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; graphics routine
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SUB_GFX JSR GET_DRAW_INFO ; sets y = OAM offset
LDA $157C,x ; \ $02 = direction
STA $02 ; /
LDA $00 ; \ tile x position = sprite x location ($00)
STA $0300,y ; /
LDA $01 ; \ tile y position = sprite y location ($01)
STA $0301,y ; /
LDA $15F6,x ; tile properties xyppccct, format
PHX
LDX $02 ; \ if direction == 0...
BNE NO_FLIP ; |
ORA #$40 ; / ...flip tile
NO_FLIP ORA $64 ; add in tile priority of level
STA $0303,y ; store tile properties
LDA #$82 ; \ store tile
STA $0302,y ; /
PLX
INY ; \ increase index to sprite tile map ($300)...
INY ; | ...we wrote 1 16x16 tile...
INY ; | ...sprite OAM is 8x8...
INY ; / ...so increment 4 times
LDY #$02 ; \ 460 = 2 (all 16x16 tiles)
LDA #$00 ; | A = (number of tiles drawn - 1)
JSL $01B7B3 ; / don't draw if offscreen
RTS ; return