4sports/src/fx/fx.hgr.soft.diagonal.a

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

y = $fc
row = $fd
col = $fe
counter = $ff

hgrlo    =     $0200                 ; [$C0 bytes]
hgr1hi   =     $0300                 ; [$C0 bytes]

         !source "src/fx/macros.a"

!macro RESET_HGR_CALC_BY_7 {
         lda   $27
         sec
         sbc   #$1c
         sta   $27
         eor   #$60
         sta   $3d
}

         +BUILD_HGR_LOOKUP_TABLES hgrlo, hgr1hi

         lda   #(40+24+7-1) ; columns + rows + blocks per row - 1
         sta   counter

         lda   #39
         sta   col
ColLoop
         lda   #23
         sta   row
         ldy   col
         sty   y
RowLoop
         ; [speedopt] calculate HGR base addresses once per row
         lda   row
         asl
         asl
         asl
         tax
         lda   hgrlo, x
         sta   $26
         sta   $3c
         lda   hgr1hi, x
         sta   $27
         eor   #$60
         sta   $3d

         ldy   y
         +IS_Y_OFFSCREEN
         +LBCS @block2

         ; [speedopt] HGRBlockCopyWithMask but hardcoded for this block's masks
         ldx   #7
         clc
!for i, 0, 7 {
         +COPY_BIT $3c, $26, copymasks1
!if i < 7 {
         dex
         +HGR_INC_WITHIN_BLOCK
}
}
         ; [speedopt] reset HGR base addresses instead of recalculating them from scratch
         +RESET_HGR_CALC_BY_7
@block2
         iny
         +IS_Y_OFFSCREEN
         +LBCS @block3

         ldx   #7
         clc
!for i, 0, 7 {
         +COPY_BIT $3c, $26, copymasks2
!if i < 7 {
         dex
         +HGR_INC_WITHIN_BLOCK
}
}
         +RESET_HGR_CALC_BY_7
@block3
         iny
         +IS_Y_OFFSCREEN
         +LBCS @block4

         ldx   #7
         clc
!for i, 0, 7 {
         +COPY_BIT $3c, $26, copymasks3
!if i < 7 {
         dex
         +HGR_INC_WITHIN_BLOCK
}
}
         +RESET_HGR_CALC_BY_7
@block4
         iny
         +IS_Y_OFFSCREEN
         +LBCS @block5

         ldx   #7
         clc
!for i, 0, 7 {
         +COPY_BIT $3c, $26, copymasks4
!if i < 7 {
         dex
         +HGR_INC_WITHIN_BLOCK
}
}
         +RESET_HGR_CALC_BY_7
@block5
         iny
         +IS_Y_OFFSCREEN
         +LBCS @block6

         ldx   #7
         clc
!for i, 0, 7 {
         +COPY_BIT $3c, $26, copymasks5
!if i < 7 {
         dex
         +HGR_INC_WITHIN_BLOCK
}
}
         +RESET_HGR_CALC_BY_7
@block6
         iny
         +IS_Y_OFFSCREEN
         +LBCS @block7

         ldx   #7
         clc
!for i, 0, 7 {
         +COPY_BIT $3c, $26, copymasks6
!if i < 7 {
         dex
         +HGR_INC_WITHIN_BLOCK
}
}
         +RESET_HGR_CALC_BY_7
@block7
         iny
         +IS_Y_OFFSCREEN
         +LBCS @nextrow

         ; [speedopt] HGRBlockCopy but inlined
         clc
!for i, 0, 7 {
         lda   ($3c),y
         sta   ($26),y
!if i < 7 {
         +HGR_INC_WITHIN_BLOCK
}
}
         ; don't need RESET_HGR_CALC_BY_7 here because we're done with this row
@nextrow
         ldy   y
         iny
         sty   y
         dec   row
         +LBPL RowLoop
         lda   $c000
         bmi   @exit
         dec   col
         dec   counter
         +LBNE ColLoop
@exit    rts

copymasks1
         !byte %10000000
         !byte %10000000
         !byte %10000000
         !byte %10001000
         !byte %10001000
         !byte %10000000
         !byte %10000000
         !byte %10000000
copymasks2
         !byte %10000000
         !byte %10000000
         !byte %10010100
         !byte %10001000
         !byte %10001000
         !byte %10010100
         !byte %10000000
         !byte %10000000
copymasks3
         !byte %10000000
         !byte %10000000
         !byte %10011100
         !byte %10011100
         !byte %10011100
         !byte %10011100
         !byte %10000000
         !byte %10000000
copymasks4
         !byte %10000000
         !byte %10101010
         !byte %10011100
         !byte %10111110
         !byte %10011100
         !byte %10011100
         !byte %10101010
         !byte %10000000
copymasks5
         !byte %10000000
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10111110
         !byte %10000000
copymasks6
         !byte %11010101
         !byte %10111110
         !byte %11111111
         !byte %10111110
         !byte %11111111
         !byte %10111110
         !byte %10111110
         !byte %11010101