include "include/vcs.h"
include "include/macro.h"
+; TODO Implement Bird AI and gamemode where p2 can be Bird
+; implement collision
+; implement room loading where each transition takes you to a different room
+; implement level counter
+; implement lives counter
+; implement room amount to ocean based on level
+
PAL = 0
NTSC = 1
SEG.U vars
ORG $80 ; start of RAM
-PATTERN ds 1 ; storage location
FRAMECOUNT ds 1 ; animation counter location
-SPR1X ds 1 ; x pos si delay when drawing
-SPR1Y ds 1 ; y pos is scanline
-SPR2X ds 1
-SPR2Y ds 1
- SEG ; end of uninitialized segment - start of ROM binary
+Score ds 1 ; holdds 2 digit score, sotred as BCD
+Timer ds 1
+
+; digit graphic data
+
+DigitOnes ds 2 ; DigitiOnes = score, DigitOnes+1 = timer
+DigitTens ds 2
+
+; graphic data to be put into PF1
+ScoreGfx ds 1
+TimerGfx ds 1
+
+Temp ds 1
+
+; object X positions in $89-8C
+ObjectX: ds 4 ; player0, player1, missile0, missile1
+
+; object Y positions in $8D-90
+ObjectY: ds 4 ; player0, player1, missile0, missile1
+
+; DoDraw storage in $91-92
+TurtleDraw: ds 1 ; used for drawing player0
+BirdDraw: ds 1 ; used for drawing player1
+
+; DoDraw Graphic Pointer in $93-94
+TurtlePtr: ds 2 ; used for drawing player0
+BirdPtr: ds 2 ; used for drawing player1
+
+; map pointer used for map rendering
+MapPtr0: ds 2 ; used for drawing map
+MapPtr1: ds 2 ; used for drawing map
+MapPtr2: ds 2 ; used for drawing map
; ---------- Constants
SEG.U constants
TIMETOCHANGE = 20 ; speed of animation
-SPRITE1H = 16
+; height of the arena (gameplay area). Since we're using a 2 line kernel,
+ ; actual height will be twice this. Also, we're using 0-89 for the
+ ; scanlines so actual height is 180 = 90*2
+PFHEIGHT = 89 ; 180 scanlines of playfield h
NULL = 0 ; just 0
- SEG
+;===============================================================================
+; Define Start of Cartridge
+;===============================================================================
+
+ SEG CODE ; define code segment
; ----------
- ORG $F000
+ ORG $F000 ; 4k carts start at $F000
Reset
-
; clear all ram and registers
ldx #0
lda #0
Clear
- sta 0,x
- inx
- bne Clear
+ ; CLEAN_START is a macro found in macro.h
+ ; it sets all RAM, TIA registers and CPU registers to 0
+ CLEAN_START
; Init, run once only!
- lda #0
- sta PATTERN ; The binary PF 'pattern'
-
- lda #$45
- sta COLUPF ; set colour of playfield
- ldy #0 ; speed counter
-
- lda #%00000001
- sta CTRLPF ; reflect playfield
-
- ; srptie colours
- lda #$69
- sta COLUP0
- lda #$67
- sta COLUP1
; set up srptie pos
- lda #20
- sta SPR1X
- lda #15
- sta SPR1Y
-
- lda #30
- sta SPR2X
- lda #15
- sta SPR2Y
+ ldx #0
+ stx ObjectX
+ ldx #8
+ stx ObjectX+1
+ ldy #$30
+ sty ObjectY
+ sty ObjectY+1
jsr PlayIntroSong
StartOfFrame
; start of new frame
- ; start vblank processing
inc FRAMECOUNT
- lda #0
- sta VBLANK
+ jsr VerticalSync
+ jsr VerticalBlank
+ jsr Picture
+ jsr Overscan
+ jmp StartOfFrame
+VerticalSync
+ ; start vblank processing
lda #2
- sta VSYNC
-
+ ldx #49
sta WSYNC
+ sta VSYNC
