Noob Atari 8-bit development and graphics questions

[emkay]

For a better understanding some examples of real working games:

 

Mode 4, using character movement:

 

 

Mode 4 using Software Sprites

 

 

Both Games done by a real genius back in the 80s.

 

Mode 6:

 

 

Looks not so bad, particular if you have a look at that the Game is written in Basic.

 

Mode D:

 

 

THE promotion game for the 8 Bit Ataris 1979/80 . If fact it is 3D .

 

A more modern Mode D Candidate:

 

 

 

 

Have a look at the parallel working graphics FX and the digital Sound .

 

Mode E:

 

 

 

 

 

Mode F:

 

 

32 Bytes width allows to adapt Games from the Sinclair Spectrum, fast enough.

 

 

 

 

Also Hires allows smaller moving objects, allowing more complex games.

[E474]

Hi,

 

    One thing that seems to be missing is a tile editor for the 8-bit. This thread 

points to some online utilities (I haven't tried them), but I don't think there is anything that will let you choose 8-bit fonts and make arbitrary sized tiles/tile maps (e.g. levels).

 

Hope this helps!

[+slx]

If you want to do it very Atari style you could also consider programming in Action! which has a C-ish syntax and is probably the fastest you'll get short of assembler. 

 

Haven't seen it mentioned here (or overlooked it): due to the full-height nature of Atari Player/Missile graphics and the ability to multiply width they are also commonly used as overlays or underlays to add some extra color.

[emkay]

4 hours ago, slx said:

If you want to do it very Atari style you could also consider programming in Action! which has a C-ish syntax and is probably the fastest you'll get short of assembler. 

 

Haven't seen it mentioned here (or overlooked it): due to the full-height nature of Atari Player/Missile graphics and the ability to multiply width they are also commonly used as overlays or underlays to add some extra color.

Hm. If I'd written that,  there would have been a whole string of blaming toward my direction

Ofcourse it is a waste of resources to use the PMg for small moving objects. 

 

 

And... People blame for a missing "Elite" on the Atari. Having a look at this Video, it is a shame, the game never has been released.  Elite is crap compared to the real Star Raiders 2 game. Particular if you look at the Hardware it runs on.

Hehe… If you look at POUET.NET. Someone should add a rule there "Demos of a dedicated year" . Let's just set the Year 1981 as a rule. Well, the Software is released later, but it could only run on Systems of that time.      

 

 

That game chews Elite and spits it out by the included 3D functionality. And there is not a slight Raster Trick used. Particular the 360 Degree turns and moves are breath taking. 

 

 

[zzip]

On 10/8/2019 at 3:34 AM, Turbo Laser Lynx said:

Hey thanks! I did read about this in wikipedia, but I was hoping that there would've been a simpler "multicolor mode" There seems to be a hell of a lot of graphic and sprites modes on the Atari 8-bits This is obviously both good and bad. It's good that it gives you a lot of possibilities, but it makes it harder to learn and produce games for everyone. Don't get me wrong, I've already fallen in love with the Atari 8-bit computers.

I would recommend learning how the basic graphics modes work by using BASIC because you can test things out in real time.    Let's say you type "graphics 15" at the READY prompt, that will put you in 160x192 mode, with a 4-line basic prompt at the bottom,  you can then experiment with plots, drawtos, setcolors, to get an idea of how the modes look, how colors work.   You could even create some P/M graphics an move them with POKE commands,  try the different modes (I don't think this works with the 3 GTIA modes though)

 

Once you are comfortable with the vanilla modes,  then learn about Display Lists-  these are basically a description of how to display the screen, and it is very easy to mix graphics modes on the same screen

 

Once you understand display lists,  then you should learn about "Display List Interupts".   This is a common way to get more colors on screen, and more colors into P/M graphics.   You can use them for other things, like splitting a Player and repositioning it to effectively turn it into two or more players

 

[emkay]

Having a look at the aimed game. If there aren't more than 2 "Sprites" on the Screen, the closest method (to C64)  is of course to use ANTIC 4 (Graphics 12) plus multicolor PMg.

 

Raster Tricks, like splitting the PMg using Displaylist Interrupts, might help at the 1st sight, but it complicates everything.  You might get hard times to move those objects vertically. That's particular why you don't have background graphics in International Karate. Every time, when a game needs quick response, things get rather limited.

