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flicker free large sprites -- sample MPG


Andrew Davie

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Just wanted to address a few questions and issues, before everyone gets too excited....

 

1) To Chad -- I'm happy to share all the details and work with you on making versions of my binaries which will run on CC2. I'm not pushing the KK as a replacement, it's just something that has been readily available to me, so I use it. *NOTHING* I have done so far is "KK Exclusive", other than by circumstance.

 

2) 3E format was a happenstance, rather than an evil design trick. It's as it is, because there was 32K of RAM there and it made sense to in some way use it. Because I was familiar with 3F, 3E bankswitching became an offshoot of that. It's not a perfect design, but it is workable.

 

3) I would be happy to limit my ROMS to 480K (or 256K, even) with additional RAM represented by CC's remainder of the 512K. I'm very open to a design/limitation that will allow CC and KK to run the same files.

 

4) To those disappointed about non-Boulderdash availability...

a) I haven't written it yet. There's little to see but pretty pictures -- even if actually displayed by a binary.

b) BoulderDash is a coprighted product, and I just can't go releasing intellectual property that belongs to someone else. My plan is to develop a working prototype then put it to the owners of BD license and see what we can work out.

 

c) I'm developing an *engine* that is capable of BoulderDash-like gameplay. There's little reason that I can see why I can't release something almost but not entirely unlike Boulderdash. That's the route I will go if I can't come to a suitable arrangement with the BoulderDash license owners. But I'd like to give them a chance first.

 

d) I approached them a long time ago asking for permission to develop BoulderDash itself. They were friendly but very busy. Their terms were way too restrictive (at that time) for me to even consider developing the title. I cannot work in total secrecy with no promise that the product will ever see the light of day.

 

e) I love the game so much that I figured I'd get enjoyment from it even if I was the *only* one who ended up with a playable copy of it. But I am sure that some sort of publicly released game will eventuate -- if, of course, I finish it. Hence the title "not-Boulderdash". It might be BD, if I put a good-enough demo in their hands. But it might not... there are enough variations which are not stomping on their intellectual property that I can see it being released in some form.

 

5. Regarding "no ROM posted" -- I will be happy to post ROMs, if that is what people want. But since emulators don't support 3E mode, only people with KK will be able to view them. And since I'm one of 3 or 4 who actually currently *have* a KK... there's little point posting anything yet. I'll write to the emulator authors soon, requesting 3E support, so we can all at least see what the binaries are doing.

 

As always, I've freely shared my code, techniques, and binaries with all who ask.

 

Cheers

A

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But since emulators don't support 3E mode, only people with KK will be able to view them.

 

<a href="http://www.atariage.com/forums/viewtopic.php?t=62910">Not necessarily</a>. :-)

 

No, those are 3F demos -- without RAM usage -- current demos which use 3E (which does use extra RAM) will not work on CC or emulators. I'll try and make sure future versions are CC compatible when CC updates its support to 3E.

 

Cheers

A

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just call it emerald mines or prospector in the mazes of xor. if theres anything ive seen its that just about anybody can rip off boulderdash as long as they change the name...

 

 

so what was the first tunneling/gravity game? was it BD?

where does mr. do fit in the equation? dig dug?

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3E is just an extension to 3F. If works exactly like 3F, the only difference is, that a write to 3E switches out the current ROM bank and switches in one of 32 RAM banks. RAM access works like with Commavid RAM. Read port is lower 1K and write port is upper 1K.

 

So you get 512K Rom and 32K aditional RAM

 

If this is so, then why couldn't you have 256K of RAM inside the 3E cart without any effective changes?

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3E is just an extension to 3F. If works exactly like 3F, the only difference is, that a write to 3E switches out the current ROM bank and switches in one of 32 RAM banks. RAM access works like with Commavid RAM. Read port is lower 1K and write port is upper 1K.

 

So you get 512K Rom and 32K aditional RAM

 

If this is so, then why couldn't you have 256K of RAM inside the 3E cart without any effective changes?

 

There's no reason a 3E cart couldn't have 256K of RAM. Provided you can fit the chip onto the board, physically... no reason at all.

 

Cheers

A

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1) To Chad -- I'm happy to share all the details and work with you on making versions of my binaries which will run on CC2.

 

Hi Andrew,

 

Thanks for the spirit of cooperation. Just in case I came across that way I wasn't upset about 3E or KK exclusives. I figure a little hook never hurts to help sell something, and I'm sure Kroko has quite an investment into the KK already that he'd very much like to get back.

 

But I do think it's best for the community at large if we don't get into Format Wars, and obviously you and Kroko agree.

 

As for 3E support. I think the most natural method would be to have pages 0 - 119 be the ROM. Rather than pages 8-127. It sounds like the KK would handle this arrangement without modification. (I'm assuming that it copies the last 2K of a ROM to the last 2K of the 512K address space for both 3E and 3F.)

 

If I'm incorrect here let me know.

 

Whichever method we pick I'll try to whip up a 3E for the CC2. Care to release a 480K sample for testing?

 

Thanks again to both you and Kroko for your support,

Chad

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Whichever method we pick I'll try to whip up a 3E for the CC2.  Care to release a 480K sample for testing?

 

Here's a 480K 3E bankswitching file for you to test. This works on KK, and as you surmised it is the last 2K of the ROM that holds the reset vectors. The image shows you what you will see if your RAM is working OK. This does display a screen on Z26, but it shows data from ROM, not RAM :)

 

The code is not tidy enough to share publicly, but if you would like a private copy just let me know.

