One of the most substantial benefits to the 160x200 16-color mode is that it uses half the video memory of the 320x200 16-color mode (16KB vs. 32KB). The CPU needs only send half as much data to the video memory, improving performance on any machine.
One drawback with the 160x200 16-color mode is that you can only uses 20-columns of text at the standard 8x8 pixel IBM character set. In this case, developers typically chose two options. First, they could use their own character set which would fit into a smaller pixel matrix. Maniac Mansion is an example of this option, it uses 4x8 characters for the Tandy mode and the standard 8x8 characters for CGA, MCGA, EGA or VGA modes. Second, they could use the 320x200 16-color mode, which is what King's Quest and its sequels use. In King's Quest, the pixels for the graphics display are doubled, improving performance to a good extent but not as much as if the true 160x200 mode was used.
Another benefit, which is under-appreciated these days, is that games using this mode look very good on a composite monitor. The IBM PCjr. and the early Tandy 1000s (1000/A/HD/EX/HX/SX/TX) have a composite video output jack. In a 320x200 mode, these computers show artifact colors that are markedly different from an IBM CGA card.
But in a 160x200 16-color mode, their composite colors correspond to their RGB colors quite well. This is because in this mode, the pixel clock is the same as the NTSC color burst frequency, 3.58MHz. Because the pixel clock is aligned with the color clock, the TV's color decoding circuitry can keep pace with the color changes being sent to it. Even in a psuedo-160x200 game like King's Quest, the doubling of the pixels makes the graphics look as they should, color-wise.
By contrast, the pixel clock in a 320 pixel mode is 7.16MHz and 14.318MHz in a 640 pixel mode. In those resolutions, the color decoding circuitry cannot keep up, leading to artifact colors. The timing of the PCjr. and Tandy video controller chips is "off" compared to the IBM PC CGA, leading to different artifact colors. The 320x200 16 color mode does not look good on a composite monitor, the artifacting becomes ugly at this point, especially when it comes to dithering.
The final benefit to the 160x200 mode is that the end result looks acceptable on a video capture device. Capturing 320x200 or 640x200 graphics from a CGA card, PCjr., Tandy or EGA card that gives a good representation of RGB color is much, much more difficult. First, you need a board that will convert the digital RGB signal to an analog RGB signal and preferably keeps color 6 brown, not dark yellow. (From the composite video output, color 6 will look closer to dark yellow than to brown.) Second, you will need a hardware device that can capture 15kHz RGB. They do exist, but most people would probably use a scan-line doubler and send it to a VGA capture device.
You may think that only a handful of games used a 160x200 mode, but you would be surprised. Here is a list of forty nine games that primarily use a 160x200 16-color mode for their graphics when run on a PCjr. or a Tandy 1000 :
| Black Cauldron, The |
| Boulder Dash |
| Boulder Dash II: Rockford's Revenge |
| Bruce Lee |
| California Games |
| Demon Attack |
| Donald Duck's Playground |
| F-15 Strike Eagle |
| Ghostbusters |
| Gold Rush! |
| Indianapolis 500 |
| Jumpman |
| King's Quest I: Quest for the Crown |
| King's Quest II: Romancing the Throne |
| King's Quest III: To Heir is Human |
| King's Quest IV: The Perils of Rosella |
| Leisure Suit Larry in the Land of the Lounge Lizards |
| Lost Tomb |
| Manhunter 2: San Francisco |
| Manhunter: New York |
| Maniac Mansion |
| Mickey's Space Adventure |
| Microsoft Flight Simulator (v2.0) |
| Microsurgeon |
| Mixed-Up Mother Goose |
| Mouser |
| Murder on the Zinderneuf |
| Ninja |
| Dr. J and Larry Bird go One-on-One |
| Pitfall II: Lost Caverns |
| Pitstop II |
| Police Quest: In Pursuit of the Death Angel |
| Rasterscan |
| River Raid |
| ScubaVenture |
| Sea Speller |
| Silent Service |
| Slugger, The |
| Space Quest I: The Sarien Encounter |
| Space Quest II: Vohaul's Revenge |
| Starflight |
| Storm |
| Super Bowl Sunday |
| The World's Greatest Baseball Game |
| Touchdown Football |
| Troll's Tale |
| Winnie the Pooh in the Hundred Acre Wood |
| Wizard and the Princess, The |
| Zak McKracken and the Alien Mindbenders |
are there any games that use 640 200 16?
