Space Invaders Arcade
I needed a break from other coding. Therefore, when @ZeroPage Homebrew announced that they would play INV+ (and show a demo named INV3), I remembered an old Space Invaders demo which I had done in 2001 and 2003. Using the RESP trick, I was able to display 11 invaders per row, like the arcade game.
So I went back to the demo and decided as an intermediate project I might make a nice little (4K) game out of it. Over the past days I have completed the overall display kernel. This gives
For those who are interested into details, I will try to explain the invader kernel code, which runs in Zeropage-RAM.
This is the code which is copied into RAM:
;---------------------------------------------------------------
KernelCode SUBROUTINE ; patched into
;---------------------------------------------------------------
.loop ; @61..71
PatchInv = . + 1
lda InvaderGfx-1,y ; 4
PatchHM = . + 1
sta HMOVE