+ stx TIM64T ; set timer to go off in 41 scanlines (49 * 64) / 76
+ sta CTRLPF ; D1=1, playfield now in SCORE mode
sta WSYNC
sta WSYNC ; 3 scanlines of WSYNC
lda #0
+ sta PF0
+ sta PF1
+ sta GRP0
+ sta GRP1
+ sta GRP0
+ sta WSYNC
sta VSYNC
+Sleep12 ; jsr here to sleep for 12 cycles
+ rts
+
+VerticalBlank
+ jsr PositionObjects
+ jsr SetObjectColours
+ jsr PrepScoreForDisplay
+ rts
+
+Picture
+ ; turn on display
+ sta WSYNC ; Wait for SYNC (halts CPU until end of scanline)
+ lda INTIM ; check vertical sync timer
+ bne Picture
+ sta VBLANK ; turn on the display
+
+; draw score
+ ldx #5
+scoreLoop
+ ldy DigitTens ; get the tens digit offset for the score
+ lda DigitGfx,y
+ and #$F0 ; remove the graphics for the ones digit
+ sta ScoreGfx ; and save it
+ ldy DigitOnes ; get the ones digit offset foir the score
+ lda DigitGfx,y ; use it to load the digit gfx
+ and #$0F ; remove 10s digit
+ ora ScoreGfx ; merge with tens digit and gfx
+ sta ScoreGfx ; and save it
+ sta WSYNC
+;---------------------------------------
+ sta PF1 ; update pf1 for score display
+ ldy DigitTens+1 ; get the left digit offset
+ lda DigitGfx,y ; use it to load
+ and #$F0 ; remove the gfx for the ones digit
+ sta TimerGfx ; and save it
+ ldy DigitOnes+1 ; get the ones offset from the timer
+ lda DigitGfx,y ; use it to load gfx
+ and #$0F ; remove the gfx for the tens digit
+ ora TimerGfx ; merge
+ sta TimerGfx ; and save it
+ jsr Sleep12 ; waste some cycles
+ sta PF1 ; update playfield for timer display
+ ldy ScoreGfx ; preload for next line
+ sta WSYNC ; wait for the end of scanline
+;---------------------------------------
+ sty PF1 ; update playfield for the score display
+ inc DigitTens ; advance to the next line of gfx data
+ inc DigitTens+1 ; advance to the next line of gfx data
+ inc DigitOnes ; advance to the next line of gfx data
+ inc DigitOnes+1 ; advance to the next line of gfx data
+ jsr Sleep12
+ dex ; decrease loop counter
+ sta PF1 ; update playfield
+ bne scoreLoop ; if dex != 0 then loop
+ sta WSYNC
+;---------------------------------------
+ stx PF1 ; blank out PF1 - x must be zero here!
+ sta WSYNC
+ sta WSYNC ; space between score and arena
- ; 37 scanlines of VBLANK
+ lda #1 ; 2 2
+ sta CTRLPF ; 3 5 - turn off SCORE mode and turn on REFLECT
+
+ lda #<(Room1LayoutPF0) ; store room1layout in MapPtr as a ptr
+ sta MapPtr0
+ lda #>(Room1LayoutPF0) ;
+ sta MapPtr0+1 ; store the rest in MapPtr+1
+
+ ; Do 192 scanlines of colour-changing (our picture)
+ ldy #PFHEIGHT ; draw the screen for 192 lines
+pfLoop
+ ; continuation of line 2 of the 2LK
+ ; this precalculates data that's used on line 1 of the 2LK
+ lda #TURTLEHEIGHT-1 ; height of turtle sprite - 1
+ dcp TurtleDraw ; Decrement TurtleDraw and compare with height
+ bcs DoDrawGrp0 ; if carry is set then turtle is on current scanline
+ lda #0 ; otherwise use 0 to turn off p0
+ .byte $2C ; $2C = BIT with absolute addressing, trick that
+ ; causes the lda (Turtle),y to be skipped
+DoDrawGrp0 ;
+ lda (TurtlePtr),y ; load shape
+ sta WSYNC ; wait for line
+
+ sta GRP0 ; update player0 to draw turtle
