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TI Scramble - Scramble clone

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I had a go at this one too (the latest beta, not Version 1.0)... first at Wednesday's TI meeting where Klaus showed it on his laptop, then I asked to see it on the "real thing" (F18A equipped), and it behaved a bit odd... the scrolling jumps back and forth, and the missiles get a totally different color when launched, not to mention all sprites flicker like crazy. But it was still somewhat playable. Then I emulated it in MESS and Classic99... in MESS it behaves very well, although I have the feeling that sometimes firing doesn't work. Classic99, as it seems, can't quite handle it... it seems to be quite a deal faster than intended, and even worse, firing doesn't work regularly. By the way, I also emulated an NTSC TI-99 in MESS, and it plays fine on that one as well, only accordingly faster (I think in this case it's faster than the arcade version while in PAL it seems pretty much on par). I didn't try it on my real machine because I have no way to put it there. However...

 

I noticed that thing about the collision detection as well... sometimes you crash into something you don't touch, maybe an explosion of an object you just shot, or a mountaintop that's actually ahead of you. Seems like in this case a collision is registered if you touch any pixel of that character, even if it's empty.

 

Then I noticed that unlike the arcade version, if you die, you spawn near the point where you died, whereas the arcade version sets you back to the start of the zone you died in. The upside of that is that you don't have to replay the stretch you already covered again, but the downside is that you're put right into the action, and often you only have a split-second to decide what to do now because you can't anticipate your spawning point, but if you do a wrong move, it's instant death.

 

But all in all, it's a great feat. I never thought the TI-99 would be able to pull this off, with smooth scrolling. I guess you're doing a lot of tricks here, like running a loop to write to the VDP in CPU RAM, otherwise I don't see how this is even possible. Back in the day they definitely didn't do such good conversions!

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No critic, but only a sidenote:

Yesterday I tested beta1,beta2,beta3,beta4 on my F18A (was a beta tester for Matthew). I think I still have F18A V1.3 software or even older. It didn't look to well. Scrolling was not smooth (totally different than in the youtube clip). The Player Ship was incomplete (only the fuel appeared). Colors appeared like they were off.

I will update the F18A to the latest firmware V1.5 and will retry it.

If that doesn't help, the problem might be somewhere else.

 

Sorry that my testing is limited. The place I tested it didn't have a screwdriver, F18A programmer cable nor another console.

 

Maybe beta5 will work better but I doubt your code is the problem.

 

Will demonstrate Titanium, Mr. Chin on the real console tonight, and TI Scramble on the emulator.

After the update to F18A Firmware v1.5 everything looks awesome now! What a game!

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.. the scrolling jumps back and forth, and the missiles get a totally different color when launched, not to mention all sprites flicker like crazy. But it was still somewhat playable

 

But all in all, it's a great feat. I never thought the TI-99 would be able to pull this off, with smooth scrolling. I guess you're doing a lot of tricks here, like running a loop to write to the VDP in CPU RAM, otherwise I don't see how this is even possible. Back in the day they definitely didn't do such good conversions!

 

I think there must be a problem with your F18A, is your firmware version 1.3 or higher?

 

Regarding how this is done, you have to think about the screen as consisting of transitions between characters rather than discrete characters. Imagine a 4x4 screen consisting of two characters A and B:

 

AAAA

AABA

AABA

BBBB

 

In this screen there are 4 horizontal transitions: A -> A (1), A -> B (2), B -> A (3) and B -> B (4). Let's see the screen in terms of transitions:

 

111?

123?

123?

444?

 

(We don't know which transition characters to put in the last column just by looking at this example - for that we need the rest of the map for the game...)

 

In order to scroll this screen smoothly all we have to do is to change the transition characters gradually, e.g. character 2 should be changed from being all A to becoming all B. After 8 pixels we can't shift the characters any longer; instead we have to shift the entire screen one character:

 

11??

23??

23??

44??

Again, new characters are coming in from the right based on the map of your game.

 

You may think that changing the characters require you to push a lot of bytes from CPU RAM to VDP RAM, but in normal graphics mode there is room for at least 4 different character sets in the VDP RAM (we also need room for sprites, etc.) If we split those 4 character sets into two we have all the frames needed for scrolling 8 pixels. So with this method we can handle up to 128 character transitions, and we can upload them all into the VDP in advance. Then all that requires work of the CPU is to move the entire screen after 8 pixels, and this work can be split in eight between each frame.

 

It's a little more complicated than that, but I hope the basic idea is clear.

 

Now, the problem is to limit the number of transitions to less than 128, or lower than that because you probably also want some non moving characters for status, score, etc. In Scramble I reserve the top 16 characters in each half of a character set for this purpose, so I only have 112 characters transitions left.

