ref: 711e2d6143d59093a763f9bbd4a527f349fdeff8
dir: /engine/events/checkforhiddenitems.asm/
CheckForHiddenItems: ; b8172 ; Checks to see if there are hidden items on the screen that have not yet been found. If it finds one, returns carry. call GetMapScriptsBank ld [wBuffer1], a ; Get the coordinate of the bottom right corner of the screen, and load it in wBuffer3/wBuffer4. ld a, [wXCoord] add SCREEN_WIDTH / 4 ld [wBuffer4], a ld a, [wYCoord] add SCREEN_HEIGHT / 4 ld [wBuffer3], a ; Get the pointer for the first bg_event in the map... ld hl, wCurrMapBGEventsPointer ld a, [hli] ld h, [hl] ld l, a ; ... before even checking to see if there are any BG events on this map. ld a, [wCurrMapBGEventCount] and a jr z, .nobgeventitems ; For i = 1:wCurrMapBGEventCount... .loop ; Store the counter in wBuffer2, and store the bg_event pointer in the stack. ld [wBuffer2], a push hl ; Get the Y coordinate of the BG event. call .GetFarByte ld e, a ; Is the Y coordinate of the BG event on the screen? If not, go to the next BG event. ld a, [wBuffer3] sub e jr c, .next cp SCREEN_HEIGHT / 2 jr nc, .next ; Is the X coordinate of the BG event on the screen? If not, go to the next BG event. call .GetFarByte ld d, a ld a, [wBuffer4] sub d jr c, .next cp SCREEN_WIDTH / 2 jr nc, .next ; Is this BG event a hidden item? If not, go to the next BG event. call .GetFarByte cp BGEVENT_ITEM jr nz, .next ; Has this item already been found? If not, set off the Itemfinder. ld a, [wBuffer1] call GetFarHalfword ld a, [wBuffer1] call GetFarHalfword ld d, h ld e, l ld b, CHECK_FLAG call EventFlagAction ld a, c and a jr z, .itemnearby .next ; Restore the bg_event pointer and increment it by the length of a bg_event. pop hl ld bc, 5 add hl, bc ; Restore the BG event counter and decrement it. If it hits zero, there are no hidden items in range. ld a, [wBuffer2] dec a jr nz, .loop .nobgeventitems xor a ret .itemnearby pop hl scf ret ; b81e2 .GetFarByte: ; b81e2 ld a, [wBuffer1] call GetFarByte inc hl ret ; b81ea