+ ldx #%11111111 ; playfiled pattern test
+ stx PF0
+ ;stx PF1
+ ;stx PF2
+
+ ; precalculate date for next line
+ lda #TURTLEHEIGHT-1 ; height of gfx
+ dcp BirdDraw ; decrement BirdDraw
+ bcs DoDrawGrp1
+ lda #0
+ .byte $2C
+DoDrawGrp1
+ lda (BirdPtr),y
+ sta WSYNC
+ ; start of line 2 of the 2LK
+ sta GRP1
ldx #0
-VerticalBlank
+ stx PF0
+ stx PF1
+ stx PF2
+ dey ; decrease the loop counter
+ bne pfLoop ; branch if more left to draw
+ rts ; return
+
+ ; 30 scanlines of overscan
+Overscan
sta WSYNC
- inx
- cpx #37
- bne VerticalBlank
+ lda #2
+ sta VBLANK
+ lda #32 ; set time for 27 scanlines 32 = ((27 * 76) / 64)
+ sta TIM64T ; timer will go off after 27 scanlines
+
+ ; game logic call
+ jsr ProcessJoystick
+
+ lda #1
+overscanLoop
+ sta WSYNC
+ lda INTIM ; check timer
+ bpl overscanLoop
+ rts
+
+ProcessJoystick
; game logic here
lda SWCHA ; input registr
asl ; test bit 0, left joy - right input
bcs Player1RightNotPressed ; this operation sets the carry for the fromer bit that fell off
; right pressed code
- ldx SPR1X
+ ldx ObjectX
inx
- stx SPR1X
+ cpx #160
+ bne SaveX ; save X if we're not at the edge
+ ldx #0 ; warp to other edge
+SaveX
+ stx ObjectX
+ ldx #1
+ stx REFP0 ; makes turtle image face right
Player1RightNotPressed
asl ; test bit 1, left joy - left input
bcs Player1LeftNotPressed
; left pressed code
- ldx SPR1X
+ ldx ObjectX
dex
- stx SPR1X
+ cpx #255 ; test for edge of screen
+ bne SaveX2
+ ldx #159 ; warp to toher side
+SaveX2
+ stx ObjectX
+ ldx #0
+ stx REFP0 ; makes turtle image face left
Player1LeftNotPressed
asl ; test bit 1, left joy - down input
bcs Player1DownNotPressed
; left pressed code
- ldx SPR1Y
- inx
- stx SPR1Y
+ ldx ObjectY
+ dex
+ cpx #255
+ bne SaveY
+ ldx #PFHEIGHT
+SaveY
+ stx ObjectY
Player1DownNotPressed
asl ; test bit 2, left joy - up input
bcs Player1UpNotPressed
; left pressed code
- ldx SPR1Y
- dex
- stx SPR1Y
-Player1UpNotPressed
-
-
-
- ; Do 192 scanlines of colour-changing (our picture)
- ldx 0
-Picture
- stx COLUBK ; ranbow effect on background
-
-PlayFieldStart
- ; set up PF to display a wall around the game field
- lda #%11111111
- sta PF0
- sta PF1
- sta PF2
-Top8LinesWall
- sta WSYNC
- inx
- cpx #8 ; line 8?
- bne Top8LinesWall ; No? Another loop
-
- ; now we change the lines
- lda #%00010000 ; PF0 is mirrored <--- direction, low 4 bits ignored
- sta PF0
- lda #0
- sta PF1
- sta PF2
-
- ; again, we don't bother writing PF0-PF2 every scanline - they never change!
- ldy #0 ; load y with 0, we use y to count sprite tables
-MiddleLinesWall
- lda #1 ; load an odd number into a
- and FRAMECOUNT ; and it with framecount to see if even or odd frame count
- ; only do sprites on even frames 0 == even 1 == odd
- cmp NULL
- beq SpriteDone
- ; sprite stuff
-SpriteStart
- cpx SPR1Y
- bcc SpriteReset
- cpy #SPRITE1H
- beq SpriteReset ; if sprites are bigger than 32, we are done!
- ; SLEEP 20
-
- lda SPR1X
-
- sec ; Set the carry flag so no borrow will be applied during the division.
-.divideby15 ; Waste the necessary amount of time dividing X-pos by 15!
