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CENTRON 3D - Title Screen Shot

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Hi Guys, finally our intro screen is done using our new CMODE graphics mode.

 

To use our new graphics mode we had to create a pixel editor and this is why it's taken so long to do.

Cmode itself took over a week to complete in pure 6502 and our pixel editor took another week

and is programed in BASIC and 6502. Some routines in BASIC was far too slow so 6502 was the answer.

 

More screen shots will be available as they come and a YouTube video of Centron 3D in a few weeks.

 

Thanks guys, hope you like it.

 

Pete

Manager

RPC-GAMES !

 

 

 

post-39099-0-64223000-1400895830_thumb.jpg

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Hmm GTIA but all colours and luminances... 4scanline size pixels, not possible you're using blending this way, hmm... Can you assure that on a real machine there's no flicker?

Of course I wanna know how you guys get this but I don't think you will say, right?

 

Will the in-game also be in this resolutions and with these loads of colours?

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Even if they are using interlace/flicker as in APAC/TIPP/WHATEVER, by having the "pixels" double-high and alternating, they may seem more "solid" and may trick the brain a bit more, providing greater persistance of vision.

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I think I have an idea how this mode could be done. It's not entirely flicker free and you would only get 81 colors on screen (9 lumas x 9 chromas). I wonder if this was the method they used ...

 

You need to set a low res Graphics 7 mode. You will be using two display lists. The first one is a normal Graphics 7 display list. The second, uses a whole bunch of LMS trickery, so that the positions of every group of 2 scanlines are swapped with each other. So while the first screen's display list memory would go like this (using scan line numbers):

 

0 - 1 - 2 - ...... 94 - 95

 

The second display list, using LMS trickery, would need to have the screen lines ordered like this:

 

1 - 0 - 3 - 2 - 5 - 4 - 7 - 6 .... 95 - 94

 

So basically you are swapping every two scanlines with each other in the second DL.

 

Now for the real tricky part. You have to stripe the screen between modes 9 and 11, in a method similar to APAC.

 

Then, you have to swap between the two display lists every vblank, and simultaneously alter the striping each vblank as well. On even frames, the screen will go 11-9-11-9, while on odd frames the screen goes 9-11-9-11.

 

In theory, this should get you 80x48 resolution (what the above screen appears to be) at 81 colors. It's not entirely flicker free, but would be marginally easier on the eyes than full frame flicker.

 

The reason for the lowered color resolution is, that when you engage the GTIA modes in graphics 7, you only get 9 chromas or lumas.

 

I counted the lumas and chromas in the above picture, and can only detect (to my eyes anyway) 9 luma level and 9 chroma level, so it's possible the above screen was produced using a variation of this method. The chromas in Graphics 7.11 run in these colors: 0 (black), 1 (gold), 2 (orange), 4 (red), 5 (purple), 6 (indigo), 8 (blue), 9 (gray-blue), 10 (blue-green). These appear to be the chromas used in the title picture above, so I think it's highly likely this is the method used in this example.

 

If this was indeed the method used to do this picture, there are other variations possible too:

 

Doing a 9-10 switch instead of a 9-11 switch will give you a 159 pixel (HIP mode) horizontal resolution, while lowering your colors to 63 (9 luma x 7 chroma), or about 16-20 grayscale if you use monochrome settings, and would flicker less. One could also do a CIN type mode (GTIA normal-11) to get 36 colors (4 luma x 9 chroma) at 160x48. Or by doing a PCIN-type setting (GTIA normal-10) you get maybe about 20 colors, but a lot less flicker since 4 of the color registers are shared on both screens.

 

There is also the possibility of using what I call Super 9 (or Double-9) mode. The entire screen stays in GTIA 9 but you are altering the COLBK register (background color) instead of the GTIA register. The two colors used would ideally be colors on opposite sides of the color wheel (red-cyan, blue-yellow, or green-magenta) and should get you a duo-shade 81-color screen but with less flicker than the APAC style setting I described above.

 

It's also VERY possible to use this in a game, as basically you would only need memory for a Graphics 7 screen to make this work.

Edited by Synthpopalooza
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In my experience it's just easier to do graphics in whatever PC-based package you want to use, taking into consideration pixel aspect ratio and palette limitations. Then just save as raw or BMP and do a quick/dirty Basic program that imports the data and writes to a file on the Atari.

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@rpc_games: that indeed is a nice intro screen. That is a good appetizer for more!

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Nice picture Pete. Although it is blocky, the extra colours means that it still shows nicely. And a 3D game with such colours (due to the movement) will look good. Space Harrier managed to get away with being blocky by moving a lot, therefore you didn't notice how big the pixels were. I think it is an excellent compromise in order to make things possible on the Atari 8-bit.

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Nice and colourful but as to what the games about??

 

An astronaut, an old car and a street light??

 

But nice to see a screen shot..

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Nice and colourful but as to what the games about??

 

An astronaut, an old car and a street light?

It's DeLorean with open gull-wing door.

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Hi Guys !!! :)

@ CATERPIGGLE: Centron 3D should work on both PAL and NTSC.

 

@ JOSE: Your right, we're not going to say how CMODE works. Sorry, company policy.

