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Jetboot Jack

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Posts posted by Jetboot Jack

  1. Posted

    Dan,

     

    I was refering to the Shamus sprites 2X2 antic 4 characters - the routine to move these would need just 6 chars to achieve all direction smooth moving - albeit on complete characeter cell (for 4 - horizontal - or 8 - vertical - pixel movement cycles) boundaries and no diagonals.

     

    12 characters is what I used in routines for a 16 X 16 object with the same restrictions as Shamus. A 16 X 16 with diagonal movement too requires just 15 cells.

     

    The upside is you can have LOADS of sprites all moving for the cost of rotating the data once! And as most games of that era have waves of enemies you really only need to use 30 or so characters to provide awesome looking attack waves..

     

    When Harelequin did Menace (I WILL release the demos as soon as I can - HEAVEN - BTW your vertical overscan scroller - didja release any demos with it?) we overcame 2 more problems:

     

    A parallax overlapping scrolling playfield (2 layer, with large irregular objects in the foreground) and character sprites moving atop this, and fully masked in the dual layer scroller, plus bullets and missiles in chars too - all Antic 4 again and it looked pretty good, especially with a BIG colorful pmg player ship - well we had to use the Hardware sprites for something!.

     

    We also did some demo routines to allow the char mode sprites to overlap - that used LOADS more characters, but looked great!

     

    sTeVE

  2. Posted

    Dan - you should see the Menace (take a look ath the AMIGA version) code we wrote! A scrolling Antic 4 screen, with a parallax backdrop - rotated character data - so two overlapping scrolling screens in effect.

     

    PLUS 10 16*16 pixel character mode sprites moving in 1 pixel increments for the enemies!

     

    We used the same basic backdrop code from an earlier game - CONTAGION - albeit in a very simple version to get the 2 layer parallax on that game. Or take a look the BIG tank at the end of the levels in PLASTRON - the team scrolled the tank on, but rotated the character data to look as if the background was still while the tank rolled on.

     

    Bill - the Shamus sprites move at 1 pixel increments not 4! The data is rotated thru the characters - that's the way I've done it in the past - with either 10 characters each at different data offsets or copying the data into a block of 6 characters or so you can get 100% smooth motion!!

     

    sTeVE

  3. Posted

    Bill,

     

    In Shamus the enemies do move smoothly - looks like multiple redefined images to give pixel increment movements.

     

    If you look at the colors the enemies and the backgrounds are all the same ones.

     

    It may be Mode E, but I can't see how you can animate the walls in that mode, it looks like character set rotation for animation for all objects.

     

    Pickups and Shamus are PMG...

     

    sTeVE

  4. Posted

    Bill - Shamus uses software sprites -- its either a bit mapped, or more likely a character based game since it has a black background, the enemy never overlap and always move in block wide horizontal and vertical steps (and with those VERY animated deadly walls too much data to shunt around a bitmap IMHO!).

     

    Calamari - WOW uses software sprites too -- Mode 7 I reckon -- there is an antic E resolution line where the name of the level is -- looks like mode 1 text, and I wonder if the warriors are PMG...

     

    sTeVE

     

    [ 01-14-2002: Message edited by: Jet Boot Jack ]

  5. Posted

    Cafeman,

     

    Nasty Tip - If you rip the a cart from an 800XL while on and running you will corrupt the background graphics, but the sprites will stay in place - hehehe - I learned that as a very young hacker...

     

    Also a friend disassembled the ROM data from a disc dump of Popeye, many, many years ago and we looked at some graphic data -- we saw the sprites :-)

     

    You don't have to put a DLI on every mode line - Miner 2049'er does 3 -- see their page.

     

    Like Dan has pointed out -- I would dynamically poistion the DLI as vertical re-use and horizontal positioning is required.

     

    Almost every Atari 8bit game uses vertical sprite re-use in some form or other. Vertical re-use is not multiplexing - since no two instannces of the same player occupy the same horizontal line.

     

    In Joust they simply flicker the birds, placing sprites every other frame, when more than 4 occupy a horizontal line. I would imagine that Joust uses a very dynamic sprite kernal - as it only has a DLI at the start of the display and stuffs horizontal position data changes in to HPOS via a vertical counter.

     

    Horizontal multiplexing to get more than 5 PMG per line is possible in many ways - I have written code that does that by drawing all sprites to be multiplexed every other frame - so all sprites except the main character shimmer. I've also written a routine (DLI's at fixed vertical positions) that only shimmers PMG that occupy the same horizontal line, checking transitions from one vertical screen zone to another.