- sbc #15
- bcs .divideby15
-
- sta RESP0,x
-
- lda TurtleSprite,y
- sta GRP0 ; modify sprite 0 shape
- iny
-
- jmp SpriteDone
-SpriteReset
- ; reset sprite registers to 0
- lda #0
- sta GRP0
-SpriteDone
-
- ; push y to save for later
- sta WSYNC
-
- inx
- cpx #184
- bne MiddleLinesWall
-
- ; Finally, our bottom 8 scanlines - the same as the top 8
- ; AGAIN, we aren't going to bother writing PF0-PF2 mid scanline!
-
- lda #%11111111
- sta PF0
- sta PF1
- sta PF2
-
-Bottom8LinesWall
- ; make sure sprite registers are cleared here!
- lda 0
- sta GRP0
- sta GRP1
-
- sta WSYNC
+ ldx ObjectY
inx
- cpx #192
- bne Bottom8LinesWall
-PlayFieldDone
- ; ---------------
-
- ; clear playfield first
- lda #0
- sta PF0
- sta PF1
- sta PF2
-
- lda #%01000010
- sta VBLANK ; end of screen - start blanking
-
- ; 30 scanlines of overscan
-
+ cpx PFHEIGHT+1
+ bne SaveY2
ldx #0
-Overscan
- sta WSYNC
- inx
- cpx #30
- bne Overscan
-
- jmp StartOfFrame
+SaveY2
+ stx ObjectY
+Player1UpNotPressed
+ rts
; Plays the Intro noise
PlayIntroSong
sta AUDV0
rts
-; use jsr to jump here
-; number instructions until return is passed in as y
-; destroys y
-DelayLoop
- dey
- bne DelayLoop
+SetObjectColours
+ ldx #3 ; we're going to set 4 colours
+ ldy #3 ;
+ lda SWCHB ; read the state of the console switches
+ and #%00001000 ; test state of D3, the TV Type switch
+ bne SOCloop ; if D3=1 then use colour
+ ldy #7 ; else b&w entries in table
+SOCloop
+ lda Colours,y ; get the colour or b&w value
+ sta COLUP0,x ; and set it
+ dey ; decrease y
+ dex ; decrease x
+ bpl SOCloop ; branch if positive
+ rts ; return
+
+PrepScoreForDisplay
+ ; for testing purposes, change the values in Timer and Score
+ inc Timer ; inc timer by 1
+ bne PSFDskip ; branch if not 0
+ inc Score ; inc score by 1 if Timer just rolled to 0
+PSFDskip
+ ldx #1 ; use x as the loop counter for PSFDloop
+PSFDloop
+ lda Score,x ; load A with timer or Score
+ and #$0F ; remove the tens digit
+ sta Temp ; store a into temp
+ asl ; shift left * 2
+ asl ; shfit left * 4
+ adc Temp ; add with carry in Temp * 5
+ sta DigitOnes,x ; store a in DigitOnes+1 or DigitOnes
+ lda Score,x ; load a with timer or score
+ and #$F0 ; remove the ones digit
+ lsr ; shift right / 2
+ lsr ; shift right / 2
+ sta Temp ; store a into temp
+ lsr ; shift right / 8
+ lsr ; shift right / 16
+ adc Temp ; add with carry in temp / 16 * 5
+ sta DigitTens,x
+ dex ; dec x by 1
+ bpl PSFDloop ; branch positive to loop
rts
-; This is a table that lets us divide by 15 for sprite positioning
-; -> hardcoded table is a lot faster than computing it!
