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Magnavox Odyssey 2: 64 Shapes?


BladeJunker

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I've been looking over the oldest school game systems to see what they can do graphically, one such system is the Magnavox Odyssey2.

 

I found all the sprite performance basics under the Wikipedia page but haven't had any luck with what all 64 shapes or characters look like? I also can't find an approximation of the 16 system colors listed anywhere either.

 

Even if I deduct 26 letters and 10 numerals I still have 28 8 by 8 pixel characters unaccounted for. Anybody know of a level editor or someone who's exported the data from the MO2 ROM or something? Even if I manually extract from every screenshot I can get my hands on it would be a lot of work and I could still miss one.

 

Any place you know of where I could ask even would be most appreciated as my searches haven't found a heck of a lot? :)

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Any place you know of where I could ask even would be most appreciated as my searches haven't found a heck of a lot? :)

 

MagnavoxAge.com. ;)

 

All kidding aside I have never come across a site dedicated to the Odyssey2. I would even hazard a guess that this site might hold the largest collection of Odyssey2 fans you can find.

Edited by jeremiahjt
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There are several good sites, but you'll probably need to look for videopac.

Dan Boris' site has lots of great info, including an awesome pdf.

http://www.atarihq.c...shtml#techfiles

 

It has a color list and character map description.

(Not with actual images of the characters tho, more descriptions).

 

desiv

Well I'm sure I can find it somewhere if I try Videopac, thanks for the link. :)

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There's also this: http://www.the-nextlevel.com/odyssey2/

 

But I think what you're looking for may be this:

http://home.kpn.nl/~...000_symbols.gif

Another link thanks, I don't have a MO2/VP but its on my list and fun to learn about in the mean time.

 

Yep that's the 64 or 63 it looks like shapes I was looking for. Its surprising since I didn't expect some of them to be so specific like the people and boats, I thought for sure those would have been custom sprites. Well its not quite ANSI/ASCII level but I see how they would fit together to make a number of games.

 

Thank you very much. :)

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The whole notion behind the Odyssey2's built-in character set is that if they built the sprites into the machine, they could cut corners everywhere else. That worked pretty well for Magnavox for about a year, until licensed arcade games with distinctive mascots demanded more than the Odyssey's handful of robots and abstract shapes.

 

On the plus side, I can't recall a single Ody2 game that had any flicker in it. The machine could push around a lot of objects at once, provided they were all boulders and pale robots.

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The whole notion behind the Odyssey2's built-in character set is that if they built the sprites into the machine, they could cut corners everywhere else.

 

If you look at 0x32-35 it looks like the O2 doesn't even flip these sprites in hardware. That's really cutting corners!

 

On the plus side, I can't recall a single Ody2 game that had any flicker in it. The machine could push around a lot of objects at once, provided they were all boulders and pale robots.

 

True. The smoothness of O2 graphics even leaves a favorable impression today.

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A few games, Frogger and Backgammon comes to mind, updated sprite registers mid-screen to achieve a larger number of sprites. The catch is that timing is different between NTSC and PAL units, so such a game would run on either PAL or NTSC, but not both, unless you make a second version for the other system.

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  • 4 years later...

I may be a bit late, but I just found this thread.

A character table of all predefined characters, together with their exact bitmaps, can be found in the Appendix of the manual of Videopac 9 "Computer Programmer".

Do you still need it?

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There's also this: http://www.the-nextlevel.com/odyssey2/

 

But I think what you're looking for may be this:

http://home.kpn.nl/~rene_g7400/vp_info/G7000_symbols.gif

THANK YOU for finding that, I was looking for that same image (I think it might be from the Computer Intro manual?) but could not find it anywhere.

 

I wanted to use it as a background someplace. Now I wish I could remember why I wanted it. IT'S SO BEAUTIFUL

 

G7000_symbols.gif

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  • 3 weeks later...

A few games, Frogger and Backgammon comes to mind, updated sprite registers mid-screen to achieve a larger number of sprites. The catch is that timing is different between NTSC and PAL units, so such a game would run on either PAL or NTSC, but not both, unless you make a second version for the other system.

The second catch is that unlike almsot every other systems, the video is generated differently, to my understanding, the game "picture" is realized internally as a whole complete picture then this pciture is sent to the video chip to be turned into a 240p signal. This make classic video based tricks harder to do since the system doesn't allow you to change something by line to make it flicker at 60 htz and add colors to a sprite, for example.

 

On the other hand, it mean that the video was less prone to flickering AND that the timing issues between PAL and NTSC machines are less important - the biggest issue is that the games had to be reprogrammed for the different resolution, but there isn't any speed difference between a PAL and a NTSC game.

