DEF vFrameCount1 EQU VARIABLES_START
DEF vFrameCount2 equ vFrameCount1+1
DEF vFrameCount3 EQU vFrameCount2+1
PRINTLN "vframecount is ", vFrameCount1
DEF vTime EQU vFrameCount3+1 ; 16bit


ShuffleDeckSetup:
; Turn the LCD off
  ld hl, rLCDC
  bit 7, [hl]
  jp z, CardReadSetup_ScreenOff
ShuffleDeckSetup_BusyWait:
  ld a, [rLY]
  cp a, 143
  jp c, CardReadSetup_BusyWait
  ld [hl], 0

ShuffleDeckSetup_ScreenOff:
  ld a, 0 
  ldh [rLCDC], a
  
  ld hl, CardBackSprites ; source
  ld de, $8000; destination of copy
  ld bc, CardBackSpritesEnd - CardBackSprites ; length to copy
  call CopyRangeUnsafe
  
  ; set LCD and display registers
  ld a, %11100100
  ld [rBGP], a
  ld [rOBP0], a

  ld a, LCDCF_BLK01 | LCDCF_ON | LCDCF_BGON | LCDCF_OBJON | LCDCF_OBJ16
  ldh [rLCDC], a

  ld a, 0 
  ldh [vFrameCount1], a ; first starts at 0
  ldh [vTime], a 
  ldh [vTime+1], a 
  
  ; second starts at 1/3 length which is approximately L/2 - L/4 - L/8 + L/16 ?
  ld hl, Coords
  ld a, [hl]
  ld b, a 
  srl b 
  sub a, b ; L - L/2
  srl b
  sub a, b ; L - L/2 - L/4
  srl b
  add a, b ; L - L/2 - L/4 + L/8
  srl b
  sub a, b ; L - L/2 - L/4 + L/8 - L/16
  srl b
  add a, b ; L - L/2 - L/4 + L/8 - L/16 + L/32
  srl b
  sub a, b ; L - L/2 - L/4 + L/8 - L/16 + L/32 - L/64
  srl b
  add a, b ; L - L/2 - L/4 + L/8 - L/16 + L/32 - L/64 + L/128
  ; that should be approx 1/3 of L !
  ldh [vFrameCount2], a 
  
  ; third starts at 2/3 length which is approximately L/2 - L/4 + L/8 - L/16 ?
  ld hl, Coords
  ld a, [hl]
  ld b, a 
  srl b 
  sub a, b ; L - L/2
  srl b
  add a, b ; L - L/2 + L/4
  srl b
  sub a, b ; L - L/2 + L/4 - L/8
  srl b
  add a, b ; L - L/2 + L/4 - L/8 + L/16
  srl b
  sub a, b ; L - L/2 + L/4 - L/8 + L/16 - L/32
  srl b
  add a, b ; L - L/2 + L/4 - L/8 + L/16 - L/32 + L/64
  srl b
  sub a, b ; L - L/2 + L/4 - L/8 + L/16 - L/32 + L/64 - L/128
  ; that should be just about 2/3 of L !
  ldh [vFrameCount3], a 
  

  ; load graphics into vram for deck face
  ; set up variables: LFSR stuff
  ret ; return from cardreadsetup

ShuffleDeckUpdate:
  ; if pressing a key and unblocked:
  ; signal an animation to start
  ; turn on block
  ; if in animation state:
  ; increment timer
  ; if timer is max, turn off animation state and unblock?
  
  ld hl, vTime
  ldh a, [rDELTAT]
  ld b, a 
  ldh a, [vTime]
  add a, b
  ldh [vTime], a 
  ldh a, [vTime+1]
  adc a, 0 
  ldh [vTime+1], a ; increment time. when the 16bit time register is greater 
  ; than 4096 ($10_00) then one second has passed. so that's satisfied when
  ; vTime+1 is equal to or greater than $10
  
  cp a, $01
  jp c, ShuffleDeckUpdate_Done ; if the timer is less than $1000, skip to end
  
