Superchip Scrolling Multicolor Rainbow Fuji

[SeaGtGruff]

Here's a silly-but-groovy program that I just wrote to display the Atari fuji with the scrolling rainbow effect. It uses multicolor players to get the rainbow, and uses Superchip RAM to scroll (or change) the colors. It's a 4K program, so I had to double-up the ROM image to 8K so the emulators can run it. The z26 emulator automatically detects the 8K+Superchip format, but you'll need to set the cart format to 8K+RAM for the Stella emulator (press Tab, change the properties, then use the backslash to reload the ROM). Also, it requires a modified score_graphics.asm file, with digit $A defined as a space (blank), so I could blank the first and last digits of the score. So if you want to compile the source, you'll need to use the 0.99c2 patch that I posted for the Superchip, as well as the modified score_graphics.asm file. I'm attaching a ZIP with my includes directory, but make sure you back up your original includes files, just in case.

 

MR

 

test_multicolor_player_2.bas

test_multicolor_player_2.bas.bin

includes.zip

Edited September 27, 2006 by SeaGtGruff

[Jess Ragan]

Pretty impressive! Did you do all that in Batari BASIC or is there some machine code in there as well?

 

JR

[SeaGtGruff]

Pretty impressive! Did you do all that in Batari BASIC or is there some machine code in there as well?

 

JR

Thank you! There's a tiny bit of in-line assembly code, but all it does is set the player color pointers to the Superchip RAM area where the color table is stored:

 

  asm
  LDA #<r000
  STA player0color
  STA player1color
  LDA #>r000
  STA player0color+1
  STA player1color+1
end

The rest is in batari BASIC, and is actually pretty simple, since all it needs to do (after setting up the player shapes, and the RAM color table) is to change the colors in the RAM color table. That's really the whole point of this little demo-- to show that the color tables for bB 0.99c's multi-colored players can be pointed to Superchip RAM, so that you can change the colors in the multi-color player by changing the RAM values, as opposed to defining a new color table in ROM. I'm not sure how useful that would be in a normal program, but it's handy for creating the scrolling rainbow effect without having to define 128 different color tables in ROM.

 

MR