Birthdays, weddings, aniversaries, work, and Runescape are all conspiring against my efforts to complete this game. But there is forward progress, as I'm determined to have this done in time for the 2006 Minicomp. This post combines the last 4 updates to the code, with several new features.

New Features:

V0.12:

- Added preliminary score display.

V0.13:

- Completed programable 7 digit score display with 1 digit reinforcements display.

v0.14:

- Expanded the ship rotation graphics to use 16 positions instead of 8. Thanks to Nathan Strum for providing the ship animation cells.

- Moved ship graphics into its own file to simplify automated changes.

v0.15:

- Updated player shots to shoot in all 16 directions.

- Implemented 16-bit physics for player shots.

- Added offset to player shot initialization so the shot appears to come from the center of the ship.

- Fixed bug in ball size. The ball size bits in CTRPLF were being overwritten when playfield mirroring was disabled during score display.

Todo:

- Add more sounds.

- Implement player shot to shield collision detection.

Known Issues:

- I finally understand the purpose of vertical delay. I'll add this to the kernel so full vertical resolution can be restored. The game currently uses half vertical resolution.

- The ricochet physics is still off.

Development Notes:

I spent several hours writing a perl program that translates 5 animation cells into 16 Atari bitmaps, split into odd and even scanline tables. This was some hairy code. I'll post it when I get more time.

I'm really happy with how the score display came out. In its original implementation, I was using a 25-byte RAM buffer, and requiring 1500 cycles per frame to preload. After several rounds of optimization, I got it down to 12 bytes of RAM, and it loads real-time in the kernel. I'll post some code examples later.

This dynamic score display is a deviation from the original game. The original game only displayed the score when the player was killed or the Star Castle was destroyed. If I'm going to have code to display the score, there's no reason not to display it during the game, other than the small hit to screen realestate.