 

Cheers

A

480k.zip

post-214-1105004335_thumb.jpg

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As for 3E support. I think the most natural method would be to have pages 0 - 119 be the ROM. Rather than pages 8-127. It sounds like the KK would handle this arrangement without modification. (I'm assuming that it copies the last 2K of a ROM to the last 2K of the 512K address space for both 3E and 3F.)  

 

On the Krokodile Cart ROM and RAM are different chips. So to be compatible, the mode must be such, that writing

 

0-31 to location $003E selects RAM Bank 0 to 31 (no matter were it physically is on your RAM chip) These banks have a size of 1K.

0-239 to location $003F selects ROM Bank 0 to 239 (whereever it may be in your RAM chip) These banks have a size of 2K

 

This example is for an upper limit of 32K RAM (32RAM Banks)

For 64K RAM it would look like this

0-63 (RAM)

0-223 (ROM)

 

It is necessary that each banknumber starts at zero, because it is implemented that way. CURRENTLY the Ram banks are mirrored if you go upwards. So if you select RAM bank 32 you end in RAM bank 0 and so on.

But we really should keep higher numbers for higher banks in the future if this mode is extended to say 64 K RAM ...

 

Wouldn't it be possible to just activate a higher memory area of your RAM chip if a write to 3E takes place and enable CV access for that area ?

 

I think we should try to agree on an upper limit for RAM so that you can decide from which point upward you want to map in your RAM banks. And you need to choose a starting adress from which it is easy to map the RAM banks ...

 

I still think it makes sense to wait for the first project that is done with it and let Andrew decide how much RAM/ROM makes sense for that mode.

 

I don't hink we get problems with the fixed bank. Just let everything as it is in 3F switching. The vectors are in the last 2k of the ROM. If we keep it such, then I don't expect problems. How your hardware is dealing with the fact, that the fixed 2K bank is always the last bank of the ROM is not so important. The KK does it by always using the physical bank 255 as the fixed bank. So if you use a smaller ROM the last 2K have to be copied to that location.

 

I hope this was not too confusing :D

 

Armin

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On the Krokodile Cart  ROM and RAM are different chips. So to be compatible, the mode must be such, that writing

 

0-31 to location $003E selects RAM Bank 0 to 31 (no matter were it physically is on your RAM chip) These banks have a size of 1K.

0-239 to location $003F selects ROM Bank 0 to 239 (whereever it may be in your RAM chip) These banks have a size of 2K

 

That's what I figured, so I built it that way.

 

It is necessary that each banknumber starts at zero, because it is implemented that way. CURRENTLY the Ram banks are mirrored if you go upwards. So if you select RAM bank 32 you end in RAM bank 0 and so on.

But we really should keep higher numbers for higher banks in the future if this mode is extended to say 64 K RAM ...

Yes, mine also ignores the upper data bits so banks will wrap.

 

Wouldn't it be possible to just activate a higher memory area of your RAM chip if a write to 3E takes place and enable CV access for that area ?

 

That is what I did actually. In fact if you try to access the upper 32K of "ROM" pages, you will get them. So you could write to the RAM and then read it back in 2K chunks rather than 1K chunks. However that obviously wouldn't work on the KK, so I think programmers should not use that fact. (Just like the CC2 can't do 512K ROM + 32K RAM.) It was just too much of a hassle to bounds check the ROM bank on a wierd number like 480K.

 

I think we should try to agree on an upper limit for RAM so that you can decide from which point upward you want to map in your RAM banks. And you need to choose a starting adress from which it is easy to map the RAM banks ...

 

The reason I vote for 32K is because that is what the KK has onboard. I'm just trying to pick the least common demoninator between the two carts. That comes out to 480K of ROM and 32K of RAM. Of course someone could build a cart that has more. I'm sure the KK could be redesigned to have more RAM, just as the CC2 could. But I don't think either effort would be worthwhile.

 

Anyway, I built a 3E.BNK file, and ran Andrew's test program. I get the patten shown, although more in pink than in grey. But given the way colors works on the Atari I'm not worried about that. I'm fairly certain the matching luminance pattern indicates things are working. (I know my 7800's 2600 color pot isn't quite right actually.)

 

Currently mine only supports 480K files. Nothing bigger, nothing smaller. I may try to make it so that a startup file could copy the last 2K in the file to the last bank.

 

Chad

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Ok,

 

Startup files now exist for 3F512K and 3E to handle smaller files.  See 7800 Forum for details.

 

Chad

 

So here's a smaller file for you to test. A 128K version of work in progress. There appears to be a glitch in my code, so it's not perfect, but you should see something like the attached image.

 

Cheers

A

post-214-1105098228_thumb.jpg

notbd128k.zip

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So here's a smaller file for you to test.  A 128K version of work in progress.  There appears to be a glitch in my code, so it's not perfect, but you should see something like the attached image.

 

 

Looks to work ok. Thanks again for the test file.

 

So all you CC2 owners out there who want to get in on Andrew's latest fun have at it.

 

Chad

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So all you CC2 owners out there who want to get in on Andrew's latest fun have at it.

 

And here's even more fun...

 

This one scrolls around the large map, eating away the dirt. Use the first player joystick to move. Note the large map retains the tunnels you dig as you go from screen to screen. Awesome, or what?!

 

There's a 6MB MPG of this at http://www.atari2600.org/notbdawesome.mpg which is uploading as I type -- and which should be there soonish. Keep trying.

post-214-1105371583_thumb.jpg

notbd11jan2005b.zip

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  • 2 months later...
did the dancing baby every get released?  I'd like to check it out on my Krok Cart with KrokCom on my Mac.

834292[/snapback]

 

Attached, colour dancing baby.

Please read the readme for NTSC/PAL switching and Z26 options.

I haven't tested this on my KK, but it should work.

Cheers

A

ohno_colour.zip

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