!**************************************************************************
!SNAKE.BAS    10/26/88
!
!by Steve Archuleta - AMUS Staff
!
!NEEDS INKEY.SBR (INKEY.M68 in [100,52])
!
!Directions:
!     The purpose of this two-player game is to move your snake across the
! road, without being run over by a car, as many times as possible. The "D"
! and "K" keys are used to move snakes 1 and 2, respectively, one lane at a
! time. Each time the road is crossed, one point is scored. If a snake is 
! run over, it will be unable to move for a short time. There is also a 
! short delay after a point has been scored to discourage players from
! continuously holding down the keys. This game is best played on a 19200
! baud terminal. The difficulty level can be changed by making the change
! described in the SQUASHED routine.
!**************************************************************************

MAP1	WAIT,F				!dummy var
MAP1	ANSWER,S,1			!continue game var
MAP1	GAME'TIME,F,6			!length of game counter
MAP1	SNAKE,S,1,"|"			!snake character
MAP1	ROAD'KILL,S,1,"*"		!smashed snake character
MAP1	LANE,F,6			!road lane (row coordinate)
MAP1	STRIPE,F,6			!road stripe (col coordinate)
MAP1	RESP,S,1			!input buffer char
MAP1	SCRMAP(21,80),F,6		!array to keep track of cars position
MAP1	SCORE1,F,6			!player 1 score
MAP1	SCORE2,F,6			!player 2 score
MAP1	DELAY1,F,6			!player 1 delay counter
MAP1	DELAY2,F,6			!player 2 delay counter
MAP1	SX1,F,6				!snake 1 coordinates
MAP1	SY1,F,6,21
MAP1	SX2,F,6				!snake 2 coordinates
MAP1	SY2,F,6,61			
MAP1	CAR1,S,8,"  [=]>"		!cars 1 - 8
MAP1	CAR2,S,16," [IIIII]>"
MAP1	CAR3,S,10,"   [==]:"
MAP1	CAR4,S,6,"    =>"
MAP1	CAR5,S,8,"{##]    "
MAP1	CAR6,S,16,":(|||||) "
MAP1	CAR7,S,10,"<*||]   "
MAP1	CAR8,S,10,"(]\\)    "
MAP1	X1,F,6  			!car coordinates 1 - 8
MAP1	Y1,F,6
MAP1	X2,F,6
MAP1	Y2,F,6
MAP1	X3,F,6
MAP1	Y3,F,6
MAP1	X4,F,6
MAP1	Y4,F,6
MAP1	X5,F,6
MAP1	Y5,F,6
MAP1	X6,F,6
MAP1	Y6,F,6
MAP1	X7,F,6
MAP1	Y7,F,6
MAP1	X8,F,6
MAP1	Y8,F,6

	? TAB(-1,29)
	? TAB(-1,0)
	? TAB(3,14)     "SSSSSSSS  NN     NN  AAAAAAAAA  KK   KK  EEEEEEEE"
	? TAB(4,14)	"SS        NNN    NN  AA     AA  KK  KK   EE"
	? TAB(5,14)	"SS        NN N   NN  AA     AA  KK KK    EE"
	? TAB(6,14)	"SSSSSSSS  NN  N  NN  AAAAAAAAA  KKK      EEEEEE"
	? TAB(7,14)	"      SS  NN   N NN  AA     AA  KK KK    EE"
	? TAB(8,14)	"      SS  NN    NNN  AA     AA  KK  KK   EE"
	? TAB(9,14)	"SSSSSSSS  NN     NN  AA     AA  KK   KK  EEEEEEEE"
      	? TAB(24,27);
      	INPUT "Press Return to Continue -> ",WAIT

START:
	CALL INITIALIZE
	CALL DRAW'ROAD
LOOP:	CALL MOVE'CARS
	CALL GETKEY
	CALL SQUASHED
	CALL UPDATE
	DELAY1 = DELAY1 - 1 : DELAY2 = DELAY2 - 1
	CALL GETKEY
	CALL SQUASHED
	CALL UPDATE
	GOTO LOOP