 

The whole notion behind the Odyssey2's built-in character set is that if they built the sprites into the machine, they could cut corners everywhere else. That worked pretty well for Magnavox for about a year, until licensed arcade games with distinctive mascots demanded more than the Odyssey's handful of robots and abstract shapes.

Let's recall too that the Videopac is powered by a microcontroller, which is a stripped down microprocessor. The Intel microcontroller used in the Videopac was used for example in pocket calculators, in remote controls in the 90's, in home automation control panels, etc...

As you can guess it's not exactly a powerhouse, so using build-in items meant that the controller had less job to do. It's interesting to note that the Videopac also include a rando number generator and a maze generator, which is why you have several of those games on the machine, because they were quite easiy to make.

 

Using built-in items also mean that you have less things to write : smaller ROMs are possible : cheaper carts : more profit.

Edited by CatPix
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  • 2 years later...

I realize this is an old thread, but it's still showing up for searches so here's some info...

 

The second catch is that unlike almsot every other systems, the video is generated differently, to my understanding, the game "picture" is realized internally as a whole complete picture then this pciture is sent to the video chip to be turned into a 240p signal. This make classic video based tricks harder to do since the system doesn't allow you to change something by line to make it flicker at 60 htz and add colors to a sprite, for example.

 

The O2 actually generates the image on the fly, so you can alter registers halfway through a field to have more than 4 sprites + 28 characters simultaneously on the screen. You just have to make sure you have enough time to update and the data. The 8048 in the O2 runs at 1.79Mhz, which is further divided by 5 "states" for a one byte instruction, or 10 "states" for a two-byte instruction. This works out as between 179,000 and 358,000 instructions per second. This seems like a lot, but (for NTSC) when you divide this by 59.94 (field rate), you have at most 5,972 instructions per field or 22.75 instructions per scanline, and 443 instructions during vertical blanking.

 

The 8244 VDC can control several objects and helps reduce to load on the processor. It will output signals for background color, grid color and position, the 4 sprite colors and 28 (4 x 4 quads + 12 individual) characters that are in it's memory.

 

To change info in the 8244 VDC (video display controller), you have to enable it onto the bus (you would do that in vertical blanking); then you have to turn off graphics to update them; you need to copy the new data over to the VDC byte by byte; and finally need to reenable the graphics again. This will take longer than one scanline. To reposition a sprite, you will need to update 3 bytes (assuming you don't change the bitmap) per sprite. The hardware has a special "copy EXTERNAL RAM to VDC" mode, where the following sequence uses 8 instruction cycles per byte copied from RAM to VDC:

LOOP:

MOVX A,@R0 ;reads from external ram

MOVX @R1,A; writes to VDC

DEC R0

INC R1

DJNZ R2,LOOP

Just copying three bytes takes 24 instruction cycles (longer than a scanline). You could save a few instruction cycles by not using a loop. The following code takes 18 instruction cycles instead of 24 (although it uses 12 bytes of memory instead of 6):

MOVX A,@R0

MOVX @R1,A

DEC R0

INC R1

MOVX A,@R0

MOVX @R1,A

DEC R0

INC R1

MOVX A,@R0

MOVX @R1,A

DEC R0

INC R1

 

To see if a game uses these "mid-screen update tricks", just hold the RESET button down on an actual console. This will halt the 8048 as long as you're holding the button down, and stop any VDC updates. Since the 8244 continues to generate the video signal, you can see what is actually in the VDC memory. If half the on screen objects disappear, you'll know that updates are ocurring.

I think the source of your misconception might be because the O2EM emulator caches parts of the screen to speed up screen updates, and this is why some games (Wall Street, Frogger) have problems running correctly.

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  • 4 years later...
On 6/16/2012 at 7:30 PM, Jess Ragan said:

The whole notion behind the Odyssey2's built-in character set is that if they built the sprites into the machine, they could cut corners everywhere else. That worked pretty well for Magnavox for about a year, until licensed arcade games with distinctive mascots demanded more than the Odyssey's handful of robots and abstract shapes.

 

On the plus side, I can't recall a single Ody2 game that had any flicker in it. The machine could push around a lot of objects at once, provided they were all boulders and pale robots.

