So, I got my supercharger mojo working...(though I still need to rearrange my workspace:PC's to my left, TV to my right, Atari at my feet. And I can't
watch tv or have PC sounds while I'm doing the supercharger thing.
Have people been able to isolate the potential "gotchas" of using a supercharger to test your code? I think I've heard some 2K and 4K
images have problems, but I don't know if there's something a homebrewer
can do to make it more or less likely to work via the supercharger.
But I had a bigger problem: my code doesn't work on the real thing,
dang it. It works great on StellaX and Z26 (!) but not via the supercharger,
and not on PCAE (though it breaks differently on PCAE)
Here's the code. It's still pretty small, and I thought straightforward.
Could anyone who feels so inclined take a look? (You can get the bin
from the game's website at
http://alienbill.com/joustpong/
--SNIP--
; yet another moving dot by Kirk Israel
processor 6502
include vcs.h
org $F000
P0YPosFromBot = $80
P0VisibleLine = $81
P0DrawBuffer = $82
P0VertSpeed = $83
P1YPosFromBot = $84
P1VisibleLine = $85
P1DrawBuffer = $86
P1VertSpeed = $87
But0WasOn = $88
But1WasOn = $8A
GravTimer = $8B
;CONSTANTS
FlapStrength = #4;
GravDelay = #6 ;How often does gravity pull 'em down?
MaximumSpeed = #6
;generic start up stuff...
Start
SEI
CLD
TXS
LDX #$FF
LDA #0
ClearMem
STA 0,X
DEX
BNE ClearMem
LDA #$00
STA COLUBK
;Some other initialization
LDA GravDelay
STA GravTimer ;initialize gravity timer (only 1 in N ticks do we pull)
LDA #33
STA COLUP0 ;Set P0 Reddish
LDA #66
STA COLUP1 ;Set P1 Purplish
LDA #120
STA P0YPosFromBot ;P0 Initial Y Position
STA P1YPosFromBot ;P1 Initial Y Position
LDA #0
STA P0VertSpeed
STA P1VertSpeed
;VSYNC time
MainLoop
LDA #2
STA VSYNC
STA WSYNC
STA WSYNC
STA WSYNC
LDA #43
STA TIM64T
LDA #0
STA VSYNC
CheckButton0
LDA INPT4
BMI NoButton0
;Check to see if the button was already down
LDA But0WasOn
BNE Button0WasAlreadyDown
;New Button Pressed Time to Flap!
LDA P0VertSpeed
SEC
SBC FlapStrength
STA P0VertSpeed
LDA #1
STA But0WasOn
Button0WasAlreadyDown
JMP EndButton0
NoButton0 ;button wasn't pressed, remember that
LDA #0
STA But0WasOn
EndButton0
CheckButton1
LDA INPT5
BMI NoButton1
;Check to see if the button was already down
LDA But1WasOn
BNE Button1WasAlreadyDown
;New Button Pressed Time to Flap!
LDA P1VertSpeed
SEC
SBC FlapStrength
STA P1VertSpeed
LDA #1
STA But1WasOn
Button1WasAlreadyDown
JMP EndButton1
NoButton1 ;button wasn't pressed, remember that
LDA #0
STA But1WasOn
EndButton1
;Time to Add Gravity to Speeds of P0/P1?
DEC GravTimer
BNE DoneWithGravity
INC P0VertSpeed
INC P1VertSpeed
LDA GravDelay
STA GravTimer
DoneWithGravity
; LDA P0YPosFromBot
; STA COLUBK
;Move the Players first, then check if hit ceiling/floor
;
;
;Add the negative of the Player 0 Vert Speed to 0 in A
LDA #0
SEC
SBC P0VertSpeed
;Then add the current position of p0
CLC
ADC P0YPosFromBot
STA P0YPosFromBot
;Add the negative of the Player 1 Vert Speed to 0 in A
LDA #0
SEC
SBC P1VertSpeed
;Then add the current position p1
CLC
ADC P1YPosFromBot
STA P1YPosFromBot
;check if player 0 hit floor
LDA #10 ;10 is floor
CLC
CMP P0YPosFromBot
BCC DoneCheckingHitFloorP0
;we need a better bounce routine, like reducing the speed?
;speed should be positve; let's divide it my two and then
;subtract it from zero to get the new speed (i.e. a half rebound)
LDA P0VertSpeed
CLC
ROR
STA P0VertSpeed
LDA #0
SEC
SBC P0VertSpeed
STA P0VertSpeed
LDA #10
STA P0YPosFromBot ;putplayer on floor
DoneCheckingHitFloorP0
;check if player 1 hit floor
LDA #10 ;10 is floor
CLC
CMP P1YPosFromBot
BCC DoneCheckingHitFloorP1
;we need a better bounce routine, like reducing the speed?
