TECTION.ACT

; TECTION
; TETRIS GAME IN ACTION
; (C) 2023 PAULO GARCIA

INCLUDE "D2:SYS.ACT"

DEFINE FIELD_WIDTH="12"
DEFINE FIELD_HEIGHT="18"          
DEFINE FIELD_SIZE="216" ;12 COLS 18 rows

; Global variables
CARD ARRAY tetro_i=[$0F00 $2222 $00F0 $4444],
           tetro_j=[$44C0 $8E00 $6440 $0E20],
           tetro_l=[$4460 $0E80 $C440 $2E00],
           tetro_o=[$CC00 $CC00 $CC00 $CC00],
           tetro_s=[$06C0 $8C40 $6C00 $4620],
           tetro_t=[$0E40 $4640 $4E00 $4C40],
           tetro_z=[$0C60 $4C80 $C600 $2640]

CARD POINTER curTetro
CARD POINTER nextTetro

CARD score=[0]
BYTE speed=[200]   ; smaller number, more speed

BYTE ARRAY field(FIELD_SIZE)
BYTE POINTER pField=field

BYTE ARRAY pieces=[ 0 131 129 128 'L 'O 'S 'T 'Z]


BYTE CONSOL=$D01F   ;read console keys
CHAR KEYB=$02FC  ; KEYBOARD SCAN
                 ; Z - $17, O - $8
                 ; P - $0A, L - $0


; SCREEN POINTER
CARD POINTER DLADDR ;DISPLAY LIST ADDR
BYTE POINTER SCR ; BEGINNING OF SCREEN POINTER

CARD ARRAY xTetroTemp(16)
                
; ADD CHAR ON SCREEN
PROC PUTX(CARD SCR, BYTE X, Y,V)
  POKE(SCR+(Y*40+X),V) 
RETURN

PROC CLRSCR()
  CARD I,J
  FOR I = 0 to 39
  DO
    FOR J = 0 to 23
    DO
      PUTX(SCR, I,J, 0)
    OD
  OD
RETURN

; Init playfield
; 1 borders
; 0 empty space
PROC InitField()
  BYTE x,y
                        
  FOR x=0 TO FIELD_WIDTH-1
  DO
    FOR y=0 TO FIELD_HEIGHT-1
    DO
      IF x=0 or y=FIELD_HEIGHT-1 or x=FIELD_WIDTH-1 THEN
        field(y*FIELD_WIDTH+x)=1
      ELSE
        field(y*FIELD_WIDTH+x)=0
      FI
    OD
  OD
RETURN                

PROC DrawField(BYTE x1, y1, maxY)
  CARD X,Y       
  FOR x=X1 TO X1+FIELD_WIDTH-1
  DO
    FOR Y=Y1 TO Y1+maxY
    DO
      PUTX(SCR,X,Y+3,pieces(field((y-y1)*FIELD_WIDTH+(x-x1))))
    OD
  OD
RETURN              

; Get the current random Tetro
PROC getNextTetro()
      
  BYTE randTetro

  randTetro=RAND(7)
  IF randTetro=0 THEN
    nextTetro=tetro_i
  ELSEIF randTetro=1 THEN
    nextTetro=tetro_j
  ELSEIF randTetro=2 THEN
    nextTetro=tetro_l
  ELSEIF randTetro=3 THEN
    nextTetro=tetro_o
  ELSEIF randTetro=4 THEN
    nextTetro=tetro_s
  ELSEIF randTetro=5 THEN
    nextTetro=tetro_t
  ELSEIF randTetro=6 THEN
    nextTetro=tetro_z
  FI

RETURN

; f set to 1 will record the tetro in the field - used for the ones not moving
PROC DrawTetro(CARD POINTER tetro,BYTE x,y, BYTE r, BYTE p, BYTE f)
    
  BYTE tx,ty,tt

  tx=0 ty=0
  FOR tt=0 to 15
  DO 
    IF (tetro(tt)>0) THEN
      PUTX(SCR,tx+X,ty+Y+3,pieces(p))
      IF (f=1) THEN
        ;stick tetro in the field()
        field((ty+Y)*FIELD_WIDTH+(tx+X))=3
        ;debug DrawField(FIELD_HEIGHT-1)   
      FI
    FI
    tx=tx+1
    IF tx > 3 THEN         
      ty=ty+1
      tx=0  
    fi
  OD
RETURN

; Convert Tetromino hex in binary string
PROC ExpandTetro(CARD POINTER tetro, CARD POINTER xt, BYTE r)
    
  CARD bit
  BYTE tx

  bit=$8000 
  tx=0
  WHILE bit>0 
  DO
    IF (tetro(r) & bit)>0 THEN
      xt(tx)=1
    ELSE
      xt(tx)=0
    FI
    tx=tx+1
    bit=bit RSH 1
  OD
RETURN
                
BYTE FUNC DoesFit(CARD POINTER tetro,BYTE posX, BYTE posY,BYTE r)
  BYTE px,py
  BYTE vField

  FOR px=0 TO 3
  DO
    FOR py=0 TO 3
    DO    
      ; check bounds
      if (posX+px)>=0 AND (posX+px)<FIELD_WIDTH THEN
        if (posY+py)>=0 AND (posY+py)<FIELD_HEIGHT THEN
          ;check collision
          vField = field((py+posY)*FIELD_WIDTH+(px+posX))
          if tetro(px+py*4)<>0 AND vField>0 THEN
           RETURN (0)
          fi

        fi
      fi
    OD
  OD

RETURN (1) 

PROC ShowScore()
  POSITION(21,7)
  PRINTC(score)
  ; POSITION(27,22)
  ; PRINT(" ")
RETURN

PROC ShowNextTetro()
  BYTE I,J
  FOR I = 12 to 20
  DO
    FOR J = 15 to 18
    DO
      PUTX(SCR, I,J, 0)
    OD
  OD

  DrawTetro(xTetroTemp,17,12, 0, 3, 0)

RETURN

;-------------------------
; Check complete rows
;-------------------------
BYTE FUNC CheckRows(BYTE currentY)
  BYTE px,py,dy
  BYTE empty
  BYTE I
  CARD POINTER dst,source
  BYTE rows

  rows = 0
  FOR py = currentY to FIELD_HEIGHT - 2
  Do
    empty=0
    FOR px = 1 to FIELD_WIDTH - 2
    DO
      IF field(py*FIELD_WIDTH+px)<>3 THEN
        empty=1
      FI
    OD
    if empty = 0 THEN
      ; move all rows above py one down
      rows = rows + 1
      dy = py-1
      WHILE (dy > 0)
      DO
        ; copy lines down to overwrite full row
        FOR I = 1 to FIELD_WIDTH - 2
        DO
          field((dy+1)*FIELD_WIDTH+I) = field((dy)*FIELD_WIDTH+I)
        OD
        dy = dy-1
      OD
      DrawField(0,0, FIELD_HEIGHT-1)
    fi    
  OD
  ; speed increases every X rows * 10
  speed = speed - rows * 5
  IF (speed < 0) THEN
    speed = 0
  FI
  ; score more points for multip[e rows 
  score = score + rows * 100
  ShowScore()
RETURN (1)

; Present intro screen
PROC IntroScreen()
  BYTE noInput=[1]
  BYTE I,J
  BYTE C
  
  GRAPHICS(1+16)  
  DLADDR=PEEKC(560)+4  
  SCR=DLADDR^ 
  CLRSCR()
  C=0
  POKE(756,226)
  FOR J = 0 to 23
  DO
    FOR I = 0 to 19
    DO
      PUTX(SCR, I,J,C)
      C=C+1
    OD
  OD
  WHILE noInput=1
  DO
    IF KEYB=$2F THEN ; (Q)uit
      noInput=0
    FI
  OD
  KEYB=$FF
  CLRSCR();
RETURN

;-------------------------
; Program main routine
;-------------------------
PROC Main()
  BYTE gameOver=[100] 
  BYTE currentX,currentY
  BYTE r, r1    
  BYTE debounce
  BYTE forceDown=[0] 
  Byte speedCount=[0]
  BYTE I
  
  CARD ARRAY xTetro(16)
  

  ; Initialize gr0 pointer
  
  ; IntroScreen()

  GRAPHICS(0)        
  DLADDR=PEEKC(560)+4  
  SCR=DLADDR^ 
  CLRSCR()

  POSITION(20,1)
  Print("Tection!")
  POSITION(14,2)
  Print("By PauLowRes - 2023")

  InitField()

  currentX = 6
  currentY = -2 
  r=0         
  debounce=0
  gameOver=100
  score = 0
  ; get first tetro then get next one right after
  getNextTetro()
  curTetro = nextTetro
  getNextTetro()

  
  POSITION(14,7)
  PRINT("Score: ")
  ShowScore()

  POSITION(14,13)
  PRINT("Next piece:        ")

  POSITION(28,16)
  PRINT("P - RIGHT")
  POSITION(28,17)
  PRINT("O - LEFT")
  POSITION(28,18)
  PRINT("L - DOWN")
  POSITION(28,19)
  PRINT("Z - ROTATE")

  ; expands results in string
  ExpandTetro(curTetro,xTetro, r)
  DrawField(0, 0, FIELD_HEIGHT-1)

  ; draw next tetro on the side
  ExpandTetro(nextTetro,xTetroTemp, r)
  ShowNextTetro()

  WHILE gameOver<>1
  DO

    speedCount=speedCount+1
    if (speedCount = speed) THEN
      forceDown=1
    fi
                              
    ; CHECK FOR KEYS
    if debounce=1 then
      KEYB=$FF
      debounce=0
    fi
    IF KEYB=$2F THEN ; (Q)uit
      gameOver=1
    ELSEIF KEYB=$8 and debounce=0 THEN  ; (O) LEFT
      IF DoesFit(xTetro, currentX-1,currentY,r) THEN
        DrawTetro(xTetro,currentX,currentY, r, 0, 0)
 
        currentX=currentX-1                     
      FI
      debounce=1
    ELSEIF KEYB=$A AND debounce=0 THEN  ; (P) RIGHT
      IF DoesFit(xTetro, currentX+1,currentY,r) THEN
        DrawTetro(xTetro,currentX,currentY, r, 0, 0)
        currentX=currentX+1                     
      FI
      debounce=1
    ELSEIF KEYB=0 AND debounce=0 THEN  ; (P) RIGHT
      IF DoesFit(xTetro, currentX,currentY+1,r) THEN
        forceDown=1
      FI
      debounce=1
    ELSEIF KEYB=$17 AND debounce=0 THEN ; (Z) ROTATE

      ; save previous r
      r1 = r
      r=r+1
      IF r>3 THEN
        r=0
      FI                
      ExpandTetro(curTetro,xTetroTemp, r)
      IF DoesFit(xTetroTemp, currentX,currentY,r) THEN
        
        DrawTetro(xTetro,currentX,currentY, r, 0, 0)
        ExpandTetro(curTetro, xTetro, r)
        debounce=1
      else    
        ; restore rotation
        r = r1 
      FI
    FI

    IF forceDown=1 THEN

      IF DoesFit(xTetro, currentX,currentY+1,r) THEN
        DrawTetro(xTetro,currentX,currentY, r, 0, 0)

        currentY=currentY+1
      ELSE

        IF currentY = 0 THEN
          POSITION(8,10)
          Print("**************************")
          POSITION(8,11)
          Print("*   G a m e  O v e r !   *")
          POSITION(8,12)
          Print("**************************")
          RETURN
        FI

        ; before start a new tetro
        ; copy old one onto field array
        DrawTetro(xTetro, currentX,currentY, r, 3, 1)

        ; CHECK Complete rows
        CheckRows(currentY)
 
        currentX = 5
        currentY = 0 
        r=0         
        debounce=0
        ;---getCurTetro()
        curTetro = nextTetro
        getNextTetro()
        ; expands results in string
        ExpandTetro(curTetro,xTetro, r)
        
        ExpandTetro(nextTetro,xTetroTemp, r)
        ShowNextTetro()
                     
      FI
      speedCount=0
      forceDown=0
    FI ;forceDown
    DrawTetro(xTetro, currentX,currentY, r, 3, 0)
  OD 
                  
  
RETURN