joyas.bas

'-------------------------------------
' Joyas: A match-three pieces game
'

' Character set redefinition
data charset() b. = $D0,$68,$34,$68,$D0,$68,$34,$68, ' 1: Wall 1
data           b. = $16,$2C,$58,$2C,$16,$2C,$58,$2C, ' 2: Wall 2
data           b. = $00,$18,$68,$44,$2C,$30,$00,$00, ' 3: Rotated square
data           b. = $00,$10,$38,$6C,$38,$10,$00,$00, ' 4: Diamond
data           b. = $00,$7C,$54,$7C,$54,$7C,$00,$00, ' 5: Filled Square
data           b. = $00,$64,$2C,$10,$68,$4C,$00,$00, ' 6: Cross
data           b. = $00,$38,$4C,$5C,$7C,$38,$00,$00, ' 7: Big ball
data           b. = $00,$5C,$40,$54,$04,$74,$00,$00, ' 8: Flag?
data           b. = $00,$00,$00,$00,$00,$00,$00,$00, ' 9: Explosion
data           b. = $7C,$82,$82,$82,$82,$82,$7C,$00, '10: Cursor
data           b. = $D1,$6A,$35,$1B,$0E,$04,$00,$00, ' B: Bottom-left
data           b. = $11,$AA,$55,$BB,$EE,$44,$00,$00, ' C: Bottom
data           b. = $16,$AC,$58,$B0,$E0,$40,$00,$00  ' D: Bottom-right

data explode() b. = $00,$00,$00,$38,$54,$38,$00,$00,
data           b. = $00,$00,$24,$40,$12,$08,$44,$00,
data           b. = $00,$42,$00,$80,$00,$01,$00,$82,
data           b. = $00,$00,$00,$00,$00,$00,$00,$00

' Our board pieces:
data pieces() b. = $03, $44, $85, $C6, $07, $48

' Our empty board (two lines)
data eboard() b. = $80,$40,$81,$09,$09,$09,$09,$09,$09,$09,$09,$09,$09,$82,$40,$80,
data          b. = $40,$80,$81,$09,$09,$09,$09,$09,$09,$09,$09,$09,$09,$82,$80,$40
data lboard() b. = $80,$40,$8B,$8C,$8C,$8C,$8C,$8C,$8C,$8C,$8C,$8C,$8C,$8D,$40,$80

' Set graphics mode and narrow screen
graphics 18
poke 559, 33

' Redefine character set
move $E000, $7C00, 512
move adr(charset), $7C08, 104
poke 756, $7C

' Set colors
if peek($d014) = 1
 ' PAL
 se. 0,3,8
 se. 1,11,10
 se. 2,8,6
 se. 3,14,14
else
 ' NTSC
 se. 0,4,8
 se. 1,12,10
 se. 2,9,6
 se. 3,2,14
endif

' Array to hold the board, cleared on DIM
dim board(192) byte
mainBoard = adr(board) + 19
fullBoard = adr(board) + 16

hiScore = 0
screen = dpeek(88)
screenBoard = screen + 3
C = mainBoard - screenBoard

' Loop forever
do

 ' Clear board
 for i=0 to 4
  move adr(eboard), fullBoard+i*32, 32
 next i

 ' Init game variables
 score = 0     ' Score
 nmoves = 15   ' Remaining moves
 addMove = 16  ' Points to bonus
 crsPos = 0    ' Cursor pos

 ' Clear the screen
 mset screen, 176, 0
 position 0, 0

 ' Show game info
 print #6, , , " joyas", , , "HI SCORE:"; hiScore
 print #6, "BUTTON: game    ANY KEY: exit"

 ' Wait for button press and release
 repeat : until not strig(0) or key()
 repeat : until strig(0) or key()

 ' Exit on any key pressed
 if key() then end

 ' Disable attract mode
 poke 77,0
 ' Draw bottom of board
 move adr(lboard), screen+160, 16

 ' Call game loop
 while nmoves > 0
  @GameLoop
 wend

 if hiScore < score then hiScore = score

loop

'-------------------------------------
' Move the cursor and wait for play
proc MoveCursor

 ' Loop
 do
  ' Disable attract mode
  poke 77,0

  ' Wait for valid move
  repeat
   ' Show cursor
   poke crsPos+screenBoard, 192+10
   pause 1
   ' Remove cursor
   poke crsPos+screenBoard, peek(crsPos+mainBoard)
   pause 1
   ' Move cursor
   i = stick(0)
   nxtPos = (i=7) - (i=11) + 16 * ((i=13) - (i=14)) + crsPos
  until nxtPos <> crsPos and peek(nxtPos + mainBoard) & 63 > 2

  ' If button is pressed, return
  if not strig(0) then Exit

  ' Move cursor
  crsPos = nxtPos
 loop

endproc


'-------------------------------------
' Make pieces fall in the board
proc FallPieces

 ' Move board to screen
 move fullBoard, screen, 160

 ' Search for holes in the board
 for A=mainBoard to mainBoard + 151 step 16
  for P=A to A+9
   if peek(P) & 63 = 9
    ' If we found a hole, fall pieces!
    i = P
    while i > mainBoard + 15
     poke i, peek(i-16)
     i = i-16
    wend
    ' Set new piece and display current position
    poke i, pieces(rand(6))
    move fullBoard, screen, 160
   endif
  next P
 next A

endproc

'-------------------------------------
' Search matching pieces and remove
proc MatchPieces

 ' Number of matches found
 lsize = 0

 ' Go through each line
 for A = screenBoard to screenBoard + 151 step 16
  ' And through each column
  for X=A to A+9
   P = peek(X)
   ' Test if equal to the next two pieces
   if P = peek(X+1) and P = peek(X+2)
    ' Transform screen pointer to board pointer
    Y = X + C
    ' Clean the three pieces found
    PC = (P & 192) + 9
    poke Y, PC
    poke Y+1, PC
    poke Y+2, PC
    inc lsize
   endif

   ' Test if equal to the two pieces bellow
   IF P = peek(X + 16) and P = peek(X + 32)
    ' Transform screen pointer to board pointer
    Y = X + C
    ' Clean the three pieces found
    PC = (P & 192) + 9
    poke Y, PC
    poke Y + 16, PC
    poke Y + 32, PC
    inc lsize
   endif
  next X
 next A

 if lsize
  ' Found a line, add to score and show a little animation
  score = score + lsize * lsize
  move fullBoard, screen, 160

  for i = 0 to 3
   sound 1, 80, 0, 10 - i * 3
   ' Set animation frame
   move i*8 + adr(explode), $7C48, 8
   pause 4
  next i
 endif

 ' Add one move at 16, 32, 64, etc. points
 if score >= addMove
  inc nmoves
  addMove = addMove * 2
 endif

 ' Print current score and moves left
 position 18, 8
 print #6, "score "; score; "/"; nmoves,
 sound

endproc

'-------------------------------------
' Our main game loop
proc GameLoop

 ' Update number of moves
 dec nmoves

 ' Loop until no pieces are left to move
 repeat
  @FallPieces
  @MatchPieces
 until not lsize

 ' Game over if no more moves
 if nmoves < 1 then exit

 @MoveCursor

 ' Perform an exchange
 poke crsPos + mainBoard, peek(nxtPos + screenBoard)
 poke nxtPos + mainBoard, peek(crsPos + screenBoard)
 sound 0, 100, 10, 10
 pause 2
 sound

endproc