dcb "INIT" RTL dcb "MAIN" JSR Graphics ; I've added this label. We'll jump here to draw the graphics. RTL ; After drawing the graphics, end our code. ;=================================== ; GRAPHICS ROUTINE HERE ;=================================== Graphics: JSR GET_DRAW_INFO LDA $00 STA $0300,y LDA $01 STA $0301,y LDA #$E6 STA $0302,y LDA #%00000110 ORA $64 STA $0303,y INY INY INY INY LDY #$02 LDA #$00 JSL $01B7B3 RTS ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; GET_DRAW_INFO ; This is a helper for the graphics routine. It sets off screen flags, and sets up ; variables. It will return with the following: ; ; Y = index to sprite OAM ($300) ; $00 = sprite x position relative to screen boarder ; $01 = sprite y position relative to screen boarder ; ; It is adapted from the subroutine at $03B760 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; SPR_T1 dcb $0C,$1C SPR_T2 dcb $01,$02 GET_DRAW_INFO STZ $186C,x ; reset sprite offscreen flag, vertical STZ $15A0,x ; reset sprite offscreen flag, horizontal LDA $E4,x ; \ CMP $1A ; | set horizontal offscreen if necessary LDA $14E0,x ; | SBC $1B ; | BEQ ON_SCREEN_X ; | INC $15A0,x ; / ON_SCREEN_X LDA $14E0,x ; \ XBA ; | LDA $E4,x ; | REP #$20 ; | SEC ; | SBC $1A ; | mark sprite invalid if far enough off screen CLC ; | ADC.W #$0040 ; | CMP.W #$0180 ; | SEP #$20 ; | ROL A ; | AND #$01 ; | STA $15C4,x ; / BNE INVALID ; LDY #$00 ; \ set up loop: LDA $1662,x ; | AND #$20 ; | if not smushed (1662 & 0x20), go through loop twice BEQ ON_SCREEN_LOOP ; | else, go through loop once INY ; / ON_SCREEN_LOOP LDA $D8,x ; \ CLC ; | set vertical offscreen if necessary ADC SPR_T1,y ; | PHP ; | CMP $1C ; | (vert screen boundry) ROL $00 ; | PLP ; | LDA $14D4,x ; | ADC #$00 ; | LSR $00 ; | SBC $1D ; | BEQ ON_SCREEN_Y ; | LDA $186C,x ; | (vert offscreen) ORA SPR_T2,y ; | STA $186C,x ; | ON_SCREEN_Y DEY ; | BPL ON_SCREEN_LOOP ; / LDY $15EA,x ; get offset to sprite OAM LDA $E4,x ; \ SEC ; | SBC $1A ; | $00 = sprite x position relative to screen boarder STA $00 ; / LDA $D8,x ; \ SEC ; | SBC $1C ; | $01 = sprite y position relative to screen boarder STA $01 ; / RTS ; return INVALID PLA ; \ return from *main gfx routine* subroutine... PLA ; | ...(not just this subroutine) RTS ; /

PHX LDA $13 LSR ;\ LSR ; | Slowers the animation rate. LSR ;/ AND #$01 TAX LDA TILEMAP,x STA $0302,y PLX

dcb "INIT" RTL dcb "MAIN" PHB ;\ PHK ; | Change the data bank to the one our code is running from. PLB ; | This is a good practice. JSR SpriteCode ; | Jump to the sprite's function. PLB ; | Restore old data bank. RTL ;/ And return. ;=================================== ;Sprite Function ;=================================== RETURN: RTS SpriteCode: JSR Graphics LDA $14C8,x CMP #$08 BNE RETURN LDA $9D BNE RETURN JSR SUB_OFF_SCREEN_X0 ;=================================== ;Graphics Code ;=================================== TILEMAP: dcb $CA,$CC Graphics: JSR GET_DRAW_INFO ; Before actually coding the graphics, we need a routine that will get the current sprite's value ; into the OAM. ; The OAM being a place where the tile data for the current sprite will be stored. LDA $00 ;\ STA $0300,y ;/ Draw the X position of the sprite LDA $01 ;\ STA $0301,y ;/ Draw the Y position of the sprite ;Those 2 above are always needed to figure out the X/Y position of the sprite PHX LDA $13 LSR ;\ LSR ; | Slowers the animation rate. LSR ;/ AND #$01 TAX LDA TILEMAP,x STA $0302,y PLX LDA #$07 ORA $64 STA $0303,y ; Write the YXPPCCCT property byte of the sprite ; See this part of the tutorial again for more info INY ;\ INY ; | The OAM is 8x8, but our sprite is 16x16 .. INY ; | So increment it 4 times. INY ;/ LDY #$02 ; Y ends with the tile size .. 02 means it's 16x16 LDA #$00 ; A -> number of tiles drawn - 1. ; I drew only 1 tile so I put in 1-1 = 00. JSL $01B7B3 ; Call the routine that draws the sprite. RTS ; Never forget this!

SpriteCode: JSR Graphics LDA $14C8,x CMP #$08 BNE RETURN LDA $9D BNE RETURN JSR SUB_OFF_SCREEN_X0