 

I see, you used character movement in the VIC20 Version. This could be an option on the Atari as well, if you have more "Sprites" to move.

You have to keep in mind that the Atari is older than the VIC20. The hardware never got updated for any better result in Graphics and Sound. It has a lot advantages but also a lot limits you cannot ignore. Particular the Details in Games get rather low, if speed is needed.  

While the Atari solved late 70's Software ( wich means those Atari 2600 updated games and 3D )   with brilliance ...

The Part of just creating a scrolling Game with Sprites (as has been usual after the C64 entered the market) is a total mess.  

 

The range of those "games" can be from 50 (60) fps Games that look like Atari 2600 to still images that can look like a 32 Bit Machine. Finding the perfect balance can take more than 40 Years, as after all this time several Genres never found their way to that machine

 

So it could be interesting to read more about the project. It could help to shortcut things.

 

 

[Turbo Laser Lynx]

Thanks to everyone helping out once again!

On 10/11/2019 at 12:36 AM, zzip said:

Once you are comfortable with the vanilla modes,  then learn about Display Lists-  these are basically a description of how to display the screen, and it is very easy to mix graphics modes on the same screen

 

Once you understand display lists,  then you should learn about "Display List Interupts".   This is a common way to get more colors on screen, and more colors into P/M graphics.   You can use them for other things, like splitting a Player and repositioning it to effectively turn it into two or more players

 

On 10/11/2019 at 7:41 AM, emkay said:

Having a look at the aimed game. If there aren't more than 2 "Sprites" on the Screen, the closest method (to C64)  is of course to use ANTIC 4 (Graphics 12) plus multicolor PMg. 

 

Raster Tricks, like splitting the PMg using Displaylist Interrupts, might help at the 1st sight, but it complicates everything.  You might get hard times to move those objects vertically.

 

On 10/11/2019 at 7:41 AM, emkay said:

I see, you used character movement in the VIC20 Version. This could be an option on the Atari as well, if you have more "Sprites" to move.

 

Now when I already know more about the Atari 8-bits, I was indeed thinking of ANTIC mode 4 with multicolor PMG's + character movement for "enemies". Absolutely not to emulate the c64 or something silly like that, but partly to "keep it stupid simple" (if I'm ever going to be able to port this game to a lot of systems) and partly since that still seems to be the most used mode, in other words probably the most characteristic mode for A8 so that people would most easily recognise it as a A8 game. If I get the feeling that more color is absolutely needed, or if I get generally excited I'll look into the display lists and display list interupts. Perhaps later in a second game if not the first time around.

Speaking of that, does anyone know if the Atari 8-bit is the originating system/computer for those lovable double wide chunky pixels? Or is there an even earlier originator? For a little while I thought it was the defining visual thing of the C64, but obviously I recently found out the Atari 8-bit had them before. Luckily the C64 palette is unique and unforgettable Also the Amstrad CPC has got the double wide pixels in its most characteristic graphics mode, but that one is from 1984. I haven't looked into the 70s home computers that much yet other than the A8.
 

Edited October 14, 2019 by Turbo Laser Lynx

[emkay]

TheThat "double wide" pixel seems to be a tribute to NTSC . Single Pixel Colors haven't been possible back then.

You know, the Atari has Hires Colors on an NTSC System ?

Seems, they did chose the double wide pixels to get more stable and "real" colors to the screen.

A lot Home Systems (TV Game Consoles) used that too.

 

[Turbo Laser Lynx]

Sorry I'm not sure I'm following here, I mean hi-res single pixel modes do have color (just less colors)? I don't know much about NTSC though, so might be something I'm missing here. ? I thought the double wide pixels were about saving ram as explained in this video here?
 

 

[R0ger]

I think emkay talks about what's usually called artifacting. In hires mode, especially when used with black and white, every pixel has slight color tint. On PAL it's not so pronounced, and the logic of it complex, but on NTSC, it's simple. It's based on X coordinate. If it's odd, the pixel is shifted toward cyan, and if it is even, it's shifted toward magenta. And it's pretty strong. If you want to have white color, you have to use two pixels side by side.