;speed should be positve; let's divide it my two and then
;subtract it from zero to get the new speed (i.e. a half rebound)
LDA P1VertSpeed
CLC
ROR
STA P1VertSpeed
LDA #0
SEC
SBC P1VertSpeed
STA P1VertSpeed
LDA #10
STA P1YPosFromBot ;putplayer on floor
DoneCheckingHitFloorP1
;check if player 0 hit ceiling - full rebound
LDA #180
CMP P0YPosFromBot
BCS DoneCheckingHitCeilingP0
LDA #0;
SBC P0VertSpeed
STA P0VertSpeed
LDA #180
STA P0YPosFromBot
DoneCheckingHitCeilingP0
;check if player 1 hit ceiling - full rebound
LDA #180
CMP P1YPosFromBot
BCS DoneCheckingHitCeilingP1
LDA #0;
SBC P1VertSpeed
STA P1VertSpeed
LDA #180
STA P1YPosFromBot
DoneCheckingHitCeilingP1
;assum horiz movement will be zero
LDX #$00
LDA #$40 ;Left?
BIT SWCHA
BNE SkipMoveLeftP0
LDX #$10
LDA %00001000
STA REFP0 ;show reflected version
SkipMoveLeftP0
LDA #$80 ;Right?
BIT SWCHA
BNE SkipMoveRightP0
LDX #$F0
LDA %00000000
STA REFP0
SkipMoveRightP0
STX HMP0 ;set horiz movement for player 0
;assum horiz movement will be zero
LDX #$00
LDA #$04 ;Left?
BIT SWCHA
BNE SkipMoveLeftP1
LDX #$10
LDA %00001000
STA REFP1
SkipMoveLeftP1
LDA #$08 ;Right?
BIT SWCHA
BNE SkipMoveRightP1
LDX #$F0
LDA %00000000
STA REFP1
SkipMoveRightP1
STX HMP1 ;set horiz movement for player 0
WaitForVblankEnd
LDA INTIM
BNE WaitForVblankEnd
LDY #191
STA VBLANK
STA WSYNC
STA HMOVE
;main scanline loop...
ScanLoop
STA WSYNC
LDA P0DrawBuffer
STA GRP0
LDA P1DrawBuffer
STA GRP1
; here the idea is that P0VisibleLine
; is zero if the line isn't being drawn now,
; otherwise it's however many lines we have to go
CheckActivatePlayer0
CPY P0YPosFromBot
BNE SkipActivatePlayer0
LDA #8 ;8 lines tall
STA P0VisibleLine
SkipActivatePlayer0
;turn player off then see if it should be on
LDA #00
;
;if the P0VisibleLine is non zero,
;we're drawing it
;
LDX P0VisibleLine
BEQ FinishPlayer0
IsPlayer0On
LDA BigHeadGraphic-1,X
DEC P0VisibleLine
FinishPlayer0
STA P0DrawBuffer
; here the idea is that P1VisibleLine
; is zero if the line isn't being drawn now,
; otherwise it's however many lines we have to go
CheckActivatePlayer1
CPY P1YPosFromBot
BNE SkipActivatePlayer1
LDA #8 ;8 lines tall
STA P1VisibleLine
SkipActivatePlayer1
;turn player off then see if it should be on
LDA #00
;
;if the P0VisibleLine is non zero,
;we're drawing it
;
LDX P1VisibleLine
BEQ FinishPlayer1
IsPlayer1On
LDA BigHeadGraphic-1,X
DEC P1VisibleLine
FinishPlayer1
STA P1DrawBuffer
;now just finish counting of scanloop
DEY
BNE ScanLoop
LDA #2
STA WSYNC
STA VBLANK
LDX #30
OverScanWait
STA WSYNC
DEX
BNE OverScanWait
JMP MainLoop
org $FF00
BigHeadGraphic
.byte %00111100
.byte %01111110
.byte %11000001
.byte %10111111
.byte %11111111
.byte %11101011
.byte %01111110
.byte %00111100
org $FFFC
.word Start
.word Start
;;;;THE JUNKYARD
;;See if we're going too darn fast
; LDA MaximumSpeed
; SEC
; ;;;;SBC MaximumSpeed ; Maximum Speed
;
; CMP P0VertSpeed
; BCS SpeedNotMaxxed
;
;
;; BMI SpeedNotMaxxed ;if speed - maxspeed is positive, we need to slow down
; LDA MaximumSpeed
; STA P0VertSpeed
;
;SpeedNotMaxxed
--SNIP--
--
KirkIsrael@xxxxxxxxxxxxx http://kisrael.com
MISTAKES "It could be that the purpose of your life is
only to serve as a warning to others."
--Demotivators, http://www.despair.com
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