TROGDOR
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Posts posted by TROGDOR
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Hi AlmightyGuru. I'm somewhat familiar with the SID chip, having done some programming for it with the Commodore many years ago. I also did a little wikipedia research on the SID file format.
I'm not aware of any atari 2600 sound file format, other than running a binary ROM in an atari emulator. It seems quite possible that atari music could be translated into midi format by replicating the unusual atari frequency tables and the various wave tables. But what you're really asking for here is a TIA (Television Interface Adapter) sound format, which is the chip responsible for producing the Atari's sound effects.
Atari music is dependent on the TIA chip and the ROM implementation that generates the TIA input stream. I would guess the easiest way to accurately capture the resulting music/sounds from a binary would be to add a TIA recording feature to an existing emulator such as Stella, and then write out the sound file in either midi format, or some new atari TIA format.
Of course, music can be saved today by capturing sound directly from an emulator application into a wav file. But an atari specific format, or midi, would be more concise.
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Man, that's just crude.
The fish may be alive, but at least they're upsidedown!
Yes, yes... keep the puns flowing!
The fish are upsidedown. Just like the BP shareholders.
Nice pic Devin. I tip my Top Hat to you.
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Yesterday some LDY SED I was an ASL just BCS I used my BRKs for a SEC, AND I CLD have ROLed my car! What a LSR.
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I'd be happy with just Moon Cresta. (and have contemplated doing it myself.)
TRIP TO THE SPACE WAR
MOON CRESTA
WRITE IT NOW !!
YOU CAN GET A LOT
OF FUN AND THRILL -
Here's a post that discusses random number generators, and techniques to seed them. I recommend the 16-bit implementation. It's the best trade off between RAM usage, speed, and getting a reasonably random number sequence.
It's much easier to generate random numbers that are multiples of 2. To get a number from 1 to 6, you could generate a number from 0 to 7. If the result is 6 or 7, get a new number until you get one that is less than 6. Then add one to the result. The only risk with this technique is that it requires an indeterminate number of cycles, since you don't know how many 6s and 7s you'll generate before you get a usable number. It's better to adjust the game requirements so that only powers of two are needed for random numbers.
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To understand how negative numbers work in binary, you need to take a look at one's complement and two's complement math. You'll find information about it here, and other tutorials from Googling.
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BTW: Any opinion about my "decision" post above?
I didn't notice much visual difference between the two modes for the Gecko. I'd say remove it and reclaim the cycles and archive the more accurate perspective as a code thread.
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It's no problem. I've moved on to another ambitious experiment. I'll be posting it soon, probably this weekend.
Since I have no imminent plans to turn this into a full fledged games, I will share the finished engine code with anyone interested.
I will likely take you up on that at some point. I've had a game in mind for quite some time that I was debating whether to implement in 2D or 3D. That's what started me on the Elite research.
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Excellent work Thomas. I have to admit I'm a little bummed. You've already implemented what I had hoped to achieve. Still, it's nice to see a clear demonstration that this technology is possible on the 2600. Hopefully we'll see some 3D vector games spawned from this engine.
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Very impressive Curt, great work!
I have a few questions about the designs:
- What technology node sizes were the chips designed for? (I'm guessing around 2-micron.)
- How many layers are the designs?
- Have you been able to compute any transistor counts?
- What are the file sizes of the gds?
- Is the logic full custom? I can see what appear to be two memories in the center of the GTIA layout, unless those are gate arrays.
- Who owns the rights to the gds?
With the full schematics and layouts, it should be possible to perfectly emulate these chips down to the most minute details.
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All the more reason to watch for copyright police. Disney can be picky so if anyone successfully develop a good working 2600 version, they'd have to be released under name that won't upset those big eared lawyers.
That's why the work I'm doing is based on Atari's Surround, and it won't be called Tron.
Do you all think that Disney would be willing to license the character for a limited release 2600 game?
Very doubtful. First Star Software, the owners of Boulder Dash, is a small company, and the fact that they allowed a port of their game is the exception to the rule. Disney is a massive company with 150,000 employees. They have a reputation for being very aggressive about copyright enforcement.
For details, see this public service announcement:
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Tron?
