Files
alttpr-baserom/graphicsoverride.asm
2018-01-03 23:33:45 -05:00

62 lines
1.3 KiB
NASM

macro OverwriteVramTile(firstTileIndex, count)
LDA.w #<firstTileIndex>+512*8*8*4/16
LDX.b #<count>
JSR UploadTileToVram
endmacro
GraphicsOverrideHook:
JSL .resumeOriginalCode
LDA $0A ; Floor tileset loaded
CMP #$0A ; Floor tileset index used by Ice and Mire
BEQ .loadedIceOrMireFloor
RTL
.loadedIceOrMireFloor
LDA $040C ; Load dungeon number
CMP #$12 ; Ice Palace
BEQ .isInIcePalace
RTL
.isInIcePalace
; We've just loading the floor tiles in Ice Palace.
; Replace the bridge tiles with the bombos medallion
LDA.b #IcePalaceMedallionGfx>>16
STA $02
REP #$20
LDA.w #IcePalaceMedallionGfx
STA $00
%OverwriteVramTile($CA, 2)
%OverwriteVramTile($DA, 2)
SEP #$20
RTL
.resumeOriginalCode
; Overwritten instructions:
PHB
LDA.b #$00
PHA
PLB
LDA.b #$80
JML GraphicsOverrideResume
; A = VRAM word address to upload to (Actual VRAM address / 2)
; X = Tiles to upload
; $00-$02 = Pointer to graphics data
UploadTileToVram:
; TODO: This should probably be optimized with a DMA
STA $2116
TXA : ASL #4 : TAX ; X = Amount of words to upload (Tiles to upload * 16)
- LDA [$00]
STA $2118
INC $00
INC $00
DEX
BNE -
RTS
IcePalaceMedallionGfx:
incbin ice_bombos_floor.bin