 

As for other differences between PAL and NTSC, PAL has 50Hz and NTSC 60. Both have same horizontal resolution and timing, NTSC simply has less lines visible. VBI is triggered on the same line though. This means, that there is MUCH less time from start of VBI to start of next frame. Generally, you have less time in NTSC, as more time is spent generating video per second. And if your game logic is based on framerate, it will run at different speeds on PAL and NTSC.

Then there is different palette. More or less NTSC colors are shifted one hue step up, just check Altirra's color editor, you will understand.

Most games are made for NTSC, and they simply run slower, and have wrong colors on PAL. Some games are designed for PAL, and simply don't run on NTSC at all. And few run on both system at the same speed, with the same colors.

[carlsson]

As for double width multicolour mode, the VIC-20 has it too. The gospel is that the VIC-I chip was developed in the late 70's to be sold to arcade game manufacturers but Commodore never found a buyer so they repurposed the chip for an own home computer. Exactly how late 70's is hard to tell, and at least Commodore had ongoing plans for a 40 column version of the VIC-I chip before even the VIC-20 was released, but for technical and economical reasons they never released a such model, instead working on the new VIC-II. For that reason, it is also hard to tell if the very early prototype versions of the VIC-I had the same properties the final chip got.

 

We know as much as the A8 was released to customers in late 1979, hardware prototypes ready already sometime during 1978 IIRC. The VIC-I chip was briefed at CES in January 1980, with a computer built around it in June and the VIC-1001 released in Japan in Sep/Oct 1980. In the time frame between e.g. Nov 1979 and Jan 1980, likely Commodore could not have had time to add features from Atari and if they did, why not add hardware sprites which also existed on the TI-99/4 from Sept 1979 and eventually on the Intellivision based on a GI design that had been floating around for a few years.

 

Probably there is another, earlier example of multicolour but I can't point to which one. Neither the TMS VDP nor the GI STIC have those double width pixels, and I'm not sure if e.g. the Apple II has them as well.

[emkay]

The thing about the double pixel isn't that difficult.

The VCS was build for NTSC and stable colors. Raster-Resolution "160x192" ... about 1977...

[Turbo Laser Lynx]

Unfortunately it seems like using colors on the apple II is also done by double wide pixels, I was rather hoping Atari would've been first. According to wikipedia apple II was released in June and the VCS in September. However - I would need to check how the Fairchild Channel F did colors, since it came out before both the VCS and Apple2. At this point I'm not aware of any earlier computers that display color, perhaps there are some even further back. @emkay You're right that it indeed seems that it was the NTSC standard that brought about different solutions for colors in different places at the same time frame.
 

 

[+Stephen]

Also - the Atari only scrolls in colour clocks, not hi-res pixels as opposed to the C64, which can in fact have 320 pixels scroll and colour resolution.

[carlsson]

Don't worry about the Fairchild Channel F. It has a resolution of 128x64 pixels, of which about 102x58 are visible on the screen. IIRC background can be solid black, white, grey, light green or light blue, with foreground colours red, blue, green. All pixels are equally chunky, so there is no hires monochrome + lowres multicolour modes. If you are curious, rather look at something like the Bally Astrocade, which is post VCS but prior to A8.

[Turbo Laser Lynx]

On 10/15/2019 at 12:13 AM, carlsson said:

Don't worry about the Fairchild Channel F. It has a resolution of 128x64 pixels, of which about 102x58 are visible on the screen. IIRC background can be solid black, white, grey, light green or light blue, with foreground colours red, blue, green. All pixels are equally chunky, so there is no hires monochrome + lowres multicolour modes. If you are curious, rather look at something like the Bally Astrocade, which is post VCS but prior to A8.

I just got a litte bit curious about the history of these things. I found the Channel F kind of interesting since it's so unknown, still it was the first one to have cartridges, and it has colors earlier than the apple II  (according to Wikipedia at least), I remember Wozniak claiming somewhere to have invented computer color graphics, maybe they were invented simultaneously "all over"? Need to check up more history for fun.
 

On 10/15/2019 at 12:13 AM, carlsson said:

Roses are red, violets are blue

There's always a graphics mode better than the one used by you

Here's my poetic response, the last word is in Swedish though. Roses are red, violets are blue. I love my VIC tjuguuu!