  ;otherwise reset the timer
  ld a, 0 
  ldh [vTime], a 
  ldh [vTime+1], a 
  
  
  ld hl, Coords
  
  ; and advance the frame counts
  ldh a, [vFrameCount1]
  inc a
  call ArrayClampLooping
  ldh [vFrameCount1], a 
  
  ldh a, [vFrameCount2]
  inc a
  call ArrayClampLooping
  ldh [vFrameCount2], a 
  
  ldh a, [vFrameCount3]
  inc a
  call ArrayClampLooping
  ldh [vFrameCount3], a 
  
ShuffleDeckUpdate_Done:
  ret

ShuffleDeckDraw:
  ld hl, Coords
  inc hl
  ld b, 0 
  ld a, [vFrameCount1]
  ld c, a 
  add hl, bc
  add hl, bc
  add hl, bc
  ld a, [hl+] 
  ld b, a ; y coordinate
  ld a, [hl+]
  ld c, a ; x coordinate
  ld a, [hl+]
  ld e, a ; spread value
  ld hl, $fe00
  call DrawWholeCard
  
  ld hl, Coords
  inc hl
  ld b, 0 
  ld a, [vFrameCount2]
  ld c, a 
  add hl, bc
  add hl, bc
  add hl, bc
  ld a, [hl+] 
  ld b, a ; y coordinate
  ld a, [hl+]
  ld c, a ; x coordinate
  ld a, [hl+]
  ld e, a ; spread value
  ld hl, $fe00 + 3*4
  call DrawWholeCard
  
  ld hl, Coords
  inc hl
  ld b, 0 
  ld a, [vFrameCount3]
  ld c, a 
  add hl, bc
  add hl, bc
  add hl, bc
  ld a, [hl+] 
  ld b, a ; y coordinate
  ld a, [hl+]
  ld c, a ; x coordinate
  ld a, [hl+]
  ld e, a ; spread value
  ld hl, $fe00 + 6*4
  call DrawWholeCard
  
  
  ret
  
ShuffleDeckTeardown:
  ret

DrawWholeCard: ; hl memory location, b y, c x, e step
  jp Draw3x3Card
Draw2x2Card:
; hl memory location, b y coord, c x coord, e step
  ; top-left
  ld d, $02
  call DrawTile
  
  ld a, c 
  add a, e ; addd stride to x
  ld c, a
  ld a, e
  cp a, 5
  ld d, $04
  call DrawTile

  ld d, $06
  ld a, c 
  add a, e ; add stride to x
  ;sub a, 8
  ld c, a
  call DrawTile
  
  push bc
  ld b, 0
  ld c, 6*4
  add hl, bc ; advance by 6 oam slots?
  pop bc
  
  ld d, $08
  ld a, b
  add a, 8
  add a, 8
  ld b, a ; add 16 to y coord
  ld a, c 
  sub a, e 
  sub a, e
  ld c, a ; subtract stridex2 from x
  call DrawTile
  
  
  ld d, $0a
  ld a, c 
  add a, e
  ld c, a
  call DrawTile
  
  ld d, $0c
  ld a, c 
  add a, e
  ld c, a
  call DrawTile
  
  push bc
  ld b, 0
  ld c, 6*4
  add hl, bc ; advance by 6 oam slots so the other two cards have room
  pop bc
  
  ld d, $0e
  ld a, b
  sub a, 8
  sub a, 8
  add a, e
  add a, e
  add a, e
  add a, e
  ld b, a ; add stridex2 to y coord
  ld a, c 
  sub a, e 
  sub a, e
  ld c, a ; subtract stridex2 from x
  call DrawTile
  
  ld d, $10
  ld a, c 
  add a, e
  ld c, a
  call DrawTile
  
  ld d, $12
  ld a, c 
  add a, e
  ld c, a
  call DrawTile
  ret

Draw3x3Card:
; hl memory location, b y coord, c x coord, e step
  ; top-left
  ld d, $02
  call DrawTile
  
  ld a, c 
  add a, e ; addd stride to x
  ld c, a
  ld a, e
  cp a, 5
  ld d, $04
  call DrawTile

  ld d, $06
  ld a, c 
  add a, e ; add stride to x
  ;sub a, 8
  ld c, a
  call DrawTile
  