Never heard of it.
But I have been working on a totally unrelated game called Positron: Write Cycles, which is in no way similar to the licensed Disney franchise. My game is loosely based on the early Atari game Surround. Or Snafu, for Intellivision fans out there. The game is posted in my blog if you want to check it out.
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Most of my asm files use an 8K footprint now, and I keep running into a problem in the Stella debugger of setting a break address, and having it hit on the wrong bank. Is there an easy way to specify the bank when assigning a break?
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I haven't even played it yet, and this game already kicked my ass.
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Regarding the images, I'm viewing the page on a notebook running at 1280 x 800 resolution. If I maximize the browser window and reload the blog page, I get the blue tab "Resized to 100% (was 638 x 395)," so as you mentioned, it looks like some kind of tweak will be necessary to prevent this.
Hmm, that's the same resolution I was using as well (on a MacBook). It doesn't seem that you should see the "Resized to 100%" bar if the image is actually at 100%. What web browser are you using?
Thanks,
..Al
Sorry, I just noticed your reply. I'm using Firefox 3.5.3 on Windows XP SP3. Below is a screenshot that I just made a few minutes ago. The browser window in the screenshot is 1298x1018, but the image still isn't shown full size.
Another issue I noticed is the automatic tag links in my blog, such as this one, all go to an empty page that simply says "TROGBlog has no entries yet." If you click on the link, you'll see what I'm referring to.
I'd recommend a slightly more distinct color difference for links in posts. The difference between the blue text and the black text in the sentence above is barely noticeable.
Thanks for you help with this. I'm sure it must be a real pain having to fix all this stuff.
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Nice work Adamantyr. The title screen looks great. I poked around on your site, and the game looks like it's coming along nicely. The map screens reminded me of Questron for the C64.
You won't have to worry about people asking "why in assembly" or "why a vintage system" here.
I had a friend with a TI99 back in grade school, so I've spent many hours on this machine. The TI99's potential as a gaming system was never even remotely realized. It's always good to see more development on this system, particularly in assembly.
My favorite game for the system was definitely Hunt the Wumpus, so much so that I made a port of it to the Atari 2600. There is still work to be done for that game, but it's playable.
Good luck on your project.
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Hi Al,
The blog view counter appears to be broken. I got about 40 new views on Sunday, and then none since then. It's more obvious with the new GideonsDad's Blog post, which still says 0 views six hours after it was posted. I looked at it, so the count should at least be one.
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Great! Thanks for the help Al. Changing over to the flash uploader interface resolved my problems. After enabling the flash uploader, I now see "Add to Post" and "Delete" options for each of the attachments, and I removed the redundant attachments.
Regarding the images, I'm viewing the page on a notebook running at 1280 x 800 resolution. If I maximize the browser window and reload the blog page, I get the blue tab "Resized to 100% (was 638 x 395)," so as you mentioned, it looks like some kind of tweak will be necessary to prevent this.
Thanks again for your help.
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Last night I was working on a new entry for my blog, and I'm having trouble adding an attached zip file. When I use the upload interface, it loads for a couple seconds, then just says "Done" in the status down in the bottom left corner of the browser, but doesn't say anything else in the web interface. Because of this, I tried several times to upload the attachment.
I posted the entry in draft mode, and now I see 3 duplicates of the same file in the Attached File(s) section. I don't see a way to delete the two extra copies.
When I go to "Manage Attachments" in my profile, I don't see the newly uploaded attachments in the list.
In the blog editing interface, I don't see any way to insert a link/reference to the attached file inside the post after it's uploaded.
Any help with this from Al or other mods/users is appreciated. I'm using Firefox version 3.5.2 under Windows XP SP3.
TIA (Thanks in Advance)
One more question. A screenshot I included in my blog at size 638 x 395 was automatically reduced, so that another click is required to view at full size. What is the cut off size to prevent this size reduction? 640 x 400 seems like a reasonable upper limit for screenshots, since this is the default 2x size from the Stella emulator, and it's the same size I've been using for 3 years of blog posts (I'd rather not have to go back and resize them all.) Is there a way for me to configure this limit in my preferences, or is this a global limit for the site?