 

Then there is the problem of colors. A transition between two characters can only have one color if it's going to look natural when scrolling. So you have to place transitions from red to black in another color set than transitions from green to black, for instance. Fortunately Magellan can help with all this, counting the number of transitions you're using, placing them in the right color sets etc. Without software like this it would be very difficult to make a game like TI Scramble.

 

For smooth scrolling to work, the number of characters you start out with when you design your map has to be really small, 16-24 for instance. If you want more than that you should consider another technique. The thing is that even a screen with very few transitions looks great if it's scrolled smoothly.

 

Hope this explains some of the magic.

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I had a go at this one too (the latest beta, not Version 1.0)... first at Wednesday's TI meeting where Klaus showed it on his laptop, then I asked to see it on the "real thing" (F18A equipped), and it behaved a bit odd...

I believe the F18A Klaus had at the TI meeting was using a pre-release beta firmware. He has reported updating to the latest firmware fixed the problems.

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Compliments Rasmus, the game is wonderful and excellent playability but the flames coming out of the shuttle had to do red, white are ugly; edit the shuttle and it will be perfect.

Excellent game again, I am stunned.

Have in mind some new game?

Bye

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Aside from the excellent conversion of this game, what I find most brilliant is the ability of the game to present on both a stock 4A as well as an F18A-enhanced 4A. Keep setting the bar!

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I believe the F18A Klaus had at the TI meeting was using a pre-release beta firmware. He has reported updating to the latest firmware fixed the problems.

Yes, he said he doesn't have the current firmware installed yet. And I did play it on Klaus's TI-99.

 

Thanks for the explanation how the graphics system works. After a bit of thinking, it's clear to me now. It's not totally obvious how to do this. On the C-64, everyone would be able to do smooth scrolling. ;-)

Of course, the number of possible transitions is limited, for instance, the left half of the fuel tank will always transistion into the right half, and the right half will transision into either another fuel tank or into a blank character (due to the color restrictions). Similar thing about mountains. Of course, this kind of scrolling somewhat restricts the possible complexity of the map. I suppose the TI-99 would still have a hard time doing games like Marble Madness with its rich graphics, unless those get severely stripped down.

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Can we at least have the laser (fire) doubled in size Rasmus as it's barely visible.

 

post-35226-0-64391100-1381610666_thumb.png

 

As I wrote earlier, this would also make the stars bigger. The image shows how it would look, and I don't like it. The image also shows how it would look with virios' suggestion to make the flames red. I like that slightly better, but no. If you want more colors you can play on a F18A.

 

That reminds me, if you want to assemble your personal version of the game, this is very easy to do in WinAsm99. Just create a new project and include the 3 .a99 files from the src directory. There are some nice options at the beginning of scramble.a99 to set infinite lives, fuel, invincibility, turn speech off, etc.The characters for the bullet are defined at line 4859/4860.

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I was thinking, again. I am too lazy to search through seven pages of thread to dig up if Rasmus plans on a cartridge release of "TI Scramble." My thoughts assume he is, so I will continue with them: As cool as a "TI Scramble" cartridge would be, I think it would be cool to have a disk release, as well. I find I have a kind-of legitimacy stigma about disk-based games on the TI because for the most part the cartridge was "the way" to get games and software. Compared to a system like the Commodore 64, it certainly was the best hope for many TI users considering the cost of a disk system. I find it funny that I do not appreciate cartridge games for the Atari or Commodore and think of them as chintzy as I expect games to be disk-based, but my attribution to the 99/4A is exactly the opposite.

 

To that end, I was thinking that when the artwork is conceptualized for the a release, the artist should consider both cartridge and disk labels.

 

EDIT: YES, HE IS; SEE HERE http://atariage.com/forums/topic/213140-building-your-own-carts/?p=2845783

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I was thinking, again. I am too lazy to search through seven pages of thread to dig up if Rasmus plans on a cartridge release of "TI Scramble." My thoughts assume he is, so I will continue with them: As cool as a "TI Scramble" cartridge would be, I think it would be cool to have a disk release, as well. I find I have a kind-of legitimacy stigma about disk-based games on the TI because for the most part the cartridge was "the way" to get games and software. Compared to a system like the Commodore 64, it certainly was the best hope for many TI users considering the cost of a disk system. I find it funny that I do not appreciate cartridge games for the Atari or Commodore and think of them as chintzy as I expect games to be disk-based, but my attribution to the 99/4A is exactly the opposite.

 

To that end, I was thinking that when the artwork is conceptualized for the a release, the artist should consider both cartridge and disk labels.

