[HN Gopher] FantasyLand on VGA
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FantasyLand on VGA
Author : kencausey
Score : 42 points
Date : 2022-04-04 12:46 UTC (10 hours ago)
(HTM) web link (www.os2museum.com)
(TXT) w3m dump (www.os2museum.com)
| h2odragon wrote:
| EGA cards were truly funky beasts. There was a "64 color" stunt
| where you could switch the 16 color palette fast enough to have
| up to 4 different palettes visible on screen at once.
|
| There were fringe flavors of compatibles, with extra capabilites.
| 400 scanline modes that enabled 43 and 50 lines text modes hover
| in my memory.
| shdon wrote:
| 400 scanline modes gave us 50 lines of text by virtue of
| loading the 8x8 pixel font (400/8=50). There was no
| incompatible trickery going on for 43 line mode. That was just
| the 8x8 pixel font at the standard 350 scanlines (350/8=43.75).
|
| The palette was weird because changing palette entries away
| from the standard 16 CGA colours was impossible in 200 scanline
| modes. It was only possible in 350 scanline mode (and also on
| VGA, but I digress). That's because the EGA could connect (and
| often would be connected) to CGA monitors and adjusted the
| pinout of the connector accordingly. This meant just 1 bit per
| colour channel and 1 intensity bit. The full EGA palette
| required 2 bits per colour channel and could only be used on
| actual EGA monitors. The way IBM ensured that was limiting
| palette changes to the 640x350 mode.
| bitwize wrote:
| Pfff... getting more colors on screen than you have palette
| entries is not a stunt at all... not on a thoughtfully designed
| system with raster interrupts. On the Amiga you could even
| program the copper to do this work for you, freeing up the CPU
| for other tasks.
| TonyTrapp wrote:
| How about 1024 colors on CGA?
| https://int10h.org/blog/2015/04/cga-in-1024-colors-new-mode-...
| djmips wrote:
| This reminds me that, back in the eighties, a friend of mine made
| a super cool EGA BBS terminal program with split screens and
| smooth scrolling - but it also used the vertical retrace
| interrupts. It's a shame there wasn't more compatibility around a
| lot of this on PC since it would have enabled some very cool
| software that everyone could use.
| glhaynes wrote:
| YouTube video of this program. Not sure what hardware (or
| emulation) it's running on but it doesn't appear buggy.
| https://www.youtube.com/watch?v=RRnHzt7X0OE
| ttul wrote:
| Id Software managed to get smooth scrolling working on EGA - a
| mind blowing achievement at that time.
|
| https://en.wikipedia.org/wiki/Adaptive_tile_refresh
| joakleaf wrote:
| id Software and Carmack often gets credit for this, but I
| remember seeing a number of games already using smooth-
| scrolling in EGA before. Zanygolf from 1988 and Rick Dangerous
| 1989 comes to mind (albeit vertical scrolling). Harvard
| Graphics 2.3 (from 1990) could also use smooth-scrolling in EGA
| (640x350) when running presentations.
|
| I am pretty sure Lemmings (early 1991) also used the horizontal
| smooth-scrolling capabilities of EGA/VGA.
|
| For reference, id software's Commander Keen is from late 1990.
|
| I remember trying to work with the smooth scrolling registers
| on VGA (256 color mode) in 1991/1992 myself. The registers were
| described in the EGA/VGA programmers reference (1988), and I
| suspect the author of that book must have known that the
| hardware was capable of this. Unfortunately, smooth-scrolling
| required using a combination of several registers, so as far I
| remember, the documentation of this was scattered all over the
| book under the different registers, and wasn't really easily
| approachable for the reader.
|
| Of course, the techniques behind smooth-scrolling and page-
| swapping for VGA (e.g. mode-X) were really popularized when
| Michael Abrash published an article about it in 1991 in Dr.
| Dobbs.
|
| Gaming on the PC from '87 to 1992 would probably have been very
| different, if IBM had just described smooth-scrolling and other
| hidden gems of the EGA/VGA cards in more detail.
| JohnBooty wrote:
| That's super interesting. How did Harvard Graphics use smooth
| scrolling? I see that it smoothly animated some screen
| elements, but not a whole screen-filling background ala
| Commander Keen.
|
| https://youtu.be/wwqm0zOivUU?t=1007
|
| I'm not familiar with Harvard Graphics _or_ EGA graphics
| details, so, might be a dumb question.
|
| As an aside, it's eternally hilarious to me that there were
| so many capabilities in the EGA/VGA chipsets that were
| "hidden." IBM clearly spent a lot of engineering time (and
| die space!) implementing them... and then it still took ages
| for them to be "discovered."
|
| Did IBM just neglect to promote them to developers? Or did
| they intentionally sort of bury those features so as not to
| be seen as having built a "game machine?" Always curious.
| joakleaf wrote:
| In Harvard Graphics, I am pretty sure it was used with the
| "Scroll" transition in slide shows. That option is visible
| in at 15.34 in your video for the "Euromap.cht". As I
| remember, it only ran smoothly (i.e. used the smooth
| scrolling registers) in 640x350.
| JohnBooty wrote:
| Ah. Thanks! Interesting!
| syntheweave wrote:
| If you look at the software that was being put out in the
| mid-80s, there's a clear picture of "IBM being IBM" in that
| it had designed some graphics APIs that worked according to
| their corporate view of what applications needed[0]...and
| then the market ignored it, and programmed the hardware
| registers directly. And many of the features make sense in
| this light as being something designed to the APIs they had
| in mind, but then otherwise not given much attention or
| support.
|
| A critical part of Microsoft's rise in this era was in
| grabbing up pieces of market share that the competition had
| overlooked, and their graphics story with Windows
| definitely enters into this. GDI didn't have conflicts of
| interest from being both a hardware and software maker, and
| so it could focus just on compatibility - a classic example
| of "worse is better".
|
| [0] https://en.m.wikipedia.org/wiki/Graphical_Data_Display_
| Manag...
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