RegisterName.asm

; BANK $0C

; Displays the alphabet and allows entering text
; Used for savegame and character names
; Text is saved to the $580-... area
;
*=$871D
RegisterName:
; This draws the whole alphabet
  lda #$08  ; X
  sta $2A
  lda #$0C  ; Y
  sta $29
  lda #$14  ; Columns
  sta $2E
  lda #$06  ; Rows
  sta $2D
  lda #$03  ; Ptr 3: the input "keyboard"
  sta $30
  jsr DrawTextPreGame

; This draws 5 empty spaces just above it?
; Likely where the input text will be displayed after each character entry
  lda #$08
  sta $2A
  lda #$0A
  sta $29
  lda #$05
  sta $2E
  lda #$01
  sta $2D
  lda #$17  ; Ptr $17: five empty spaces
  sta $30
  jsr DrawTextPreGame

; X = Index of currently selected "key"
; Y = Used to index the area of RAM where we store the text
; A = Count of entered characters
; Could have saved 3 bytes and CPU cycles by doing LAX #$00 TAY instead
  ldx #$00
  ldy #$00
  lda #$00
  sta $17

_GetInput:
  jsr UpdateCursorTextInput
  jsr ControllerInput_Bank0C
  lda _ControllerStatus
  cmp #$01  ; D-pad Right
  bne $876A
  cpx #$27  ; END "Key" (can't move to the right of that)
  bne _CursorRight
  jmp _GetInput

_CursorRight:
  inx
  jmp _GetInput

  cmp #$02  ; D-pad Left
  bne _ButtonUp
  cpx #$00
  bne _CursorLeft
  jmp _GetInput

_CursorLeft:
  dex
  jmp _GetInput

_ButtonUp:
  cmp #$08  ; D-pad Up
  bne _ButtonDown
  lda KeyIndexTbl_Up,X
  tax
  jmp _GetInput

_ButtonDown:
  cmp #$04  ; D-pad Down
  bne _ButtonA
  lda KeyIndexTbl_Down,X
  tax
  jmp _GetInput

_ButtonA:
  cmp #$80  ; Button A
  beq $8796
  jmp _GetInput

  stx $19
  sty $18
  cpx #$26  ; Backspace "key"
  bcc _EnterCharacter
  beq _Backspace
  rts       ; Return if END was selected
            ; Note that there is no check for empty text here

; User chose to end text input
_Backspace:
  lda $17
  bne _DeleteLast
  jmp _GetInput ; Back to input polling if text length is zero

_DeleteLast:
  dec $17
  ldy $17
  lda #$FF
  sta $0580,Y
  dec $17
  jmp _DisplayEnteredText

; User pressed "A" on an input character
_EnterCharacter:
  lda $17
  cmp #$05  ; Maximum length
  bne _AddNew
  jmp _GetInput

_AddNew:
  lda AlphabetTileIdTbl,X
  ldy $17
  sta $0580,Y
  lda #$FF
  sta $0581,Y

_DisplayEnteredText:
  lda #$08
  sta $2A
  lda #$09
  sta $29
  lda #$0A
  sta $2E
  lda #$01
  sta $2D
  lda #$FF
  sta $30

; Save cursor position
  lda $19
  pha
  lda $18
  pha
  lda $17
  pha

  jsr DrawTextPreGame

; Restore cursor position
  pla
  sta $17
  pla
  sta $18
  tay
  pla
  sta $19
  tax
  inc $17
  jmp _GetInput

; Index of the next key in the text input panel when moving
; the cursor up
*=$8822
KeyIndexTbl_Down:
.byte $0A, $0B, $0C, $0D, $0E, $0F, $10, $11
.byte $12, $13, $14, $15, $16, $17, $18, $19
.byte $1A, $1B, $24, $25, $1C, $1D, $1E, $1F
.byte $20, $21, $22, $23, $26, $26, $26, $26
.byte $26, $26, $26, $26, $26, $26, $26, $27

; Index of the next key in the text input panel when moving
; the cursor down
*=$884A
KeyIndexTbl_Up:
.byte $00, $01, $02, $03, $04, $05, $06, $07
.byte $08, $09, $00, $01, $02, $03, $04, $05
.byte $06, $07, $08, $09, $0A, $0B, $0C, $0D
.byte $0E, $0F, $10, $11, $14, $15, $16, $17
.byte $18, $19, $1A, $1B, $12, $13, $22, $24

; Tile IDs for alphabet letters, used for text input
*=$87FC
AlphabetTileIdTbl:
.byte $8A, $8B, $8C, $8D, $8E, $8F, $90, $91
.byte $92, $93, $94, $95, $96, $97, $98, $99
.byte $9A, $9B, $9C, $9D, $9E, $9F, $A0, $A1
.byte $A2, $A3