In July 2020 I and sat down at my home-brewing desk and started to play around with tweaking my 2002 Atari 5200 homebrew, Koffi: Yellow Kopter. I have had notes about doing a 2nd Koffi game since 2002 when I finished the first one, but it seems ever more unlikely I'll devote time to do a whole new sequel with all the ideas I'd planned. So, I decided to play around with the original, add a few game play tweaks, some new visual details, fix a few bugs, and add a new 2-Player co-op mode. Some of my first changes are listed at an earlier blog entry:
As I started to experiment and add fruits, more colors, 2-Player code and other things, what it turned into was a serious need to reclaim some more ROM memory. And OH THE HORROR of some of my old code! Koffi was a 32K game, which seems like plenty of ROM for a game like this, but it fills up. And in 2002 I was new at 6502 ASM codeing and learning, so I did several routines burning more ROM memory than I needed. And I had tried to fill in all the 32K memory just for the principle of using it all, thus the original game had a lengthy Credits with people's names at Game Over. For this version, I axed all that. I reviewed several screen-drawing routines that were basically the same code, so I consolidated most of these to use tables and parameters and to call a common subroutine. Same deal with the BuildRainDrops / EraseRainDrops (which use the 5200s' missiles) - I consolidated 6 of these subroutine to be consolidated table-driven loops rather than 6 lengthy individual subroutines which all basically did 90% the same thing. Between these two categories I freed up about 700 more bytes in the past week, so that should be enough to finish 2-player mode and add some more interrupts and colors.
Here are some WIP pictures. I hope to accomplish a few more dramatic visual changes, but it depends on free memory and if adding too much logic affects the gameplay. For this version, I kept Koffi's "Koloring Book" mode, where you press the #5 key and then can use *, 0, and # keys (at the bottom of the 5200 controller) to change the colors of 16 different categories on screen. And I added 3-character text descriptions to each of the 'categories', for example CL1 is Cloud Color 1, Tr1 / Tr2/ Tr3 are Tree colors 1/2/3, and so on. In the 5200 original, it just showed the hex value 0 through F.
2 Player Mode is starting to work. You toggle it on the Title Screen by pressing the #0 key. It is understandably glitchy for now, until I modify ALL the collision and Points logic to handle 2 players. To get 2 Kopters on-screen, I took Koffi's original Player0 and Player 1 (which gave him multi colors) and devoted Player0 to the first kopter, Player1 to the 2nd.
If the first Kopter is named Koffi, then I guess the second Kopter will be named Toffi.