4cade/src/fx/fx.hgr.meet.in.the.middle.a
2020-03-17 15:30:20 -07:00

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;license:MIT
;(c) 2019 by 4am
;
!cpu 6502
!to "build/FX/MEETINTHEMIDDLE",plain
*=$6000
maskindex = $fc
row = $fd
col1 = $fe
col2 = $ff
!source "src/constants.a"
lda #0
sta col1
lda #39
sta col2
@colloop
lda #6
sta maskindex
jsr WaitForVBL
@maskloop
ldx maskindex
lda copymasks1,x
sta @copymask1
lda copymasks2,x
sta @copymask2
lda #23
sta row
@rowloop
lda row
asl
asl
asl
jsr HGRCalc
clc
ldx #8
@blockloop
ldy col1
lda ($26),y
eor ($3c),y
@copymask1=*+1
and #0 ; SMC
eor ($26),y
sta ($26),y
ldy col2
lda ($26),y
eor ($3c),y
@copymask2=*+1
and #0 ; SMC
eor ($26),y
sta ($26),y
lda $27
adc #4
sta $27
eor #$60
sta $3d
dex
bne @blockloop
dec row
bpl @rowloop
lda #1
jsr WaitForKeyWithTimeout
bmi @exit
dec maskindex
bpl @maskloop
inc col1
dec col2
lda col1
cmp #20
bne @colloop
@exit jmp UnwaitForVBL
copymasks1
!byte %11111111
!byte %10111111
!byte %10011111
!byte %10001111
!byte %10000111
!byte %10000011
!byte %10000001
copymasks2
!byte %11111111
!byte %11111110
!byte %11111100
!byte %11111000
!byte %11110000
!byte %11100000
!byte %11000000
!source "src/wait.a"
!source "src/fx/fx.hgr.common.a"