EricBall's Tech Projects

Juggle bank usage is fun - not. I'm at that stage in MM

Juggle bank usage is fun - not. I'm at that stage in MM

I think I'm through most of that. SuperCharger puts some additional restrictions on bankswitching in that there are 3x2K SC-RAM plus the 2K SC BIOS ROM, but you can't select all possible combinations.

 

Bankswitch layout is really a matter of what needs access to what. In Leprechaun I've got 5 pages for level & sprite data. So that's gotta be accessible by the kernel, the routines which scan the level data for movement, and the routines which update the level data. But the 6-digit routine doesn't need access to that data, but has a page worth of character sprites. So that's all stuck in a different bank which can also access the BIOS, so that's where the title and other screens will go.

 

Of course, standard 2600 bankswitching which swaps out all 4K has bigger challenges since you're looking for routines which don't need access to any large shared data, and where the bankswitch overhead & address overlay can be made to work.

Bankswitch layout is really a matter of what needs access to what. In Leprechaun I've got 5 pages for level & sprite data. So that's gotta be accessible by the kernel, the routines which scan the level data for movement, and the routines which update the level data. But the 6-digit routine doesn't need access to that data, but has a page worth of character sprites. So that's all stuck in a different bank which can also access the BIOS, so that's where the title and other screens will go.

 

Have you given any thought to using an AtariVox/MemCard to hold level data? You could have one program which puts 4K of level data into the memcard at $3000-$3FFF (the scratchpad zone) and then have the main program load levels from there.

Have you given any thought to using an AtariVox/MemCard to hold level data? You could have one program which puts 4K of level data into the memcard at $3000-$3FFF (the scratchpad zone) and then have the main program load levels from there.

Supporting the MemCard for high-scores is on the wish list, but I'm not sure I understand what your suggestion is or what value it has over the existing Online Level Editor.

Have you given any thought to using an AtariVox/MemCard to hold level data? You could have one program which puts 4K of level data into the memcard at $3000-$3FFF (the scratchpad zone) and then have the main program load levels from there.

Supporting the MemCard for high-scores is on the wish list, but I'm not sure I understand what your suggestion is or what value it has over the existing Online Level Editor.

 

The idea would be that the user would load the game in two parts. Part 1 would put 4K worth of level data into the AtariVox and then load Part 2, which would be the game itself. The game could then switch among 4K worth of levels without having to reload anything. Basically, it would be functionally equivalent in many ways to having 10K instead of 6K on the SuperCharger.

I would think if you did something like that, you'd have to include a MemCard with the game, and bump up the cost of the game to cover it, right?

I would think if you did something like that, you'd have to include a MemCard with the game, and bump up the cost of the game to cover it, right?

 

You could offer people the choice of either using a memcard and doing a two-part load after which no more loading would be needed, or else loading each level off tape/CD. The memcard wouldn't be absolutely required, but it would its presence would make the game much more convenient.

You could offer people the choice of either using a memcard and doing a two-part load after which no more loading would be needed, or else loading each level off tape/CD. The memcard wouldn't be absolutely required, but it would its presence would make the game much more convenient.

Except each level is ~768 bytes (3 pages, spread over 5 pages in SC-RAM), so 4K would only be 5 levels (versus 99 on tape/CD).

Except each level is ~768 bytes (3 pages, spread over 5 pages in SC-RAM), so 4K would only be 5 levels (versus 99 on tape/CD).

 

Each level is 19x32 cells each of which holds one of six things. I can understand that during gameplay you may need to have a lot of data "fully unpacked" for use by the kernel, but by my tally each level should take under 256 bytes (19x3x4 plus a few for monster placement) without compressing anything very 'hard'. Using simple arithmetic coding (3 pixels/byte) would reduce that to 203 bytes plus monsters; using fancier packing (16 pixels/5 bytes) would reduce it to 190 plus monsters. So 4K would allow for 16-20 levels, which would be enough for a reasonable game.