-Divide15
-.POS SET 0
- REPEAT 160
- .byte (.POS / 15) + 1
-.POS SET .POS + 1
- REPEND
+PositionObjects
+ ldx #1 ; position objects 0-1: player0 and player1
+POloop
+ lda ObjectX,x ; get the object's X position
+ jsr PosObject ; set coarse X position and fine-tune amount
+ dex ; DEcrement X
+ bpl POloop ; Branch PLus so we position all objects
+ sta WSYNC ; wait for end of scanline
+ sta HMOVE ; use fine-tune values to set final X positions
+
+ ; every other frame load different animation
+ ; to get odd frames and framecount with 1
+ ;lda #0
+ ;sta Temp
+ ;lda FRAMECOUNT
+ ;and #$1
+ ;bne TurtleFrame1
+ ;jmp TurtleFrame2 ; TODO this can be made much better
+TurtleFrame1
+ ; TurtleDraw = PFHEIGHT + TURTLEHEIGHT - Y position
+ lda #(PFHEIGHT + TURTLEHEIGHT)
+ sec
+ sbc ObjectY
+ sta TurtleDraw
+
+ ; TurtlePtr = PFHEIGHT + TURTLEHEIGHT - 1 - Y position
+ lda #<(TurtleSprite + TURTLEHEIGHT - 1)
+ sec
+ sbc ObjectY
+ sta TurtlePtr
+ lda #>(TurtleSprite + TURTLEHEIGHT - 1)
+ sbc #0
+ sta TurtlePtr+1
+ jmp BirdFrame1
+
+BirdFrame1
+ ; BirdDraw = PFHEIGHT + BIRDHEIGHT - Y position
+ lda #(PFHEIGHT + BIRDHEIGHT)
+ sec
+ sbc ObjectY+1
+ sta BirdDraw
+
+ ; BirdPtr = TurtleSprite + TURTLEHEIGHT - 1 - Y position
+ lda #<(BirdSprite + BIRDHEIGHT - 1)
+ sec
+ sbc ObjectY+1
+ sta BirdPtr
+ lda #>(BirdSprite + BIRDHEIGHT - 1)
+ sbc #0
+ sta BirdPtr+1
+
+ ; use Difficulty Switches to test how Vertical Delay works
+ ldx #0
+ stx VDELP0 ; turn off VDEL for player0
+ stx VDELP1 ; turn off VDEL for player1
+ inx
+ bit SWCHB ; state of Right Difficult in N (negative flag)
+ ; state of Left Difficult in V (overflow flag)
+ bvc LeftIsB
+ stx VDELP0 ; Left is A, turn on VDEL for player0
+LeftIsB
+ bpl RightIsB
+ stx VDELP1 ; Right is A, turn on VDEL for player1
+RightIsB
+ rts
+
+ ;===============================================================================
+ ; PosObject
+ ;----------
+ ; subroutine for setting the X position of any TIA object
+ ; when called, set the following registers:
+ ; A - holds the X position of the object
+ ; X - holds which object to position
+ ; 0 = player0
+ ; 1 = player1
+ ; 2 = missile0
+ ; 3 = missile1
+ ; 4 = ball
+ ; the routine will set the coarse X position of the object, as well as the
+ ; fine-tune register that will be used when HMOVE is used.
+ ;===============================================================================
+PosObject
+ sec
+ sta WSYNC
+DivideLoop
+ sbc #15 ; 2 2 - each time thru this loop takes 5 cycles, which is
+ bcs DivideLoop ; 2 4 - the same amount of time it takes to draw 15 pixels
+ eor #7 ; 2 6 - The EOR & ASL statements convert the remainder
+ asl ; 2 8 - of position/15 to the value needed to fine tune
+ asl ; 2 10 - the X position
+ asl ; 2 12
+ asl ; 2 14
+ sta HMP0,X ; 5 19 - store fine tuning of X
+ sta RESP0,X ; 4 23 - set coarse X position of object
+ rts ; 6 29
+
+Colours
+ .byte $C6 ; green - goes into COLUP0, color for player1 and missile0
+ .byte $86 ; blue - goes into COLUP1, color for player0 and missile1
+ .byte $46 ; red - goes into COLUPF, color for playfield and ball
+ .byte $00 ; black - goes into COLUBK, color for background
+ .byte $0E ; white - goes into COLUP0, B&W for player0 and missile0
+ .byte $06 ; dark grey - goes into COLUP1, B&W for player1 and missile1
+ .byte $0A ; light grey - goes into COLUPF, B&W for playfield and ball
