Journey to the Planets port

[Wrathchild]

On this A8 thread I mentioned I'd begun looking at porting this title to the 5200. A while back, Steve/Classics had told me that it would be a good title to attempt and also I was impressed with fandal's port of Galactic Chase.

 

Anyhow, despite being away from home and not having my normal development machine/environment I've made some progress on this and so hope over the next few weeks to provide something usuable here. The original 16K game will probably need a 32K cart base although it will use very little of the other 16K.

 

The A8 original uses pretty much all of the zero-page and so for the 5200 those located in the 'registers' have had to be relocated. This appears to have gone OK, moving them to the bottom of the stack. The downside of this is that where a load/store to one of these locations would have taken 2 bytes it now takes 3 and so this shuffles the existing code around bit and so this needs to be worked around to get the 5200 version working correctly. Hence to do this a few areas of code were moved to the other 16K along with the replacement key/stick routines.

 

The second issue is that quite a chunk of the coding it table driven and these contain offsets to routines and data in the original 16K ROM. Therefore I've tried to keep these areas in their original places and, again, this looks to have paid off. When I'm back home (as I'll be driving the family back from the Czech Republic to the UK tomorrow) I may write a quick program to output better source from the original which correctly labels the offsets which should mean they can be relocated if required.

 

As it stands now, yesterday I began trying to integrate a joystick replacement routine but this seems to have regressed some other areas, mostly on the title screen which previously showed the ship and had the man walk to it and fly up (albeit that the man's colours were wrong). Now, the ship appears - but when the man is supposed to appear, the game starts instead and so I'd like to fix this up before releasing anything.

 

I'm using Atari800WinPLus 4 for 5200 emulation as I can compare trace debugging of the 5200 versus the A8's execution. However the POT and CONSOL emulation seems a little odd so I may also use another emulator to see if this helps.

 

Stay tuned & Happy New Year!

 

Mark

[Wrathchild]

OK, had a chance to resume this today after coming back to the UK only to be snowed in.

 

After a day of hair pulling and frustrations trying to understand why my keyboard routine wasn't kicking in (when all it turned out to be was a SEI!) I think I have something working reasonably enough, although of course it needs some play testing both under emulation and the real thing (which of course I don't have ).

 

Things to do:

On my PC the '-' key (next to zero) causes the game to suspend - is that the correct key on the 5200?

Also I'll need to change the text of the message from 'press option to resume' to 'press pause' I guess?

Fix anything you find.

 

Regards,

Mark

j2p_5200_rel1.zip

[classics]

Superb work! I remember looking at the disassembly for this and thinking it would be a huge PITA to convert. :-)

 

Steve

[bohoki]

any chance you gonna look over rampage and see what you can do?

[Kernal]

good job so far..

I like it.. i was wondering if theres any way we can spruce up the graphics a little...

 

Also... still cant get in the ship with the gun or without the gun.

 

I like it though =)

[Wrathchild]

For the gun, once you've walked into it then it will disappear but the man's arms now point diagonally up. You then return to the ship and when you are over it simply press 'fire' and you enter the ship and can fly off.

 

Graphics would be another kettle of fish. As with there other titles, the puzzles are often carefully planned to the precise pixel. There was talk on one of the A8 threads of doing a remake of this game, this work could be used as a base for that.

[Wrathchild]

PITA... yes! But nibbling at it a bit at a time paid off.

 

A bit I'd initially missed was located during the initialization. There is a table driven section which reads a sequence of 5 byte sets, the first byte being a length and the remainder being word pairs for the source and destination addresses for a copy-to. This sets up quite a few things like sprite colours. So many of the sources for these needed remapping but also one destination due to the re-location of some of the zero-page data.

 

Regarding Rampage, that uses memory above the top of the 16K the 5200 has, however there appears to be a big block of unused RAM ($800-$1B00) and so potential for relocating things is there, but would be quite an undertaking I think. However if doing so also means others can work on a VBXE enhanced version for the A8 then I might give this a stab.

 

Mark

[jum]

Nicely done! Your effort is much appreciated.

 

I have just tested it on Jum52 emulator (v1.0 and v1.1), seems to work OK although there is some wierdness trying to leave the title screen after picking up the gun and getting into the ship.

 

- Jum

[+Allan]

Thanks Wrathchild,

Nice conversion. That weirdness is also in the original 8-bit version although the 5200 version does it a little longer. After that it seems to be fine.

 

Allan

[+Allan]

Here's a label for Journey To The Planets for making a cart. Any comments are welcome.

 

Allan

5200_Journey_To_The_Planets.jpg.zip

[Wrathchild]

Hi Jum, thanks for testing. I think the weirdness you refer to is on the title screen, as the ship flies up, you get some colour jitters at a couple of points. Like Allan said, I'd referred back to the A8 version when developing to ensure it happens there too.

 

Allan, nice label! With Classics help I've switched off the Atari logo upon power-on - didn't see why they would get credit - so that may apply to the label too, i.e. remove the © Atari line?

 

Not being that familar with the 5200, what is the common convention for use of the logo screen?

 

Regards,

Mark

Edited January 15, 2010 by Wrathchild

[+Allan]

Allan, nice label! With Classics help I've switched off the Atari logo upon power-on - didn't see why they would get credit - so that may apply to the label too, i.e. remove the © Atari line?

 

Not being that familar with the 5200, what is the common convention for use of the logo screen?

 

Regards,

Mark

I can make a Roklan only label without the Atari style. I just have to find a better scan. Hopefully I can find the ad in Compute or similar magazine.

 

As far as the logo screen goes, Atari used in all their games and everyone else just bypassed it.

 

Allan

[+Allan]

I updated the label in the previous post. It's got a much better scan thanks to Video Game Addict and I changed the text to Roklan Corp.

 

Allan