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Milestone 3 - the _MAIN_*Mario* code works better than it did now, but it still freaks out and cascades the tiles across the screen if I put it into the main loop.

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Andrew Kesterson
2012-11-03 12:46:27 -04:00
parent d733418509
commit 9b89a6788e
1 changed files with 27 additions and 24 deletions
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51
nesgame.S
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@@ -30,6 +30,7 @@ START:
TXS ;; Move the contents of X to the stack pointer TXS ;; Move the contents of X to the stack pointer
INX ;; increment X by 1, which causes overflow, so INX ;; increment X by 1, which causes overflow, so
;; now X is 0 ;; now X is 0
STX $2000 ;; set PPU flag to disable NMI (0x2000 = 0) STX $2000 ;; set PPU flag to disable NMI (0x2000 = 0)
STX $2001 ;; set PPU flag to disable rendering (0x2001 = 0) STX $2001 ;; set PPU flag to disable rendering (0x2001 = 0)
STX $4010 ;; disable APU IRQs, no audio STX $4010 ;; disable APU IRQs, no audio
@@ -61,7 +62,7 @@ _START_clearmem:
;; (0200-07FF) ;; (0200-07FF)
LDA #$FE ;; These two are clearing all of the sprite LDA #$FE ;; These two are clearing all of the sprite
STA sprStartClearing, x ;; OAM; previous tutorial had this at 0300, STA $0200, x ;; OAM; previous tutorial had this at 0300,
;; which may have been wrong. We don't HAVE ;; which may have been wrong. We don't HAVE
;; to reserve this range for OAM; we could ;; to reserve this range for OAM; we could
;; just manually poke bits into the PPU, but ;; just manually poke bits into the PPU, but
@@ -164,12 +165,18 @@ _MAIN_LoadPaletteLoop:
LDA #%00010000 ;; turn on sprites, no more background color LDA #%00010000 ;; turn on sprites, no more background color
STA $2001 ;; Write to PPU Control Register 2 STA $2001 ;; Write to PPU Control Register 2
_MAIN_loop: LDX #$0
_MAIN_CopyMarioToOAM:
LDA sprMario, x
STA $0200, x
INX
CPX #$20
BNE _MAIN_CopyMarioToOAM
LDX #$0 LDX #$0
_MAIN_MoveMarioToPlayer_x: _MAIN_MoveMarioToPlayer_x:
LDA playerx LDA playerx
ADC sprMario_x, x ADC $0203, x
STA sprMario_x, x STA $0203, x
INX INX
INX INX
INX INX
@@ -179,14 +186,15 @@ _MAIN_MoveMarioToPlayer_x:
LDX #$0 LDX #$0
_MAIN_MoveMarioToPlayer_y: _MAIN_MoveMarioToPlayer_y:
LDA playery LDA playery
ADC sprMario, x ADC $0200, x
STA sprMario, x STA $0200, x
INX INX
INX INX
INX INX
INX INX
CPX #$20 CPX #$20
BNE _MAIN_MoveMarioToPlayer_y BNE _MAIN_MoveMarioToPlayer_y
_MAIN_loop:
JMP _MAIN_loop ;; Loop forever JMP _MAIN_loop ;; Loop forever
NMI: NMI:
@@ -195,7 +203,7 @@ NMI:
;; to pull OAM from $0200, and do a DMA transfer. ;; to pull OAM from $0200, and do a DMA transfer.
LDA #$00 LDA #$00
STA $2003 STA $2003
LDA #$FF LDA #$02
STA $4014 ; 4014 is the OAM_DMA operation, which will STA $4014 ; 4014 is the OAM_DMA operation, which will
; do a DMA from the (LDA|$2003) address, ; do a DMA from the (LDA|$2003) address,
; for FF bytes (in our case $0200-$02FF), ; for FF bytes (in our case $0200-$02FF),
@@ -210,17 +218,15 @@ NMI:
;; between them. ;; between them.
;; .. How to know when we have written enough ;; .. How to know when we have written enough
;; code? .. ;; code? ..
palette: palette:
.db $0F,$31,$32,$33,$0F,$35,$36,$37,$0F,$39,$3A,$3B,$0F,$3D,$3E,$0F .db $0F,$31,$32,$33,$0F,$35,$36,$37,$0F,$39,$3A,$3B,$0F,$3D,$3E,$0F
.db $0F,$1C,$15,$14,$0F,$02,$38,$3C,$0F,$1C,$15,$14,$0F,$02,$38,$3C .db $0F,$1C,$15,$14,$0F,$02,$38,$3C,$0F,$1C,$15,$14,$0F,$02,$38,$3C
playerx: playerx:
.db $01 .db $08
playery: playery:
.db $01 .db $08
playerSprIndex: curSprIndex:
.db $00 .db $00
;; I put the OAM copy here instead of $0200 because I want to ;; I put the OAM copy here instead of $0200 because I want to
;; allow me to initialize some basic sprite organizations (such as ;; allow me to initialize some basic sprite organizations (such as
;; mario standing) without having to do a bunch of pokes into my ;; mario standing) without having to do a bunch of pokes into my
@@ -228,21 +234,18 @@ playerSprIndex:
;; the X and Y position. But I couldn't get the NMI copying to work ;; the X and Y position. But I couldn't get the NMI copying to work
;; correctly when trying to set a bank to .org at $0200; I'm probably ;; correctly when trying to set a bank to .org at $0200; I'm probably
;; just doing it wrong, but for now this works. ;; just doing it wrong, but for now this works.
.org $FF00
sprMario: sprMario:
;; each 4-byte pair goes directly into the OAM ;; each 4-byte pair goes directly into the OAM
.db $10,$00,$00 ; mario top left Y,tile,attrs .db $00,$00,$00 ; mario top left Y,tile,attrs
sprMario_x: sprMario_x:
.db $10 ; mario top left X .db $00 ; mario top left X
.db $10,$01,$00,$18 ; mario top right .db $00,$01,$00,$08 ; mario top right
.db $18,$02,$00,$10 ; mario middle left .db $08,$02,$00,$00 ; mario middle left
.db $18,$03,$00,$18 ; mario middle right .db $08,$03,$00,$08 ; mario middle right
.db $20,$04,$00,$10 ; mario middle bottom left .db $10,$04,$00,$00 ; mario middle bottom left
.db $20,$05,$00,$18 ; mario middle bottom right .db $10,$05,$00,$08 ; mario middle bottom right
.db $28,$06,$00,$10 ; mario bottom left .db $18,$06,$00,$00 ; mario bottom left
.db $28,$07,$00,$18 ; mario bottom right .db $18,$07,$00,$08 ; mario bottom right
sprStartClearing:
.db $00
.bank 1 .bank 1
.org $FFFA .org $FFFA