 

EDIT: YES, HE IS; SEE HERE http://atariage.com/forums/topic/213140-building-your-own-carts/?p=2845783

 

A floppy disk release is a very abstract concept to me. :) I don't have a PEB and have never actually seen one, except on pictures! I don't know how many PEBs were sold in Denmark, but I have never seen one for sale. Even within the whole of Europe they are very rare to find on Ebay. I could probably get one from the US for $200-$300, but then I don't really have room for it, and I wouldn't know how where get floppies either. Basically I'm very happy with my nanoPEB, but there something magical about a cartridge, and it's also much more practical if, for instance, my 6 yrs old son wants to play Scramble.

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A floppy disk release is a very abstract concept to me. :) I don't have a PEB and have never actually seen one, except on pictures! I don't know how many PEBs were sold in Denmark, but I have never seen one for sale. Even within the whole of Europe they are very rare to find on Ebay. I could probably get one from the US for $200-$300, but then I don't really have room for it, and I wouldn't know how where get floppies either. Basically I'm very happy with my nanoPEB, but there something magical about a cartridge, and it's also much more practical if, for instance, my 6 yrs old son wants to play Scramble.

 

True, indeed. Illustrates my point about the perception of disk software for the TI. In the US it is not too difficult to find a PEB: between eBay and Craigslist I reckon see at least one available at any given time. Then there are those hoarders who have three or four and really they just sit around collecting dust because the things are beasts and you rarely need a replacement. I have two and am probably going to get rid of my second unit now I have a CF7+. That said, I would be happy to make disks for a release as I have a bunch of blank, never-been-used 5.25" disks. Considering the proliferation of PEBs I figure 10 would be enough, even if just for the novelty or for a few purists who refuse to touch new devices or prefer the esoterica of having their TI linked to a PC via serial and nothing else.

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Holy shiiiiiiiiiiiiiiiiiiiiiiiit!

 

My flabber has been well and truly gasted!

 

Damn Mark! I need a friggin cultural dictionary to understand your expressions... No clue what you just said :P

Amazing work Rasmus! Who is going to demo your 2 games at the Faire?

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Then there are those hoarders who have three or four and really they just sit around collecting dust because the things are beasts and you rarely need a replacement.

 

I am so thankful that the hoarders are out there! Without them many of the old TI's would have been junked and a lot of us would not be able to have the real deal.

 

Yes, those PEB's are beasts! They are built like tanks, and amazingly after all these years still work. Actually the TI consoles have held up pretty dard well over the years too. In my experience not to much of the original TI has broken down, while I hear about other 3rd party stuff going T.U. all the time. I just wonder how much longer we have before our consoles start to get component failure due to age.

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I am so thankful that the hoarders are out there! Without them many of the old TI's would have been junked and a lot of us would not be able to have the real deal.

 

Yes, those PEB's are beasts! They are built like tanks, and amazingly after all these years still work. Actually the TI consoles have held up pretty dard well over the years too. In my experience not to much of the original TI has broken down, while I hear about other 3rd party stuff going T.U. all the time. I just wonder how much longer we have before our consoles start to get component failure due to age.

 

So long as they get rid of them, yes. I still have a large stash of equipment which I am slowly whittling down because I simply cannot store things anymore. I keep a VERY small selection of specific items around for parts, the rest have to go to a loving home or, sadly, the dump (Goodwill et al around here generally will not accept "vintage" computers.)

 

I am planning to go through all of my stuff soon and replace electrolytic capacitors. Some things I have I will be replacing power supplies with something more modern. For instance, all the brick power supplies for my Commodore floppies (and other things) with switching power supplies. There is a guy on eBay I bought a new supply for my Atari 130XE who also sells USB to Atari cables for USB chargers which provide 1A or more power. I have been giving that thought for my CF7+.

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There is a guy on eBay I bought a new supply for my Atari 130XE who also sells USB to Atari cables for USB chargers which provide 1A or more power. I have been giving that thought for my CF7+.

 

You might also consider Sparkfun.com

This is the supply I'm using for my Nano-PEB <CLICK HERE> and it's been working great!

With shipping it only came to a grand total of $9.99 and it has the proper end on it.

Edited by Kevan

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The game is indeed incredible good looking on my F18A, it plays like an arcade! The only problem I had was getting it to switch to the non F18A mode, via the F key. Either the program crashed afterwards, or didn't switch the mode.
I was using tiscramble-1.0.zip for this.
F18A has Firmware v1.5 now.

This ported game deserves so much credit!

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Damn Mark! I need a friggin cultural dictionary to understand your expressions... No clue what you just said :P

Amazing work Rasmus! Who is going to demo your 2 games at the Faire?

 

I haven't arranged anything. Any volunteers?

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The only problem I had was getting it to switch to the non F18A mode, via the F key. Either the program crashed afterwards, or didn't switch the mode.

Sounds like a bug. I will try it on my system.

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