island-story/src/main.s

INCLUDE "hardware.inc"
INCLUDE "util.inc"

SECTION "Header", ROM0[$100]

_entry:
    di
    jp start

rept $150 - _entry
    db 0
endr

SECTION "Frame", WRAM0

frame:: db

SECTION "VBlank", ROM0[$40]

handle_vblank:
    reti

SECTION "Code", ROM0

start:
    ld hl, rLCDC
    res 7, [hl]
    res 2, [hl]

    ld hl, rIE
    ld [hl], IEF_VBLANK

    call OAM_Init
    ; call Keys_Init
    ; call Player_Init

    ld hl, intro_Data
    call Map_Load

    ; set palette
    ld a, %11100100
    ld hl, rOBP0
    ld [hl], a
    ld hl, rBGP
    ld [hl], a

    ; enable lcd, sprites and interrupts
    ld hl, rLCDC
    set 7, [hl]
    set 1, [hl]
    ei

.loop:
    ld hl, frame
    inc [hl]

    call Keys_Update

    call scroll_update

    ; wait for vblank
    halt

    call Map_Update

    ; ~160 cycles
    ld a, HIGH(_OAM)
    call DMA_Start

    jp .loop

; TODO: Move into player movement routine
scroll_update:
; scroll map with arrow keys
    ld a, [keys]
    and PADF_UP
    jr z, .down

    ld d, 1
    call Map_ScrollUp
    ret

.down:
    ld a, [keys]
    and PADF_DOWN
    jr z, .right

    ld d, 1
    call Map_ScrollDown
    ret

.right:
    ld a, [keys]
    and PADF_RIGHT
    jr z, .left

    ld d, 1
    call Map_ScrollRight
    ret

.left:
    ld a, [keys]
    and PADF_LEFT
    ret z

    ld d, 1
    call Map_ScrollLeft