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I'm curious what is everyone's favorite 6502 instruction reference to use when they're coding. I've been using this one for years and have been very happy with it. It has pretty much everything, except illegal instructions. But I'm wondering if there are any better options out there...
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Also, you need to be aware that there's a small delay when writing to the playfield registers, so you must complete the write a few cycles earlier than you'd otherwise expect-- I can't recall the exact number, I think it's something like 1.67 or 2.67. (Yes, it's an oddball number, perhaps because the playfield counter is updated once every four color clocks, instead of once every three color clocks like the ratio of CPU cycles to color clocks.) I made some tables and had posted them to the Stella mailing list. I'll dig them up tonight and post them here. But also beware that some "compatible" machines seem to require an extra little bit, probably because they use "back-engineered ripoffs" of the TIA instead of a "real" TIA.
Michael
How does the Stella emulator handle the playfield delay? I often use mirrored mode for asynchronous playfield display, which is particularly picky for the center PF2 to PF2 transition. Only a PF2 store that completes at the end of cycle 48 will work. One cycle earlier or later will result in mangled graphics for either the first or second PF2 display.
How common are the ripoff machines?
I'm having trouble saving that timing image with the new forum interface. When the attachment loads up in my browser, right clicking doesn't provide the usual "Save image as" option. It only allows a save page option. I'm using Firefox 3.5.2.
TIA (Thanks in Advance)
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Here's something I should have done ages ago. It's a simple text diagram showing the timing of every pixel on the screen. This makes timing calculations for an async playfield much easier.
2222222222222222222222333333333333333333333333333333444444444444444444444444444444555555555555555555555555555555666666666666666666666666666666777777777777777777 2333444555666777888999000111222333444555666777888999000111222333444555666777888999000111222333444555666777888999000111222333444555666777888999000111222333444555 ................................................................................................................................................................ 6036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036036
4444555566667777777766665555444433332222111100000000111122223333444455556666777777776666555544443333222211110000000011112222333344445555666677777777666655554444
000000001111111122222222333333334444444455555555
The first 4 rows are a vertically written number. For example, the first number is 22.6, and the last number is 75.6. These numbers are the fractional scanline cycle count at the time each pixel is displayed. There are 160 numbers, corresponding to the 160 pixels of the visible screen.
The next row shows all the blocks of the playfield using a mirrored configuration. (PF0 PF1 PF2 PF2 PF1 PF0)
The last row is a 6 sprite display, which you can move around as needed.
From this diagram, it is clear that the STA PF2 must start at cycle 46 and end at cycle 48 to perfectly synchronize with a reflected playfield. This has been useful for determining exact timing for the other playfield stores as well.
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I rented a VirtualBoy system back in 1995 when it came out. I played it for 4 hours. It gave me the worst headache of my entire life, so bad that I had to miss work the next day. The problem with the system was the focus point felt like it was only 4 inches from your face. Try holding your hand 4 inches from your face and focusing on it. For me, that's painful, and I have 20/20 vision.
On a modern LCD shutter system, hopefully the simulated depth perception isn't as painful.
That said, it's cool you're writing a game for this system. The more obscure the system is, the more it needs game writers. And with only 770k systems produced in its short life, the VB is one of the more obscure systems out there.
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Oh, I forgot to mention, happy solstice!
In stranger eons, death may die.
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The Last Door
in Classic Console Discussion
Posted · Edited by TROGDOR
Hey folks,
It's been about 5 years since I logged in, but I wanted to stop by and put a plug in for a game that I recently discovered that should resonate quite nicely with the AtariAge community. The game is called The Last Door. It's an incredibly pixelated Lovecraft-style graphic adventure. My wife and I played it for about an hour tonight, and so far we love it. Although the graphics are very low res, the sound effects and music are normal fidelity, and add a lot to the game. The game does an excellent job of building suspense. It's free-to-play with a donation system for people that want to contribute. I highly recommend you give it a try at www.thelastdoor.com. Some screenshots are included below. Enjoy!
-TROGDOR
(I put this under classic gaming because although it is technically a modern game, it's not exactly your typical XBOX / PS fare.)