     

    One other technique exists and I have made it work - albeit in a non commercial game application - just a test bed. Using a horizontal timing kernal I have got 8 animated and moving sprites on a horizontal line with no flicker! The code was SUPER tight, precise instruction timing like a 2600 screen kernal.

     

    sTeVE

     

    P.S. I get Popeye to run in Atari800win under 2K and XP just fine BTW

  7. Posted

    You're right Popeye is in char mode - the Sea Hag's thrown bottles move in character increments.

     

    The hearts/notes/letter in Popeye are Missiles - each is 4 pixels wide - 2 missiles per object - watch and you'll never see more than 2 falling objects on a line, when they hit the water theu become antic 4 characters...

     

    Miner's enemies are on seperate mode lines - no need for DLI's every scanline - just on those modelines that need seperate horizontal positions for the players.

     

    Can you expand more on your multiple sprite per line query - I've written a horizontal multiplexer in the past...

     

    sTeVE

     

    [ 01-13-2002: Message edited by: Jet Boot Jack ]

  8. Posted

    So "Glenn the 5200 man" was just another Pirate - he didn't code games, just ripped them off - ho hum!

     

    I always hated that tag line:

     

    "Glenn the 5200 man presents XXX another unreleased game due to the mismanagement at Atari"

     

    What an arrogant idiot - did he ever think that like Donkey Kong some titles were liscenced for Console and not Computer and the other way aroubnd?

     

    And so what if Atari didn't release the titles - nice though they are too see in an historical sense, it was up to Atari!!!

     

    Most got lost in the sell off from Warner to Jack - he simply wanted to get on with the ST and the new stuff, not plow more money into a fading video game system.

     

    Lets face it the 5200 sucked, the 7800 was much cooler, but totally overshadowed by the power of the NES and SMS - when it eventually came out (now that was a dumb call to even bother releasing it!)...

     

    A 5200 to 8bit conversion is pretty simple - infact some of the games he claims to have cracked were coded as both 8bit and 5200 version - Kangaroo, Crystal Castles, Super Pacman...

     

    sTeVE

  9. Posted

    Well, I would never say my contributions made an impact on theh Atari World, but I did some Atari stuff in various roles:

     

    Released On 8bit:

     

    Zero War (urgh!) - Atlantis (I think)

    Plastron - Harlequin

    Contagion - Atari

    Z-Force (double urgh!) - Atari

     

    Unreleased On 8bit:

     

    Menace - Harlequin

    Last Ninja II - Harlequin

    Shadow of the Beast - Harlequin

    Project Xanthien - Harlequin

    Pacland - Atari

     

    Unreleased on ST:

     

    Paintz - Atari

     

    Then I got my first real job in the games industry at Microprose :-) and worked on loads of games (Gunship 2K, X-Com series etc)....

     

    sTeVE

  10. Posted

    I have a fresh install, not an upgrade from 2K etc, of XP Home.

     

    My system is a P4 1.8Ghz with 512Mb Ram.

     

    Z26, PCAE, Stella, Mess (5200/7800, Coleco and NES), Atari800Win+, Magic Engine, Xformer, Handy, VMSX and Vcoleco all work 100% under XP. All without any tweaks to compatibility settings.

     

    Z26 works at a fine speed too.

     

    I moved everything over from my laptop that runs 2K pro - where everything was cool too...

     

    sTeVE

  12. Posted

    Well I have to say I find MESS pretty straight forward to use, especially given it is emulating a TON of systems, not just one.

     

    Simply place a valid OS ROM in the "bios" directory. The directory name is indicated by mess - the second column - and named the same as the directory - a7800/a7800.rom.

     

    Put the games anywhere you like and then right click on the system name Atari 7800, select properties and open the "software" tab - browse to the directory with ya roms in and bingo!!!

     

    Works every time for me...

     

    sTeVE

  14. Posted

    I redrew the LN2 art based on the C64/ST data, in OCP...

     

    Beast I used OCP on the ST to mash the Amiga graphics to 160 pixel screens, then ripped that into 8X8 elemnents which were heavily reworked then squirted it all down to the XE and reworked/retouched in a character editor.

     

    The other titles (Pacland, Menace for instance) I did all original intpretations from the Arcade/Amiga.