  push bc
  ld b, 0
  ld c, 6*4
  add hl, bc ; advance by 6 oam slots?
  pop bc
  
  ld d, $08
  ld a, b
  add a, 8
  add a, 8
  ld b, a ; add 16 to y coord
  ld a, c 
  sub a, e 
  sub a, e
  ld c, a ; subtract stridex2 from x
  call DrawTile
  
  
  ld d, $0a
  ld a, c 
  add a, e
  ld c, a
  call DrawTile
  
  ld d, $0c
  ld a, c 
  add a, e
  ld c, a
  call DrawTile
  
  push bc
  ld b, 0
  ld c, 6*4
  add hl, bc ; advance by 6 oam slots so the other two cards have room
  pop bc
  
  ld d, $0e
  ld a, b
  sub a, 8
  sub a, 8
  add a, e
  add a, e
  add a, e
  add a, e
  ld b, a ; add stridex2 to y coord
  ld a, c 
  sub a, e 
  sub a, e
  ld c, a ; subtract stridex2 from x
  call DrawTile
  
  ld d, $10
  ld a, c 
  add a, e
  ld c, a
  call DrawTile
  
  ld d, $12
  ld a, c 
  add a, e
  ld c, a
  call DrawTile
  ret
  
DrawTile: ; b: y. a: x. d: sprite. hl: location of sprite in OAM
  ld a, b
  ld [hl+], a ; y byte
  
  ld a, c 
  ld [hl+], a ; x byte
  
  ld a, d
  ld [hl+], a ; tile index
  ld a, $00 
  ld [hl+], a ; attributes
  ret 
Coords: ; y, x, spread
db 160, $1f, $13, $6, $1f, $13, $6, $1f, $13, $6, $1f, $13, $6, $1f, $13, $6, 
db $1e, $14, $6, $1e, $14, $6, $1e, $14, $7, $1e, $15, $7, $1e, $16, $7, $1e, $16, 
db $7, $1e, $17, $7, $1e, $18, $7, $1e, $19, $7, $1d, $1a, $7, $1d, $1b, $7, $1d, $1d, 
db $7, $1d, $1e, $7, $1d, $1f, $7, $1d, $21, $7, $1d, $22, $7, $1d, $24, $7, $1d, $26, 
db $8, $1d, $27, $8, $1d, $29, $8, $1d, $2b, $8, $1c, $2d, $8, $1c, $2f, $8, $1c, $31, 
db $8, $1c, $33, $8, $1c, $35, $8, $1c, $37, $8, $1c, $3a, $8, $1c, $3c, $8, $1c, $3e, 
db $8, $1c, $40, $8, $1c, $43, $8, $1c, $45, $8, $1c, $47, $8, $1c, $4a, $8, $1c, $4c, 
db $8, $1c, $4e, $8, $1c, $51, $8, $1c, $53, $8, $1c, $55, $8, $1c, $58, $8, $1c, $5a, 
db $8, $1c, $5c, $8, $1c, $5f, $8, $1c, $61, $8, $1c, $63, $8, $1c, $65, $8, $1c, $68, 
db $8, $1c, $6a, $8, $1c, $6c, $8, $1d, $6e, $8, $1d, $70, $8, $1d, $72, $8, $1d, $74, 
db $8, $1d, $76, $7, $1d, $77, $7, $1d, $79, $7, $1d, $7b, $7, $1d, $7c, $7, $1d, $7e, 
db $7, $1d, $7f, $7, $1d, $81, $7, $1e, $82, $7, $1e, $83, $7, $1e, $84, $7, $1e, $85, 
db $7, $1e, $86, $7, $1e, $87, $7, $1e, $88, $7, $1e, $89, $6, $1e, $89, $6, $1f, $8a, 
db $6, $1f, $8a, $6, $1f, $8b, $6, $1f, $8b, $6, $1f, $8b, $6, $1f, $8b, $6, $1f, $8b, 
db $6, $1f, $8b, $6, $1f, $8b, $6, $20, $8a, $6, $20, $8a, $6, $20, $8a, $5, $20, $89, 
db $5, $20, $88, $5, $20, $88, $5, $20, $87, $5, $20, $86, $5, $20, $85, $5, $21, $84, 
db $5, $21, $83, $5, $21, $81, $5, $21, $80, $5, $21, $7f, $5, $21, $7d, $5, $21, $7c, 
db $5, $21, $7a, $5, $21, $78, $4, $21, $77, $4, $21, $75, $4, $21, $73, $4, $22, $71, 
db $4, $22, $6f, $4, $22, $6d, $4, $22, $6b, $4, $22, $69, $4, $22, $67, $4, $22, $64, 
db $4, $22, $62, $4, $22, $60, $4, $22, $5e, $4, $22, $5b, $4, $22, $59, $4, $22, $57, 
db $4, $22, $54, $4, $22, $52, $4, $22, $50, $4, $22, $4d, $4, $22, $4b, $4, $22, $49, 
db $4, $22, $46, $4, $22, $44, $4, $22, $42, $4, $22, $3f, $4, $22, $3d, $4, $22, $3b, 
db $4, $22, $39, $4, $22, $36, $4, $22, $34, $4, $22, $32, $4, $21, $30, $4, $21, $2e, 
db $4, $21, $2c, $4, $21, $2a, $4, $21, $28, $5, $21, $27, $5, $21, $25, $5, $21, $23, 
db $5, $21, $22, $5, $21, $20, $5, $21, $1f, $5, $21, $1d, $5, $20, $1c, $5, $20, $1b, 
db $5, $20, $1a, $5, $20, $19, $5, $20, $18, $5, $20, $17, $5, $20, $16, $5, $20, $15, 
db $6, $20, $15, $6, $1f, $14, $6, $1f, $14, $6, $1f, $13, $6, $1f, $13, $6