+ .byte $00 ; black - goes into COLUBK, B&W for background
; Sprite data
TurtleSprite
- .byte %00011000
- .byte %01100100
- .byte %11000011
- .byte %00001111
- .byte %00011001
- .byte %00110000
- .byte %00110110
- .byte %01111111
- .byte %01111111
- .byte %01111111
- .byte %01110000
- .byte %00110000
- .byte %00111000
- .byte %00011110
- .byte %00001111
- .byte %00000011
-
- .byte %00001100
- .byte %00010010
- .byte %11100011
- .byte %11111001
- .byte %11001100
- .byte %10000110
- .byte %10110110
- .byte %11111111
- .byte %11111111
- .byte %11111111
- .byte %00000111
- .byte %00000110
- .byte %00001110
- .byte %00111100
- .byte %11111000
- .byte %11100000
+ .byte %10000001
+ .byte %11000011
+ .byte %00111100
+ .byte %01111110
+ .byte %00111100
+ .byte %01111110
+ .byte %01011010
+ .byte %10000001
+TURTLEHEIGHT = * - TurtleSprite
+
+TurtleSprite2
+ .byte %01000010
+ .byte %11000011
+ .byte %00111100
+ .byte %00111100
+ .byte %00111100
+ .byte %01111110
+ .byte %01011010
+ .byte %01000010
+TURTLEHEIGHT2 = * - TurtleSprite2
+
+BirdSprite
+ .byte %00000000
+ .byte %10011001
+ .byte %01011010
+ .byte %10100101
+ .byte %10011001
+ .byte %00011000
+ .byte %00011000
+ .byte %00100100
+BIRDHEIGHT = * - BirdSprite
+
+ align 256
+DigitGfx:
+ .byte %01110111
+ .byte %01010101
+ .byte %01010101
+ .byte %01010101
+ .byte %01110111
+
+ .byte %00010001
+ .byte %00010001
+ .byte %00010001
+ .byte %00010001
+ .byte %00010001
+
+ .byte %01110111
+ .byte %00010001
+ .byte %01110111
+ .byte %01000100
+ .byte %01110111
+
+ .byte %01110111
+ .byte %00010001
+ .byte %00110011
+ .byte %00010001
+ .byte %01110111
+
+ .byte %01010101
+ .byte %01010101
+ .byte %01110111
+ .byte %00010001
+ .byte %00010001
+
+ .byte %01110111
+ .byte %01000100
+ .byte %01110111
+ .byte %00010001
+ .byte %01110111
+
+ .byte %01110111
+ .byte %01000100
+ .byte %01110111
+ .byte %01010101
+ .byte %01110111
+
+ .byte %01110111
+ .byte %00010001
+ .byte %00010001
+ .byte %00010001
+ .byte %00010001
+
+ .byte %01110111
+ .byte %01010101
+ .byte %01110111
+ .byte %01010101
+ .byte %01110111
+
+ .byte %01110111
+ .byte %01010101
+ .byte %01110111
+ .byte %00010001
+ .byte %01110111
+
+ .byte %00100010
+ .byte %01010101
+ .byte %01110111
+ .byte %01010101
+ .byte %01010101
+
+ .byte %01100110
+ .byte %01010101
+ .byte %01100110
+ .byte %01010101
+ .byte %01100110
+
+ .byte %00110011
+ .byte %01000100
+ .byte %01000100
+ .byte %01000100
+ .byte %00110011
+
+ .byte %01100110
+ .byte %01010101
+ .byte %01010101
+ .byte %01010101
+ .byte %01100110
+
+ .byte %01110111
+ .byte %01000100
+ .byte %01100110
+ .byte %01000100
+ .byte %01110111
+
+ .byte %01110111
+ .byte %01000100
+ .byte %01100110
+ .byte %01000100
+ .byte %01000100
+
+; the room table holds pf information for each 1/2 scanline as a byte. 89 bytes
+; All rooms require PF1 and PF2 tables as well
+Room1LayoutPF0
+ .byte %11111111
+ .byte %01111100
+ .byte %01000111
+ .byte %11111111
;------------------------------------------------------------------------------
- ORG $FFFA
+ ORG $FFFA ; set address to 6507 Interrupt Vectors
+ ;===============================================================================
+ ; Define End of Cartridge
+ ;===============================================================================
InterruptVectors
.word Reset ; NMI
.word Reset ; RESET
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