It’s just an absolute shame that you only could choose between 64 character sets of tiles for whether both sprites and backgrounds,it’s just ludicrous why they wouldn’t allow to create your own tile sets,even worse bg tile sets are not allowed to overlap each other unlike with sprites so you don’t have much freedom at all other then placing those 64 character sets around the screen without overlapping each other,

This reminds me of those pseudo graphics character sets in both the commodore PET and TRS80 wich only allow you to place text characters around the screen,BUT you can place dots everywhere around the screen to create some impressive pseudo graphical visuals,

now i don’t know if the oddysey 2 also does include letters and dots inside it’s 64 character set but if so,then we might could use those dots for both backgrounds and sprites and place them around on screen to create beautyful visuals (by telling the system by only using those dots and put then in position A or B etc,,, with a different color each etc,,,) that would be great,(especially if we could create an automated toolchain system to convert images into such character set for to make it easier for the user to create graphicart art on the oddysey that way)

another thing i would consider to be great is if we could create -bit dogital sound on the oddysey trough that single sound with some trickery if possible (even the apple || can do this trough trickery) so why not,

and lastly if we could use bankswitching ,then we can free ourselfes out of that 1KB prison and make games as large as we want and do (if possible) wonderful stuff on the oddysey 2 to an certain extend,i was thinking how about a donkeykong,mariobros or pac man port to the oddesey 2 and an improved version of popeye on it,that would be cool,

but as of now to me personally the oddysey 2 feels nothing more then playing certain boring atari 2600 games on a shit rainy sunday in 1982,that’s how it’s feels to me,

only type & tell ,frogger,munchkin,pick axe pete and popeye could makes me want to buy an oddysey 2 and nothing else,not yet.

 

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On 1/9/2024 at 3:28 PM, johannesmutlu said:

It’s just an absolute shame that you only could choose between 64 character sets of tiles for whether both sprites and backgrounds,it’s just ludicrous why they wouldn’t allow to create your own tile sets,even worse bg tile sets are not allowed to overlap each other unlike with sprites so you don’t have much freedom at all other then placing those 64 character sets around the screen without overlapping each other,

This reminds me of those pseudo graphics character sets in both the commodore PET and TRS80 wich only allow you to place text characters around the screen,BUT you can place dots everywhere around the screen to create some impressive pseudo graphical visuals,

now i don’t know if the oddysey 2 also does include letters and dots inside it’s 64 character set but if so,then we might could use those dots for both backgrounds and sprites and place them around on screen to create beautyful visuals (by telling the system by only using those dots and put then in position A or B etc,,, with a different color each etc,,,) that would be great,(especially if we could create an automated toolchain system to convert images into such character set for to make it easier for the user to create graphicart art on the oddysey that way)

another thing i would consider to be great is if we could create -bit dogital sound on the oddysey trough that single sound with some trickery if possible (even the apple || can do this trough trickery) so why not,

and lastly if we could use bankswitching ,then we can free ourselfes out of that 1KB prison and make games as large as we want and do (if possible) wonderful stuff on the oddysey 2 to an certain extend,i was thinking how about a donkeykong,mariobros or pac man port to the oddesey 2 and an improved version of popeye on it,that would be cool,

but as of now to me personally the oddysey 2 feels nothing more then playing certain boring atari 2600 games on a shit rainy sunday in 1982,that’s how it’s feels to me,

only type & tell ,frogger,munchkin,pick axe pete and popeye could makes me want to buy an oddysey 2 and nothing else,not yet.

 

 

This is what made ports so challenging on this system. The only thing you had total control of was the 4 8x8 sprite which could make it very difficult to match the graphics of the game you are trying to port. The cartridge slot does support bank switching up to 8K.

Edited by DanBoris
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On 6/18/2012 at 11:55 PM, Hatta said:

 

If you look at 0x32-35 it looks like the O2 doesn't even flip these sprites in hardware. That's really cutting corners!

 

 

True. The smoothness of O2 graphics even leaves a favorable impression today.

If it is true that the O2 couldn’t even flip or rotate spries in hardware or trough software at all,not only is that disguisting and stupid but also just a waste of space,because they could,ve used that space for other character sets,

becides why didn’t they implemented a hidden free mode sothat you could create your own tile sets for it? So what both philips and magnovox did was adding more for less,

or they should,ve implement character sets in it at all to give the user more freedom to create their own tile sets for it,or they should,ve added waaay more tile sets tile it to give the user more choices and to create their own tile sets with it as well by combining certain tile sets together,

HOWEVER their might be hope that you still do have some freedom to create your own tile sets by placing that availible dot tile next to each other to create you own shapes & forms of objects you aant but am still not 100% sure if this ia actually allowed to make such thing possible,but if so,then it will open up new doors to more freedom for game developers,

here are some examples i found in wich i do believe it should be possible,if it is true that those ghosts in this hacked crazy chase game are made out of copy pasted dots from that 64 character set,then it goes to show that there are such tricks to get around these limitations,

somebody needs to confirm this,

the reason i bring this up is because it would be really cool to see the homebrew scene getting bigger for the O2 and make games for it using all kinds of tricks,how about an actual pacman game using a moddiefied munch man or crazy chase game engine with graphics and sounds close to ghe arcade???

how about a donkeykong game using a moddified pick axe pete engine with graphics and sounds as close as possible to the arcade version???

how about an enhanced version of popeye with better graphics for it???

