;license:MIT
;(c) 2019 by 4am
;
!cpu 6502
!to "build/FX.INDEXED/SOFT.UD",plain
*=$6000

maskindex = $fc
row = $fd

         !source "src/fx/macros.a"
         !source "src/constants.a"

         lda   #$FA
         sta   row
@rowloop
         lda   #6
         sta   maskindex
         jsr   WaitForVBL
@maskloop
         lda   row
         bmi   @skiprow
         cmp   #24
         bcs   @skiprow
         asl
         asl
         asl
         jsr   HGRCalc

         lda   #<masks
         sta   @basemaskaddr
         lda   #>masks
         sta   @basemaskaddr+1
         lda   maskindex
         asl
         asl
         asl
         clc
         adc   @basemaskaddr
         sta   @basemaskaddr
         bcc   +
         inc   @basemaskaddr+1
+
         ldx   #7
         clc
@blockloop
@basemaskaddr=*+1
         lda   $FDFD,x               ; SMC
         sta   @copymask
         ldy   #39
@colloop
         lda   ($26),y
         eor   ($3c),y
@copymask=*+1
         and   #0                    ; SMC
         eor   ($26),y
         sta   ($26),y
         dey
         bpl   @colloop
         +HGR_INC_WITHIN_BLOCK
         dex
         bpl   @blockloop

@skiprow
         inc   row
         dec   maskindex
         bpl   @maskloop

         lda   #40
         jsr   WaitForKeyWithTimeout
         bmi   @exit

         dec   row
         dec   row
         dec   row
         dec   row
         dec   row
         dec   row
         lda   row
         bmi   @rowloop
         cmp   #24
         bcc   @rowloop

@exit    jmp   UnwaitForVBL

masks
         !byte %10000000
         !byte %10000000
         !byte %10000000
         !byte %10001000
         !byte %10001000
         !byte %10000000
         !byte %10000000
         !byte %10000000

         !byte %10000000
         !byte %10000000
         !byte %10010100
         !byte %10001000
         !byte %10001000
         !byte %10010100
         !byte %10000000
         !byte %10000000

         !byte %10000000
         !byte %10000000
         !byte %10011100
         !byte %10011100
         !byte %10011100
         !byte %10011100
         !byte %10000000
         !byte %10000000

         !byte %10000000
         !byte %10101010
         !byte %10011100
         !byte %10111110
         !byte %10011100
         !byte %10011100
         !byte %10101010
         !byte %10000000

         !byte %10000000
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10000000

         !byte %11010101
         !byte %10111110
         !byte %11111111
         !byte %10111110
         !byte %11111111
         !byte %10111110
         !byte %10111110
         !byte %11010101

         !byte %11111111
         !byte %11111111
         !byte %11111111
         !byte %11111111
         !byte %11111111
         !byte %11111111
         !byte %11111111
         !byte %11111111

         !source "src/wait.a"
         +HGR_CALC_ROUTINES