Edited October 16, 2019 by Turbo Laser Lynx

[zzip]

12 minutes ago, Turbo Laser Lynx said:

I just got a litte bit curious about the history of these things. I found the Channel F kind of interesting since it's so unknown

My friend had one.    While it did color, I remember that however  it did it made the TV screen buzz like crazy

[carlsson]

Not sure if the Channel F is unknown really. Pretty well documented with development resources, all games dumped and emulated, rather big company who stood behind it etc. A couple of years ago a lengthy article was posted about the origins, how it started as a video game using the Intel 8008 or possibly 8080 (a bit unclear) and when the developers approached Fairchild, had to adopt it to use their own F8 CPU instead.

 

Colour computer graphics in general probably predates a little earlier, though it was a matter of making it practical and economical. I found the Cromemco Dazzler from 1976, an add-on card to S-100 bus machines like the Altair 8800. It generates colour graphics before the Apple II, though at a lower resolution.

 

It came bundled with this kaleidoscope program:

 

 

Edited October 16, 2019 by carlsson

[Alfred]

 Why all the obsession with Antic 4 ? I get it about the 5 colours, but it's character based, so either you can only have 4 single colour players, or more likely two multi-colour players. Any enemies would have to be animated via character set and means they'd have to be full cell-size, so no background could show through, and they can only move in character width jumps, right ? So why not use E mode where you can have your multi-colour PMG guys and still smoothly animate other moving objects ? I don't get it.

[emkay]

17 minutes ago, Alfred said:

 Why all the obsession with Antic 4 ? I get it about the 5 colours, but it's character based, so either you can only have 4 single colour players, or more likely two multi-colour players. Any enemies would have to be animated via character set and means they'd have to be full cell-size, so no background could show through, and they can only move in character width jumps, right ?

 

 

It is always depending, on what you want to reach with the FINAL production.

 

Have a look at the attended image.  This type of games have never been made on the Atari: The strength of ANTIC is to use the full screen. Doing graphics that way, means to have no borders, thus the single pixel gets relatively smaller.

The both guys can be animated, using ONE character set, and it allows to have a scrolling background with some limited details in dedicated ranges.

Believe it or not, the two guys can be moved in 1 Frame (50 or even 60 fps) , if the coder wants to do so.

 

 

 

Btw.: the little small lilac thingy to the lower right is a 3 color PMg object.  

 

Quote

 

So why not use E mode where you can have your multi-colour PMG guys and still smoothly animate other moving objects ? I don't get it.

 

Because it's all said there ?

 

 

Edited October 16, 2019 by emkay

[Wrathchild]

Its not been exploited yet (to my knowledge) but modern bank switching cart devices with their capacity can be stuffed with a greater number of pre-processed, e.g. shifted, software sprites and masks and then use to more efficiently rendered into a frame, so that closes the gap between the time to render soft-sprites. 

The other advantage is with tiled type backgrounds as drawing a tile is a case of setting a few characters rather than x*y/4 address, and similarly animating a tile is only a case of updating the characters within the font rather the each area where it is drawn.

[emkay]

15 minutes ago, Wrathchild said:

Its not been exploited yet (to my knowledge) but modern bank switching cart devices with their capacity can be stuffed with a greater number of pre-processed, e.g. shifted, software sprites and masks and then use to more efficiently rendered into a frame, so that closes the gap between the time to render soft-sprites. 

The other advantage is with tiled type backgrounds as drawing a tile is a case of setting a few characters rather than x*y/4 address, and similarly animating a tile is only a case of updating the characters within the font rather the each area where it is drawn.

 

Modern (?) Bank Switching. Of course you could set every animation pointer of the PMG , and the Screen Memory, and the character Set, and different CPU Code ... to a new Memory Bank on a Device that offers endless RAM. But, things should be a little realistic, if people talk about "what's possible on that old machines" . Actually, when the XE entered the eastern Europe Market, it was "normal" to have up to 4MB in a computer. 1MB would fit more to the class of the named hardware. The early 80s allowed 128K , later 256K RAM Expansions. So, in that given rule of the "8-Bit Era" 320K should be the upper limit for a working game that allows to say "Look, what the Atari can do" . Everything above that is just a "Video-Player" . Several Levels stored on such a device, of course allows bigger values.   

[emkay]

Just for Fun: The size comparison of a Atari Screen and a C64 screen: 

 

 

 

 

It's the same Pixel size.

 

 

 

 

 

[emkay]

This looks more funny:

 

[emkay]

Or, how about this one: