My template only has a few running lines of code and I still believe they're very wasteful. For example:
Code: Select all
INFLOOP: ;every JMP sets PC (program counter)
LDA $01
BNE READINPUT1 ;one input per frame
JMP INFLOOP ;wait for NMI
READINPUT1:
LDA #$01
STA $4016 ;write 1 then 0 bit to 4016, then pull it out one bit at a time
LSR ;LSR=1 byte, LDA=2 byte
STA $4016 ;4016 player 1, 4017 player 2
LDX #$08 ;start the cycle
READINPUT2:
ASL $02 ;free the rightmost bit
LDA $4016
AND #$03 ;A=A*0000 0011 (to pure it out)
ORA $02 ;A=A+$02
STA $02 ;$02=A
DEX
BNE READINPUT2 ;Z=1 go down
LDA #$00
STA $01
JSR PLAYER1CONTROL
JSR PLAYER1OUTPUT
JMP INFLOOP
PLAYER1OUTPUT:
LDA $10 ;Y coordinate
CPX #28 ;left move frame #2
BEQ :+
CPX #08 ;right move frame #2
BEQ :+
CLC
SBC #$00
: STA $0210 ;Upper half Y
STA $0214
CLC
ADC #$08
STA $0218 ;Lower half Y
STA $021C
LDA $11 ;X coordinate
STA $0213 ;Left half X
STA $021B
ADC #$08
STA $0217 ;Right half X
STA $021F
LDY #$00
: LDA PLAYER_SPRITE_TILES, X
STA $0211, Y ;Player 1, sprite tiles
LDA $12
STA $0212, Y ;Player 1, sprite attributes
INX
INY
INY
INY
INY
CPY #$10
BNE :-
RTS
PLAYER1CONTROL: ;ABCD^v<>
LDA $03
BEQ :+ ;if Z=1 go down
JMP PLAYER1FIRE2
: LDA $02 ;read player 1 input
TAX
AND #%01000000
BNE :++ ;if Z=1 go down
TXA
AND #%00000011 ;if (Right OR Left)
BEQ :+++ ;if Z=0 go down
LSR
BNE :+ ;if Z=1 go down
JMP PLAYER1RIGHT
: JMP PLAYER1LEFT
: JMP PLAYER1FIRE1
: JMP PLAYER1IDLE
PLAYER1IDLE:
LDA #$00
STA $13 ;animation frames
LDA $12 ;character sprite attributes
AND #%01000000 ;#$40 = flip horizontal
BNE :+ ;if Z=1 go down
LDX #0 ;right idle
RTS
: LDX #20 ;left idle
RTS
PLAYER1RIGHT:
INC $13 ;frame timer virtual register
LDA $12
AND #%00000011
STA $12 ;sprite direction attribute
INC $11 ;Player X++
LDA $13
CMP #8
BPL :+ ;if N=0 go down
LDX #4 ;right move rifle frame 1
RTS
: CMP #16
BPL :+
LDX #8 ;right move rifle frame 2
RTS
: CMP #24
BPL :+
LDX #12 ;right move rifle frame 3
RTS
: CMP #32
BPL :+
LDX #16 ;right move rifle frame 4
RTS
: LDA #$FF ;null frame
STA $13
LDX #4
RTS
PLAYER1LEFT:
INC $13 ;animation frame virtual register
LDA $12
ORA #%01000000
STA $12
DEC $11 ;Player X--
LDA $13 ;animation frames
CMP #$08
BPL :+ ;if N=0 go down
LDX #24
RTS
: CMP #$10
BPL :+
LDX #28
RTS
: CMP #$18
BPL :+
LDX #32
RTS
: CMP #$20
BPL :+
LDX #36
RTS
: LDA #$FF ;null frame
STA $13
LDX #24
RTS
PLAYER1FIRE1: ;animation has to be locked until the first or second shot is complete
INC $03 ;lock animation
LDA #$FF
STA $13 ;animation frame virtual register
PLAYER1FIRE2:
INC $13
LDA $12 ;character sprite attributes
AND #%01000000 ;#$40 = flip horizontal
BNE :+++ ;if Z=1 go down
;RIGHT
LDA $13 ;animation frames
CMP #5
BPL :+ ;if N=0 go down
JSR PLAYER1FIRE
LDX #0 ;right idle
RTS
: CMP #10
BPL :+
LDA #$FF ;disable sprite by invalid Y
STA $020C
LDX #40 ;right shoot
RTS
: LDX #0 ;right idle
LDA #$FF ;disable sprite by invalid Y
STA $020C
LDA #0
STA $13
STA $03
RTS
;LEFT
: LDA $13 ;animation frames
CMP #5
BPL :+ ;if N=0 go down
JSR PLAYER1FIRE
LDX #20 ;left idle
RTS
: CMP #10
BPL :+
LDA #$FF ;disable sprite by invalid Y
STA $020C
LDX #44 ;left shoot
RTS
: LDX #20 ;left idle
LDA #$FF ;disable sprite by invalid Y
STA $020C
LDA #0
STA $13
STA $03
RTS
PLAYER1FIRE:
TAX
LDA $10 ;player Y
CLC
ADC #3
STA $020C ;sprite Y, fire
LDA #$1E
STA $020C+1 ;sprite tile
LDA $12
STA $020C+2 ;sprite attribute
AND #$40
BNE :+
LDA $11 ;RIGHT
CLC
ADC #$10
STA $020C+3
TXA
RTS
: LDA $11 ;LEFT
CLC
SBC #$07
STA $020C+3
TXA
RTS
NMI: ;PPU says graphics are done and orders to finish it up whatever you're currently doing
LDA #$02 ;load sprite range
STA $4014
LDA #$01
STA $01 ;frame complete = true
RTI ;return back from interrupt, directed by x2-byte address in Stack Memory (usually closer to 01FF-0100)
PLAYER_SPRITE_TILES: ;Player character metasprite
.byte $10, $11, $12, $13 ;frame 1 Facing right, Idle, Rifle #0
.byte $10, $11, $14, $15 ;frame 2 Facing right, Move, Rifle
.byte $10, $11, $16, $17 ;frame 3
.byte $10, $11, $18, $19 ;frame 4
.byte $10, $11, $1A, $1B ;frame 5
.byte $11, $10, $13, $12 ;frame 6 Facing left, Idle, Rifle #20
.byte $11, $10, $15, $14 ;frame 7 Facing left, Move, Rifle
.byte $11, $10, $17, $16 ;frame 8
.byte $11, $10, $19, $18 ;frame 9
.byte $11, $10, $1B, $1A ;frame 10
.byte $10, $11, $1C, $1D ;frame 11 Facing right, Fire, Rifle #40
.byte $11, $10, $1D, $1C ;frame 12 Facing left, Fire, Rifle #44
. BUT, The game engine is mostly ready, I can just draw for now, add textboxes when I want, add current ennemies. Still got about 150KB avail.= for levels and other item upgrades and more dmc sounds!!!!!!