ReplyDeletehow does this compare with apple iigs and commodore 64 coco3?
also can u blog about tandy color computer 3?
google locked me out but im a regular here i owned a tandy 1000 and my neighbors had color computer and c64 and iigs
Silpheed uses 640x200x16c:
Deletehttps://www.mobygames.com/game/silpheed
Planet X3 supports the Tandy Hi-res mode that later model 1000s have. I assume that's what you're referring to
DeleteMonkey Island 2 used 640x200x16 when run in EGA mode. Unlike EGA 640x350, which allows selection of 16 colors from a palette of 64, 640x200 mode is backward compatible with CGA monitors, so it's stuck with the typical 16 color CGA/EGA palette we all know. The benefit in Monkey Island 2 is that the 320x200x256 pixel could be divided into a left and right side, so that 2 colors could be used to dither in order to approximate one of 256 colors. In my opinion, this was great in theory, but not so hot in practice.
DeleteSierra's ports of Japanese home computer games from Game Arts and Falcom use 640x200x16, as does Koei's ports of their turn based strategy games to DOS like Nobunaga's Ambition and Romance of the Three Kingdoms.
ReplyDeleteMost C64 games use a 160x200 mode, but the colors are a bit different and you cannot put colors wherever you like, which prevented ports of the AGI games to that system. The Sierra AGI games use an effective 140x192 graphics mode with an Apple IIe/IIc and a 160x200 mode with the IIgs. The IIgs, Amiga and ST look pretty much like the PCjr/Tandy/EGA/MCGA/VGA adapters.
If someone sends me a Tandy CoCo 3, I would be happy to write about it. I do not write about computers or consoles I can only fully experience by way of emulation.
the 160x200 resolution was usefull to directly port graphics between different 8bit systems.
ReplyDeleteAppleII, Tandy/PCjr, Amstrad CPC, C64, I guess even Atari8bit computers had their most colourfull video modes using this resolution.
As computer market could need many different version on different uncompatible systems, any portability could mean less paid hourswork from specialised coders or graphic artists.
Many Amiga games were basically Atari ST games in 16 colours only, many Amstrad CPC games were ZX spectrum ports with jsut less colours, some games released on many platforms would get huge bits of graphics straightly ported with sometimes only insulting calculated palette conversions.
Hello again,
ReplyDeleteI have a question about your Tandy/PCjr 16 color blog. I found this fellow in Australia through ebay. He offered to take the IBM DOS Troll's Tale download, and load it onto a 5.25 floppy disk for me, so that I may play the game on my PCjr hardware. For the moment, I haven't received it yet, but I was wondering something. I ran the Troll's Tale game through Dosbox. In Dosbox options you can change the machine that it emulates. Whenever I choose "machine=" Tandy, or cga, or vga, or ega, it always showed me the Troll's Tale game in that 4 color palette. However, when I chose "machine=pcjr" I got the full enhanced 16 mode. My question is, when I run this person's disk through an "actual" pcjr, do you think I might get the same result?
I believe that Troll's Tale is a PCjr. exclusive 16-color game. It was released before the Tandy 1000s were released, so it only tries to detect a PCjr. There is a particular byte in the BIOS which, depending on its value, identifies a PC or a PCjr. PCs and Tandys identify themselves as PCs, so Troll's Tale will display CGA graphics for those machines. If your PCjr will read the disk correctly, then it will display 16-color graphics on your real PCjr.
ReplyDeleteI wonder which of these games support 16 colours on CGA. Because I remember that the Black Cauldron was 16 colours, but Maniac Mansion was 4 colours on CGA. If it's the very same mode on CGA, Tandy 1000 and PCjr, then just little patch would make all games to run on CGA with 16 colours. Patch or some TSR like SimCGA to fool them they are running on Tandy/PCjr.
ReplyDelete"Because I remember that the Black Cauldron was 16 colours, but Maniac Mansion was 4 colours on CGA. If it's the very same mode on CGA" - No, it's not. Black Cauldron can show ~16 colors using its 640x200 composite color mode, but Maniac mansion only supports ~4 colors using its 320x200 composite color mode.
ReplyDeleteThere is a program called Tand-Em to simulate the Tandy/PCjr. for self-booting disks, but its very much out of date now.