LCD is essentially a memory mapped array. Each element is addressed by row and column, so in effect it can also be visualised as a raster display. To draw a vector on such a display you have to calculate which row/column elements need to be illuminated.
With a vector display the hardware had a start and end X-Y positions defined for each vector. The spot was turned on by changing the potential at the CRT control grid and then X and Y were ramped to the end point before turning the spot off. It worked much like an analogue X-Y plotter. This was very efficient for simple cartoon like graphics , and also gave a display with considerably higher contrast and brightness than the alternative raster displays of the time. -------------------------------------------------- From: "leee" <l...@spatial.plus.com> Sent: Wednesday, March 03, 2010 1:56 PM To: "FlightGear developers discussions" <flightgear-devel@lists.sourceforge.net> Subject: Re: [Flightgear-devel] New GUI Font > On Tuesday 02 Mar 2010, HB-GRAL wrote: >> Melchior FRANZ schrieb: >> > * HB-GRAL -- Tuesday 02 March 2010: >> >> Melchior FRANZ schrieb: >> >>> Helvetica is the default font used in HUDs (e.g. in the F16). >> >>> While not perfect for that (there are MIL standards for >> >>> this), >> >> >> >> Do you mean in real HUDs? >> > >> > Real HUDs use a MIL standard font. Ours use Helvetica. I even >> > tuned that for the use in HUDs, as the prior version didn't >> > look good in tapes. I don't say that yours is worse, just that >> > it can't be swapped without checking. And a MIL spec compliant >> > font should be the ultimate goal, anyway. >> >> Yes, I see that I misunderstood your comment about f-16. >> >> As I started to work for a 'all-in-one FG-Font' I had the HUD in >> mind and also signage because the original and OFL-Allerta is >> exactly for this purpose (there are some equal requirements for >> fonts in a display and for signage I think). Now the real >> standard numbers like yours(?) in the sign textures are miles >> better then anywhere and this standard is also used in some real >> HUDs. I think now it is better to separate all this things and >> not to work for a 'all-in-one'. >> >> Thanks- Yves > > Does anyone know if raster displays are used in modern HUDs? The > early first generation huds were all vector displays, of course, > but Wikipedia says that second generation HUDs use an LCD screen to > modulate the light from an LED. However, it's still not clear to > me whether this counts as a raster display (although it does > suggest a raster mask). > > That all the HUD images I've ever seen, including modern ones, are > still monochrome suggests that they're still essentially vector > displays, for if the imagery is produced using an LCD then I'd > expect to see different colours on the HUD, instead of the > ubiquitous green (although red/orange has been used on some > automobiles). > > If anyone can find some high-res pictures of _real_ HUD displays > (and not ones from flight sims, as they're obviously going to be > produced via a raster display) it should be possible to see the > LCD 'dots' (unless they LCD screen uses a ridiculously high > resolution, which doesn't really chime with the requirements for > size and ruggedisation). > > Anyway, a vector type font should be used on older first generation > HUDs for authenticity. > > LeeE > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > Flightgear-devel mailing list > Flightgear-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/flightgear-devel ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