     

    sTeVE

  16. Posted

    You mean kinda like the way Stella lives and the cuttle cart work for 2600?

     

    I've never seen such a system - I guess the 2600 stuff went that way because of the Supercharger.

     

    8bit ROMS are binary dumps of the data - .bin or .rom files you load in.

     

    sTeVE

     

    [ 12-14-2001: Message edited by: Jet Boot Jack ]

  17. Posted

    We used DLIs to put multiple character sets on screen and vertically alter color palettes. Any one line only has 5 character colours, but each mode line can have a couple of those colors changed...

     

    Also for some areas we used enlarged PMG masked by characters to create other color zones.

     

    sTeVE

  18. Posted

    Beast - we did that in Antic4 - for the exterior areas we used 2 character sets - sky, and foreground - all enemies were sprite based.

     

    Interiors we used one character set per area, with 4 versions for animation. The enemies were a mix of characeter and sprite objects. We split the screen into 4 areas and scrolled them independently when needed for large enemies or groups of enemies.

     

    Last Ninja - once again many character sets - so each screen had the same detail as the C64 version. The sprites were simple - 16 pixel wide monochrome - he's just a black ninja after all! the priority masking was handled just as the C64 version - loads of character data shaped masks in ram that get overlaid into the sprite data with a boolean (AND I think) to create the illusion he's going behind objects....

     

    The data will be available soon - I'm moving to San Jose in Jan - so I can unpack then!!

     

    sTeVE

  19. Posted

    That seems a bit of an odd position - "Anything else and I might as well be using an emulator."

     

    One would hardly describe a 7800 running a 2600 game as an emultor - there is no emulation, the code is running on the correct CPU etc....

     

    Most games are designed for not just one system, but the one that will get the compnay the most revenue.

     

    And as for playtesting - you only had to work for Atari to know what a complete joke that is, people like Nintendo/Sony etc have huge QA depts, Atari got the warehouse staff to test the games!!!!

     

    sTeVE

  20. Posted

    I guess not....

     

    Glenn - if ya really wanted to play those games with audio tracks (like Moonbase Io) your best bet is a real Atari!!!

     

    I would guess the best solution would be for an emulator to be able to load a WAV of a tape...

     

    sTeVE

  22. Posted

    I'm not saying ANTIC E is not a great mode - it is, and the 8bit can shift software sprirtes with the best of them (far better than the C64 could manage).

     

    But unless there is a compelling reason to use this high RAM mode I'd say that the character modes really give you the best tradeoff (All the games I've ever done on the XE including Shadow of the Beast and Last Ninja II used Antic 4).

     

    As for the software sprite kernal Baker describes - its nothing like a DLI - 'cos the 6502 is doing all the work!!! The beauty of the 8bit architecture is the independence of ANTIC and the 6502, not slaving the 6502 to the screen draw allows such possibilities. However you can use the 6502 to do everything if you really want

     

    With the spare 6502 time you can always use it to do complex character color kernals, or spiffy audio etc

     

    Vertical sprite re-use with DLI's is the "cheapest" way to get loads of independent objects running around - almost the only way you're gonna get 60fps!

     

    sTeVE

     

    [ 12-11-2001: Message edited by: Jet Boot Jack ]

  23. Posted

    I assume you have other NTSC toys that work just fine?

     

    There are two NTSC standards in Europe on TV's - 3.58 and 4.X (I'm afraid I forget the exact value) - the 4.X carrier frequncy TV's cannot accept true North American NTSC signals - sound problems being one symptom...

     

    sTeVE

  24. Posted

    hhmmm...

     

    Neither game does much complex DLI work -

     

    Defender is 4 colors and software sprties galore - no real DLI work there.

     

    Joust will be using a DLI for the vertical sprite multiplexer, but its not a complex one.

     

    Seems a waste of RAM to me

     

    sTeVE

  25. Posted

    Well there you go - I assumed these games were done in character mode - no need to be in bitmapped modes - Joust especially (unless the vultures are not all done with players) - my assumption.

     

    Id the DL all mode E lines - or does it start mode E and then change modes - simply to declare enuff RAM?

     

    What is done in Joust with Bitmapped FX?

     

    Defender looks like it could be either way - no compelling reason for it to be bitmapped - I guess looking at Stargate its logical to be bitmapped - same code base I guess..

     

    sTeVE

     

    [ 12-10-2001: Message edited by: Jet Boot Jack ]

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