CardBackSprites:
  db $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
  db $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00

	db $00,$ff,$7f,$ff,$7f,$ff,$60,$ff,$6f,$ff,$6d,$fa,$6a,$fd,$6d,$fa
	db $6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa
	
	db $00,$ff,$ff,$ff,$ff,$ff,$00,$ff,$ff,$ff,$55,$aa,$aa,$55,$55,$aa
	db $aa,$55,$55,$aa,$aa,$55,$55,$aa,$aa,$55,$55,$aa,$aa,$55,$55,$aa
	
	db $00,$ff,$fe,$ff,$fe,$ff,$06,$ff,$f6,$ff,$56,$bf,$b6,$5f,$56,$bf
	db $b6,$5f,$56,$bf,$b6,$5f,$56,$bf,$b6,$5f,$56,$bf,$b6,$5f,$56,$bf
  
  db $6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa
  db $6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa
  
  db $aa,$55,$55,$aa,$aa,$55,$55,$aa,$aa,$55,$55,$aa,$aa,$55,$55,$aa
	db $aa,$55,$55,$aa,$aa,$55,$55,$aa,$aa,$55,$55,$aa,$aa,$55,$55,$aa
	
	db $b6,$5f,$56,$bf,$b6,$5f,$56,$bf,$b6,$5f,$56,$bf,$b6,$5f,$56,$bf
	db $b6,$5f,$56,$bf,$b6,$5f,$56,$bf,$b6,$5f,$56,$bf,$b6,$5f,$56,$bf

  db $6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa,$6a,$fd,$6d,$fa
	db $6a,$fd,$6d,$fa,$6a,$fd,$6f,$ff,$60,$ff,$7f,$ff,$7f,$ff,$00,$ff

  db $aa,$55,$55,$aa,$aa,$55,$55,$aa,$aa,$55,$55,$aa,$aa,$55,$55,$aa
  db $aa,$55,$55,$aa,$aa,$55,$ff,$ff,$00,$ff,$ff,$ff,$ff,$ff,$00,$ff

  db $b6,$5f,$56,$bf,$b6,$5f,$56,$bf,$b6,$5f,$56,$bf,$b6,$5f,$56,$bf
  db $b6,$5f,$56,$bf,$b6,$5f,$f6,$ff,$06,$ff,$fe,$ff,$fe,$ff,$00,$ff

CardBackSpritesEnd: