Kevan Vanderstichelen

; ___________ _____ _   _ 
;|_   _| ___ \  _  | \ | |
;  | | | |_/ / | | |  \| |
;  | | |    /| | | | . ` |
;  | | | |\ \\ \_/ / |\  |
;  \_/ \_| \_|\___/\_| \_/
; PLAYER ONE CONTROLS: WASD
; PLAYER TWO CONTROLS: 1235

define player1BikeL			$10 ; screen location of bike, low byte
define player1BikeH			$11 ; screen location of bike, high byte
define player1BikeStart 	$12 ; start of trail byte pairs
define player1BikeDirection	$02 ; direction (possible values are below)
define player1TrailLength	$03 ; trail length, in bytes
define player1Collision		$04

define player2BikeL 		$20
define player2BikeH 		$21
define player2BikeStart 	$22
define player2BikeDirection	$00
define player2TrailLength 	$01
define player2Collision		$05

define player1Points 	$04
define player2Points 	$05

define player1Color 	$07
define player2Color 	$08
define player2Temp 		$09

define maxRoundToWin 	$0a
define resetColor 		$0b

; Directions (each using a separate bit)
define movingUp      1
define movingRight   2
define movingDown    4
define movingLeft    8

; ASCII values of keys controlling the bike
define ASCII_w      $77
define ASCII_a      $61
define ASCII_s      $73
define ASCII_d      $64
define ASCII_1		$31
define ASCII_2		$32
define ASCII_3		$33
define ASCII_5		$35

; System variables
define sysRandom    $fe
define sysLastKey   $ff

;===================== INITIALIZATION ======================

lda #$01
sta player1Points

lda #$01
sta player2Points

start:
  JSR init
  JSR loop

init:
  JSR initMain
  JSR initBike
  JSR initUI
  RTS

initMain:
  LDA #15
  STA maxRoundToWin
  RTS

;----------- INITIALIZATION PLAYER 1 ----------
initBike:
  lda #movingRight  ;start direction
  sta player1BikeDirection

  lda #2  ;start length (2 segments)
  sta player1TrailLength
  
  lda #$20
  sta player1BikeL
  
  lda #$10
  sta player1BikeStart
  
  lda #$0f
  sta $14 ; trail segment 1
  
  lda #$02
  sta player1BikeH
  sta $13 ; trail segment 1
  sta $15 ; trail segment 2
  
  lda #3
  sta player1Color
  
  lda player1Points
  sta player1Points

;----------- INITIALIZATION PLAYER 2 ----------
initBike2:
  lda #movingLeft
  sta player2BikeDirection
  
  lda #2
  sta player2TrailLength
  
  lda #$7f
  sta player2BikeL
  
  lda #$10
  sta player2BikeStart
  
  lda #$0f
  sta $24
  
  lda #$05
  sta player2BikeH
  sta $23
  sta $25
  
  lda #8
  sta player2Color
  
  lda player2Points
  sta player2Points

  
  rts
;----------- USER INTERFACE INITIALIZATION ----------
initUI:
  LDX #$01
  LDY #$00

UI_Border_Loop:
  TXA
  STA $05a0,Y
  INY
  CPY #$20
  BNE UI_Border_Loop
  LDY #$00
UI_Border_Loop2:
  TXA
  STA $05e0,Y
  INY
  CPY #$20
  BNE UI_Border_Loop2
  LDY #$00

UI_PointPlayer1_Loop:
  LDA #$00
  CMP player1Points
  BEQ UI_PointPlayer2_Loop
  LDX player1Color
  TXA
  STA $05c0, Y
  INY
  CPY player1Points
  BNE UI_PointPlayer1_Loop
  
  LDA #16
  SBC player2Points
  STA player2Temp
  LDY #$00
UI_PointPlayer2_Loop:
  CLC
  LDA #$00
  CMP player2Points
  BEQ loop
  LDX #0
  TXA
  STA $05d0, Y
  INY
  CPY player2Temp
  BNE UI_PointPlayer2_Loop
UI_PointPlayer2_Loop2:
  LDX player2Color
  TXA
  STA $05d0, Y
  INY
  CPY #16
  BNE UI_PointPlayer2_Loop2
  
  jmp loop


;===================== MAIN LOOP ======================

loop:
  jsr readKeys
  jsr updateBike1
  jsr updateBike2
  jsr drawBikes
  jsr delay
  jsr checkUI
  jsr checkUI2
  jmp loop

checkUI:
  CLC
  LDA #$5
  CMP player1BikeH
  BEQ inUIzone
  RTS

inUIzone:
  CLC
  LDA #$80
  CMP player1BikeL
  BMI collisionTEMP1
  RTS

checkUI2:
  CLC
  LDA #$5
  CMP player2BikeH
  BEQ inUIzone2
  RTS

inUIzone2:
  CLC
  LDA #$80
  CMP player2BikeL
  BMI collisionTEMP2
  RTS


;===================== GET KEYS ======================
readKeys:
  lda sysLastKey
  cmp #ASCII_w
  beq upKey
  cmp #ASCII_d
  beq rightKey
  cmp #ASCII_s
  beq downKey
  cmp #ASCII_a
  beq leftKey
  cmp #ASCII_5
  beq upKey2
  cmp #ASCII_3
  beq rightKey2
  cmp #ASCII_2
  beq downKey2
  cmp #ASCII_1
  beq leftKey2
  rts
  
upKey:
  lda #movingDown
  bit player1BikeDirection
  bne illegalMove

  lda #movingUp
  sta player1BikeDirection
  rts
rightKey:
  lda #movingLeft
  bit player1BikeDirection
  bne illegalMove

  lda #movingRight
  sta player1BikeDirection
  rts
downKey:
  lda #movingUp
  bit player1BikeDirection
  bne illegalMove

  lda #movingDown
  sta player1BikeDirection
  rts
leftKey:
  lda #movingRight
  bit player1BikeDirection
  bne illegalMove

  lda #movingLeft
  sta player1BikeDirection
  rts

collisionTEMP1:
jmp collision1
collisionTEMP2:
jmp collision2

upKey2:
  lda #movingDown
  bit player2BikeDirection
  bne illegalMove

  lda #movingUp
  sta player2BikeDirection
  rts
rightKey2:
  lda #movingLeft
  bit player2BikeDirection
  bne illegalMove

  lda #movingRight
  sta player2BikeDirection
  rts
downKey2:
  lda #movingUp
  bit player2BikeDirection
  bne illegalMove

  lda #movingDown
  sta player2BikeDirection
  rts
leftKey2:
  lda #movingRight
  bit player2BikeDirection
  bne illegalMove

  lda #movingLeft
  sta player2BikeDirection
  rts

illegalMove:
  rts

;===================== UPDATE 1 ======================



updateBike1:
  inc player1TrailLength

  lda player1BikeDirection
  lsr
  bcs up
  lsr
  bcs right
  lsr
  bcs down
  lsr
  bcs left
up:
  lda player1BikeL
  sec
  sbc #$20
  sta player1BikeL
  bcc upup
  jmp trailCollision1
upup:
  dec player1BikeH
  lda #$1
  cmp player1BikeH
  beq collision1TEMP
  jmp trailCollision1
right:
  inc player1BikeL
  lda #$1f
  bit player1BikeL
  beq collision1TEMP
  jmp trailCollision1
down:
  lda player1BikeL
  clc
  adc #$20
  sta player1BikeL
  bcs downdown
  jmp trailCollision1
downdown:
  inc player1BikeH
  lda #$6
  cmp player1BikeH
  beq collision1TEMP
  jmp trailCollision1
left:
  dec player1BikeL
  lda player1BikeL
  and #$1f
  cmp #$1f
  beq collision1TEMP
  jmp trailCollision1
  
trailCollision1:
  lda #$5
  cmp player1TrailLength
  bcs back
  
  lda #$0
  ldx player1BikeL
  ldy #$03
  
  cpy player1BikeH
  bcc p1moreThan3
  
  cpy player1BikeH
  beq p1three
  cmp $0200, X
  beq back
  jmp collision1
  
p1three:
  cmp $0300, X
  beq back
  jmp collision1
  
p1moreThan3:
  ldy #$05
  cpy player1BikeH
  beq p1five
  cmp $0400, X
  beq back
  jmp collision1
  
p1five:
  cmp $0500, X
  beq back
  jmp collision1
  
 back:
  rts
  
collision1TEMP:
  jmp collision1
  
;===================== UPDATE 2 ======================
  
updateBike2:
  inc player2TrailLength

  lda player2BikeDirection
  lsr
  bcs up2
  lsr
  bcs right2
  lsr
  bcs down2
  lsr
  bcs left2
up2:
  lda player2BikeL
  sec
  sbc #$20
  sta player2BikeL
  bcc upup2
  jmp trailCollision2 
upup2:
  dec player2BikeH
  lda #$1
  cmp player2BikeH
  beq collision2
  jmp trailCollision2 
right2:
  inc player2BikeL
  lda #$1f
  bit player2BikeL
  beq collision2
  jmp trailCollision2 
down2:
  lda player2BikeL
  clc
  adc #$20
  sta player2BikeL
  bcs downdown2
  jmp trailCollision2 
downdown2:
  inc player2BikeH
  lda #$6
  cmp player2BikeH
  beq collision2
  jmp trailCollision2 
left2:
  dec player2BikeL
  lda player2BikeL
  and #$1f
  cmp #$1f
  beq collision2
  jmp trailCollision2 

trailCollision2:
  lda #$5
  cmp player2TrailLength
  bcs back2
  
  lda #$0
  ldx player2BikeL
  ldy #$03
  
  cpy player2BikeH
  bcc p1moreThan3
  cpy player2BikeH
  beq p2three
  cmp $0200, X
  beq back2
  jmp collision2
p2three:
  cmp $0300, X
  beq back2
  jmp collision2
p2moreThan3:
  ldy #$05
  cpy player2BikeH
  beq p2five
  cmp $0400, X
  beq back2
  jmp collision2
p2five:
  cmp $0500, X
  beq back2
  jmp collision2

  back2:
  rts

  
;================= UPDATE COLLISION ==================

collision1:
  INC player2Points
  INC player2Points
  CLC
  LDA maxRoundToWin
  CMP player2Points
  BMI player2Won
  jmp gameOver
 
collision2:
  INC player1Points
  INC player1Points
  CLC
  LDA maxRoundToWin
  CMP player1Points
  BMI player1Won
  jmp gameOver
  
;======================= DRAW ========================

drawBikes:
  ldx #0
  lda player1Color
  sta (player1BikeL,x) ; paint bike
  
  ldx #0
  lda player2Color
  sta (player2BikeL,x) ; paint bike
  rts


delay:
  ldx #0
spinloop:
  nop
  nop
  dex
  bne spinloop
  rts

;===================== GAME OVER ======================

player1Won:
  LDA player1Color
  STA resetColor
  JSR resetScreen
  JMP theEnd
player2Won:
  LDA player2Color
  STA resetColor
  JSR resetScreen
  JMP theEnd

gameOver:
  JSR resetScreen
  JMP start

resetScreen:
  LDX resetColor
  LDY #$00
  TXA
  STA $0200
resetScreen1:
  TXA
  STA $0201,Y
  INY
  CPY #$ff
  BNE resetScreen1
  TXA

  STA $0300
  LDY #$00
resetScreen2:
  TXA
  STA $0301,Y
  INY
  CPY #$ff
  BNE resetScreen2

  STA $0400
  LDY #$00
resetScreen3:
  TXA
  STA $0401,Y
  INY
  CPY #$ff
  BNE resetScreen3

  LDY #$00
resetScreen4:
  TXA
  STA $0500,Y
  INY
  CPY #$a0
  BNE resetScreen4

  lda #$00
  sta sysLastKey
  
  RTS

theEnd:

lda #$00
;W
sta $0364
sta $0384
sta $03a4
sta $03c4
sta $03e4
sta $0404
sta $0424
sta $0444
sta $0445
sta $0426
sta $0407
sta $0428
sta $0449
sta $044a
sta $042a
sta $040a
sta $03ea
sta $03ca
sta $03aa
sta $038a
sta $036a
;O
sta $036d
sta $038d
sta $03ad
sta $03cd
sta $03ed
sta $040d
sta $042d
sta $044d
sta $036e
sta $044e
sta $036f
sta $044f
sta $0370
sta $0450
sta $0371
sta $0451
sta $0372
sta $0392
sta $03b2
sta $03d2
sta $03f2
sta $0412
sta $0432
sta $0452
;N
sta $0455
sta $0435
sta $0415
sta $03f5
sta $03d5
sta $03b5
sta $0395
sta $0375
sta $0376
sta $0397
sta $03b7
sta $03d8
sta $03f8
sta $0419
sta $0439
sta $045a
sta $045b
sta $043b
sta $041b
sta $03fb
sta $03db
sta $03bb
sta $039b
sta $037b

Debugger

A=$00 X=$00 Y=$00
SP=$ff PC=$0600
NV-BDIZC
00110000

Monitor Start: $ Length: $

Preprocessing ...
Indexing labels ...
Found 67 labels.
Assembling code ...
Code assembled successfully, 1010 bytes.

Stopped