(yes the soundchip can do more then bleeps & blobs as it also can do noise sound)

now it might be true that better arcade conversions on the O2 might require more ram and rom along with an extra cpu BUT i was thinking how about emulating that chess game module on a future flashcard wich does contain an extra cpu and ram while for extra rom we might could do internally and external bankswitching to get past that 8K limit,so in short there might be a huge potential in the O2,but some homebrewers need to stand up and make it true if it is possible off course😀

C01EDD4C-90CF-4A77-BA7E-ABE810856E99.jpeg

9E3414F0-2180-4908-B4C0-A944495E6D38.jpeg

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1 hour ago, johannesmutlu said:

If it is true that the O2 couldn’t even flip or rotate spries in hardware or trough software at all,not only is that disguisting and stupid but also just a waste of space,because they could,ve used that space for other character sets,

becides why didn’t they implemented a hidden free mode sothat you could create your own tile sets for it? So what both philips and magnovox did was adding more for less,

or they should,ve implement character sets in it at all to give the user more freedom to create their own tile sets for it,or they should,ve added waaay more tile sets tile it to give the user more choices and to create their own tile sets with it as well by combining certain tile sets together,

HOWEVER their might be hope that you still do have some freedom to create your own tile sets by placing that availible dot tile next to each other to create you own shapes & forms of objects you aant but am still not 100% sure if this ia actually allowed to make such thing possible,but if so,then it will open up new doors to more freedom for game developers,

here are some examples i found in wich i do believe it should be possible,if it is true that those ghosts in this hacked crazy chase game are made out of copy pasted dots from that 64 character set,then it goes to show that there are such tricks to get around these limitations,

somebody needs to confirm this,

the reason i bring this up is because it would be really cool to see the homebrew scene getting bigger for the O2 and make games for it using all kinds of tricks,how about an actual pacman game using a moddiefied munch man or crazy chase game engine with graphics and sounds close to ghe arcade???

how about a donkeykong game using a moddified pick axe pete engine with graphics and sounds as close as possible to the arcade version???

how about an enhanced version of popeye with better graphics for it???

(yes the soundchip can do more then bleeps & blobs as it also can do noise sound)

now it might be true that better arcade conversions on the O2 might require more ram and rom along with an extra cpu BUT i was thinking how about emulating that chess game module on a future flashcard wich does contain an extra cpu and ram while for extra rom we might could do internally and external bankswitching to get past that 8K limit,so in short there might be a huge potential in the O2,but some homebrewers need to stand up and make it true if it is possible off course😀

C01EDD4C-90CF-4A77-BA7E-ABE810856E99.jpeg

9E3414F0-2180-4908-B4C0-A944495E6D38.jpeg

I can confirm that the O2 cannot flip sprites, you would have to reverse the actual sprite data. As for a user defined characters set, the problem would have been where to store it. The O2 video chip runs entirely off internal data, it cannot access any other memory on the system. The 8048 can also only access 256 addresses external to the CPU and the video chip already takes up almost all of that. They would have had to add extra memory to the chip and implemented a bank switching scheme to give access to it. Certainly was possible but it seems they did not think it was worth while for what they were trying to achieve with the system.

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  • 2 weeks later...
On 6/26/2012 at 4:20 PM, Phredreeke said:

A few games, Frogger and Backgammon comes to mind, updated sprite registers mid-screen to achieve a larger number of sprites. The catch is that timing is different between NTSC and PAL units, so such a game would run on either PAL or NTSC, but not both, unless you make a second version for the other system.

This is technically an interesting thing to mention, if those sprites registers are updated mid-screen,have you ever wondered how those sprites in both frogger and backgammon etc,, are generated in the first place? Did they inderd used that dot tile 27 ro place them next to each other to create those sprites???

(I cannot imagine how that animated frogger sprite on the title screen was otherwise created on the odyssey 2,since game designers could only choose within 64. Tiles,

so i wonder about those programming tricks on the odyssey 2 wich were later discovered but originally never intended by those designers behind that system😁

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On 1/30/2024 at 9:07 PM, johannesmutlu said:

This is technically an interesting thing to mention, if those sprites registers are updated mid-screen,have you ever wondered how those sprites in both frogger and backgammon etc,, are generated in the first place? Did they inderd used that dot tile 27 ro place them next to each other to create those sprites???

(I cannot imagine how that animated frogger sprite on the title screen was otherwise created on the odyssey 2,since game designers could only choose within 64. Tiles,

so i wonder about those programming tricks on the odyssey 2 wich were later discovered but originally never intended by those designers behind that system😁

 

The animated frog on the intro screen is easy, that's just a combination of the four sprites. The bigger question is, how were the cars done?

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