The MAME Action Replay Kiwi-Z Page

KIWI'S ALIVE!!!

This is where I'm going to make notes on the progress of my The New Zealand Story driver that I'm writing for MAME.

LINKS

• http://www.europe.datafellows.com/mirrors/moose/arcade_emulation_new_zealand_story.html -- Moose mentions Alan Pope's work -- broken link
• http://dspace.dial.pipex.com/thevatican/ -- Alan's KIWI-lator page -- broken link
• http://194.177.201.73/members/andrew/nzs/index.htm -- nzs Victor's Fan Page -- broken link

If you know of any others, please let me know!

REQUESTS

I need:

• Information about what the dipswitches do.
• A scan of a schematic.
• Information about how the colours work. Is there a colour PROM?

NEWS

• Didn't do anything on the driver in the last week. It seems I've done pretty much all I can do for now. I've sent the driver code to the MAME team, and hopefully somebody there will 'pick it up and run with it' as they say.

• Stole a picture from nzs Victor's site. It shows a few screen shots of how things are meant to look.

Well it's been a few days so I thought I'd update this page again. Not much has changed, really. One thing I did was get another ROM set working. The ROMs that are on nzs Victor's (http://194.177.201.73/members/andrew/nzs/index.htm -- page -- broken link) are quite different from the set that Cabbe dumped, but they're missing some graphics. The nzs Victor set do a complete checksum of all the Z80 ROMs when they start up, and it took me a while to get past this checksum, due to problems with MAME's banking. I'm probably misunderstanding how it should be used. Once I got the nzs Victor set running, the game was quite different from the Cabbe set. Now, I'm pretty crap at playing the game, and can't get past level 1-4, but up to that point the levels are different between the two ROM sets! The nzs Victor set has 'L' shaped walls on 1-1, horizontal platforms going across from a vertical support. The picture on the left is how level 1-1 starts, and the picture on the right shows the first platforms you get to, just one screenful to the right of the start screen:

That's how I remember the game from when I used to play it on the Atari ST, so I guess these ROMs are the 'proper' set. I don't really know what the Cabbe set are though - it seems unlikely that the bootleg would be so different. Maybe it's an early version of the game. As well as the levels being different, there are none of the 'snail-type' creatures that I think I remember ought to be on 1-1. In the nzs Victor set, pictured above, the baddies appear as solid white rectangles - this may be because the graphics ROMs were dumped incorrectly, so I think I need a new ROM set. Any one got the board and the ability to dump some ROMs please???

• Ported my driver to the latest MAME beta.

• Changed the graphics code to use the copyscrollbitmap() function instead of redrawing the whole background every frame. That sped it up a bit.

• Received the following information from Santeri Saarimaa:

  The levels in the Cabbe set of TNZS roms look just like the Sega
  Megadrive version (I've got the smd rom, and I just confirmed it), and
  nzs Victor says this in this "tnzs page - emulation section" page.
  
  -----
  However,note that the Mega Drive version is practically New Zealand
  Story 2. In fact,the levels are completely redesigned,completely
  new,with some new graphics,and a lot tougher than any other version.
  -----
  
  The nzs Victor set looks exactly like C64 TNZS and Amiga TNZS. Cabbe set
  looks exactly like Sega Megadrive TNZS. Original TNZS is IMO the
  nzs Victor set. So you could probably start calling Cabbe set as The New
  Zealand Story 2..
  

• Found an area in memory which gives the layout of the part of the level which can be seen at the moment. I eventually managed to get this decoded for level 1, so the background looks OK for level 1, but so far I've not discovered how the game determines which graphics bank to use in general for the background, so the 'zoo' scene at the beginning of the game and the following levels are all messed up.
  

• Still need to find out about:
  • Colours - are they on a PROM, or on the ROMs. How are they used.
  • Credits - it seems that there's a separate part of the hardware for counting credits. Need to look into this.
  • Sprite priority. Currently when Kiwi's in his balloon, the baloon obscures him. I think I might just have everything exactly backwards.
  • Sprites vanish when they get near the right hand side of the screen instead of smoothly scrolling off.
  • Using MAME's bitmapscroll() function or whatever it's called instead of redrawing the whole background every frame.
  • Sound.
  • Why the walrus is missing half his face!
  • Background graphic bank selection.

• Well, the walrus' face appeared, as if by magic, and the sprite priority was just a case of reversing the order I was drawing them. I found out how the background graphic banks are selected, too. There's a slight delay between the background graphic data being updated and the bank data being updated, so there's junk on the screen at the start of each level for half a second, but that may be because I'm using the 'working area' copy of the background graphic data, not the area that's actually used by the video hardware.

• So it's pretty much finished now, except for colours, sound, speed optimisations and a few little bits and pieces.
  

• Can anyone tell me how big the screen display is supposed to be? This is the screen as I see it when I first start a game. (Oh - and check out my high score! :o) )
  

  Is it right that half a tall tree appears just on the right hand side of the screen? Or shouldn't it appear at all until you move right a little?

• Just got back to the work - I've been lying around with a cold for a few days...

• The game is actually playable now, in that you can move around and shoot stuff... None of the background is displayed though, so it's not that playable...

• Got some idea of how the foreground sprites work. Here's how it's currently looking (ignore the junk on the top two lines - that can be removed later). The scanner is still messed up, but... I'll get to that later.
  

• Sorted the other half of the foreground graphics. The colours look a little better, but that's just from reversing the order the graphics ROMs are loaded into memory:

• After asking around the MAME team, I discovered that Martin Scragg had already made a start on a driver for the game. He sent me what he had already done, lots of which matched what I had done (nice, that :o). He also had made a start on the 2nd CPU, which I hadn't yet, so I added that and everything stopped working. Then I spent a few hours getting back to how things were before adding Martin's code, only now both CPU's are emulated. The new CPU (also a Z80) handles the reading of the inputs (stick, buttons, coins, etc) among other stuff (like maybe driving the sound chip?) and communicates with the main CPU via an area of shared RAM.

• Found that what was holding me up was something to do with MAME's paging of memory. The TNZS machine uses paged RAM, which MAME didn't seem to be handling at all well - it was overwriting the shared RAM buffer when it should have been writing to paged RAM.

• OK, so there's not much to see yet. But the test mode seems to start up OK...
  

• Ha. I just noticed - it's upside-down! The title's at the bottom...
  

  That's better. :o)

• OK, so it's taken a couple of hours, but I've got most of the inputs mapped now. I don't know what the dipswitches are, but it appears one mirrors the screen, and one sets whether to show the export warning, because now instead of test mode I'm getting a backwards warning screen.
  

• It's beginning to dawn on me that if this game is ever going to get any better, then I ought to start drawing some graphics and stuff... Just words and scores doesn't cut it. So here's some scores and stuff...
  

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