The game will be using all colours on screen at once and in that res, even on the game grid :) All colours.

We will try and shade the graphics to smooth out the blockyness, but we need some cycles for the main

game code as well. The software sprites will have as many colours as they need.

Think of it as a low resolution VGA mode. Software sprites will be 16 x any height, but we only have 64k so we

can't go too sick with extra large multi coloured sprites. Sure the 130XE has 128k so we can store data in there but

not everyone owns a 130XE.

 

@ SYNTHPOPALOOZA: Your close but that's not how CMODE works, but your very close :)

 

@ SNICKLIN: Thanks :), We had to sacrifice resolution for memory. We want it working on 64k machines.

If everyone had 128k we could of had a higher res with more colours.

 

@ Mclaneinc: What the game is about is......... Will be revealed when the YouTube video is released.

An old car, street light and Astronaut??? You got the Astronaut right. It's a Delorean with the door open :)

 

@ZuluGula: CORRECT !!! 10 points to you :)

 

Sorry it's taken so long to get a screen shot but it's all coming together smoothly.

I'd forgotten how FUN it was programming the Atari 8 bits. :)

 

Pete

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Sure the 130XE has 128k so we can store data in there but not everyone owns a 130XE.

 

Oh, I don't think you'd have to worry too much about the limitations of 64k of ram around here.

Even 'back in the day' many of us were running with quite a lot more.

Edited by Reaperman
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It's a Delorean with the door open :)

 

I hope that you don't plan to release the game until October 21rst 2015...

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Now I am curious. I am going to wait till there is a preview of the game ... what prize do I get if I figure out how you did the mode? :) (promise not to spoil the secret for everyone) ... but I knew I was pretty close on the Graphics 7 GTIA thing. The 9 chromas/lumas gave that part away

 

But yeah it looks awesome. Shame you couldn't do it in Antic 5, you'd have 5 extra colors and shades to play with.

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If you decide to use bankswitching cart like atarimax you have almost unlimited space so you could make your game as beautiful looking as possible without worrying about memory (you have a changing 8k window on a000-bfff).

 

If you stick to 512k max you even could release a version that runs from myide 2.

 

Just a suggestion.

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One thing that I do find amusing with the screenshot is that there appears to be grass in the background. Grass needs oxygen. But there probably isn't any as the astronaut has his suit on :)

 

However, yes, it's just fiction, not reality! Did make me smile though.

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One thing that I do find amusing with the screenshot is that there appears to be grass in the background. Grass needs oxygen. But there probably isn't any as the astronaut has his suit on :)

 

We could say that the air pressure is low, but oxygen is present, that is why a suit is required?

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I didn't even think it was an astronaut - looks more like the business end of a .45 Magnum.

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I didn't even think it was an astronaut - looks more like the business end of a .45 Magnum.

 

That's what I thought at first too. But then after I looked at it a few times...

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I think I have an idea how this mode could be done. It's not entirely flicker free and you would only get 81 colors on screen (9 lumas x 9 chromas). I wonder if this was the method they used ...

 

[..]

 

When it uses interlaceing the picture is misleading, as it shows solid colors.

TBH I dont like the flickering (PAL region). that is the reason why I do not like your experiments that much.

However, in a game it might be acceptable. "Space Harrier" flickers to much for me though. But it was mentioned that this 3D game uses shading, so the flickering should be too bad.

As for the low resolutions, on a real CRT TV-set (luckily I still got my old 30cm TV-set) it should be fine. In an emulator or with a modern LCD display it could be ugly. We will see in a few weeks :)

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Oh, I don't think you'd have to worry too much about the limitations of 64k of ram around here.

Even 'back in the day' many of us were running with quite a lot more.

My vote goes for 64k support. I have couple of 800XLs that would be very disappointed if such a great game as Centron wouldn't run on them ;)
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@ Snicklin: hahahahaha You crack me up :) hahhaha :)

 

@ Yautja: We are hoping to release it in a few weeks. Why do you say that?

 

@ ProWizard: I would Love a memory cart but 30 cans of Coke and 2x 1050 Drives and 1x XF551 is enough :)

 

@ Creature XL: We never tested CMODE on a normal CRT TV. We use a Commodore 1084 monitor.

I have an old TV in the shed at home, I'll test it and see how it looks. Great idea :)

 

@ Synthapopalooza: No, we are offering no prizes. :) Oh I shouldn' say this but your wrong with the GR7 mode.

 

To everyone, I have uploaded the 1st intro screen to our official website. This pic uses ALL the CMODE colours.

 

See here www.rpcgames.com.au

 

Have fun guys :)

 

Pete

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I hope that you don't plan to release the game until October 21rst 2015...

 

@ Yautja: We are hoping to release it in a few weeks. Why do you say that?

 

DeLorean as "Back to the Future" reference => "Back to the Future" Day (October 21st, 2015)

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Let's see... Looks like a lynx game ;) appreciated the work and every new release is a plus...

 

I am not a fan of having this kind of "secret" about the mode used.... We are in 2014 where fandal, tebe, xxl, etc release stuff and talk open about it... Or even release source code... (Reminds me Arsantica sources to publish).

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