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https://gitlab.com/xCrystal/pokecrystal-board.git
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86 lines
2.0 KiB
NASM
86 lines
2.0 KiB
NASM
CheckForHiddenItems: ; b8172
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; Checks to see if there are hidden items on the screen that have not yet been found. If it finds one, returns carry.
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call GetMapScriptHeaderBank
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ld [Buffer1], a
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; Get the coordinate of the bottom right corner of the screen, and load it in Buffer3/Buffer4.
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ld a, [XCoord]
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add SCREEN_WIDTH / 4
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ld [Buffer4], a
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ld a, [YCoord]
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add SCREEN_HEIGHT / 4
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ld [Buffer3], a
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; Get the pointer for the first BG event header in the map...
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ld hl, wCurrMapBGEventHeaderPointer
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ld a, [hli]
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ld h, [hl]
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ld l, a
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; ... before even checking to see if there are any BG events on this map.
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ld a, [wCurrMapBGEventCount]
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and a
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jr z, .nobgeventitems
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; For i = 1:wCurrMapBGEventCount...
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.loop
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; Store the counter in Buffer2, and store the BG event header pointer in the stack.
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ld [Buffer2], a
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push hl
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; Get the Y coordinate of the BG event.
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call .GetFarByte
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ld e, a
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; Is the Y coordinate of the BG event on the screen? If not, go to the next BG event.
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ld a, [Buffer3]
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sub e
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jr c, .next
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cp SCREEN_HEIGHT / 2
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jr nc, .next
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; Is the X coordinate of the BG event on the screen? If not, go to the next BG event.
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call .GetFarByte
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ld d, a
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ld a, [Buffer4]
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sub d
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jr c, .next
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cp SCREEN_WIDTH / 2
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jr nc, .next
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; Is this BG event a hidden item? If not, go to the next BG event.
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call .GetFarByte
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cp BGEVENT_ITEM
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jr nz, .next
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; Has this item already been found? If not, set off the Itemfinder.
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ld a, [Buffer1]
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call GetFarHalfword
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ld a, [Buffer1]
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call GetFarHalfword
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ld d, h
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ld e, l
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ld b, CHECK_FLAG
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call EventFlagAction
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ld a, c
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and a
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jr z, .itemnearby
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.next
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; Restore the BG event header pointer and increment it by the length of a BG event header.
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pop hl
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ld bc, 5
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add hl, bc
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; Restore the BG event counter and decrement it. If it hits zero, there are no hidden items in range.
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ld a, [Buffer2]
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dec a
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jr nz, .loop
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.nobgeventitems
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xor a
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ret
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.itemnearby
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pop hl
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scf
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ret
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; b81e2
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.GetFarByte: ; b81e2
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ld a, [Buffer1]
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call GetFarByte
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inc hl
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ret
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; b81ea
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