this question seems to turn up quite regularly; the
answer is that it's trivial. postscript doesn't actually care what
resolution your device is -- it just generates bitmaps based on the
current transformation. tell the window server you want to render
to a machportdevice, and it gives you an initial transformation of
1 pixel per postscript point; if you want something else, just use
the 'scale' operator.
--
.mike.eps@toaster.SFSU.EDU (Eric P. Scott) (04/05/91)
In article <mdixon.670723893@thelonius> mdixon@parc.xerox.com (Mike Dixon) writes: >some variant of this question seems to turn up quite regularly; the >answer is that it's trivial. postscript doesn't actually care what >resolution your device is -- it just generates bitmaps based on the >current transformation. tell the window server you want to render >to a machportdevice, Unfortunately, that's really not the correct answer here; machportdevice is for implementing things that look like printers (e.g. printers and FAX machines)--things where one uses showpage/copypage operators to render completed pages. Instead, the original poster needs to look into adding a secondary display screen; this means a driver in /usr/lib/NextStep/Displays/ and appropriate NetInfo "screens" entries. Look at how the NeXTdimension support works in 2.1. > and it gives you an initial transformation of >1 pixel per postscript point; if you want something else, just use >the 'scale' operator. No, it gives you the initial transformation you specify as a mandatory argument to machportdevice. See Chapter 4 of the NextStep Reference. -=EPS=-