!*********************************************************
! INITIALIZE - Turn off cursor, clear screen, and set    *
! initial game variables.                                *
!*********************************************************
INITIALIZE:
	? TAB(-1,29)
	? TAB(-1,0)
	ON ERROR GOTO END
	GAME'TIME = 0
	SCORE1 = 0 : SCORE2 = 0
	DELAY1 = 0 : DELAY2 = 0
	SX1 = 21 : SX2 = 21		!snake starting positions
	X1 = 3 : Y1 = -1		!cars 1 - 8 starting positions
	X2 = 5 : Y2 = 0
        X3 = 7 : Y3 = -2
        X4 = 9 : Y4 = -3
        X5 = 13 : Y5 = 77
	X6 = 15 : Y6 = 73
	X7 = 17 : Y7 = 76
	X8 = 19 : Y8 = 76
	RETURN

!*********************************************************
! DRAW'ROAD - Draw initial game screen.                  *
!*********************************************************
DRAW'ROAD:
	FOR LANE = 2 TO 20 STEP 2
	 IF ((LANE <> 10) AND (LANE <> 12)) THEN &
	  FOR STRIPE = 2 TO 78 STEP 2 :&
	    ? TAB(LANE,STRIPE) "-"; :&
	  NEXT STRIPE 
 	NEXT LANE
	LANE = 11
	FOR STRIPE = 2 TO 78 STEP 2
	  ? TAB(LANE,STRIPE) "=";
	NEXT STRIPE
	? TAB(24,1) "Snake 1:";
	? TAB(24,61) "Snake 2:";
	? TAB(SX1,SY1) SNAKE;
	? TAB(SX2,SY2) SNAKE;
	RETURN

!*********************************************************
! MOVE'CARS - Move each car one position forward and     *
! update car's position via SCRMAP routine.  Note that   *
! cars have various "speeds" and that the blanks         *
! included within the cars definitions are crucial to    *
! the appearance of motion.                              *
!*********************************************************
MOVE'CARS:
	Y1 = Y1 + 2
	? TAB(X1,Y1) CAR1;
	CALL SCRMAP1
	Y2 = Y2 + 1
	? TAB(X2,Y2) CAR2;
	CALL SCRMAP2
	Y3 = Y3 + 3
	? TAB(X3,Y3) CAR3;
	CALL SCRMAP3
	Y4 = Y4 + 4
	? TAB(X4,Y4) CAR4;
	CALL SCRMAP4
	Y5 = Y5 - 4
	? TAB(X5,Y5) CAR5;
	CALL SCRMAP5
	Y6 = Y6 - 1
	? TAB(X6,Y6) CAR6;
	CALL SCRMAP6
	Y7 = Y7 - 3
	? TAB(X7,Y7) CAR7;
	CALL SCRMAP7
	Y8 = Y8 - 4
	? TAB(X8,Y8) CAR8;
	CALL SCRMAP8
	RETURN

!*********************************************************
! GETKEY - Use INKEY.SBR to retrieve next key from input *
! buffer. If "D" move snake 1; if "K" move snake 2. If   *
! snake has reached top of screen, increment score, move *
! snake to bottom and provide a short delay.             *
!*********************************************************
GETKEY: XCALL INKEY,RESP
	RESP = UCS(RESP)
	IF DELAY1 > 0 THEN GOTO SKIP1 else ? TAB(SX1,SY1) SNAKE;
	IF RESP = "D" THEN ? TAB(SX1,SY1) " "; : SX1 = SX1 -2 :&
	? TAB(SX1,SY1) SNAKE;	
	IF SX1 = 1 THEN ? TAB(SX1,SY1) " "; : SX1 = 21 : &
	? TAB(SX1,SY1) SNAKE; : SCORE1 = SCORE1 + 1 :&
	? TAB(24,10) SCORE1; : DELAY1 = 5

SKIP1:	IF DELAY2 > 0 THEN GOTO SKIP2 else ? TAB(SX2,SY2) SNAKE;
     	IF RESP = "K" THEN ? TAB(SX2,SY2) " "; : SX2 = SX2 - 2 :&
	? TAB(SX2,SY2) SNAKE;	
	IF SX2 = 1 THEN ? TAB(SX2,SY2) " "; : SX2 = 21 : &
	? TAB(SX2,SY2) SNAKE; : SCORE2 = SCORE2 + 1 :&
	? TAB(24,70) SCORE2; : DELAY2 = 5
SKIP2:	RETURN

!*********************************************************
! SQUASHED - Check to see if snake has been run over.    *
! If so, print road kill char, ding bell and set delay   *
! penalty. Otherwise, continue as normal. To make the    *
! game harder, change SX1 = SX1 + 2 to SX1 = 21. Do the  *
! same for SX2.						 *
!*********************************************************
SQUASHED:
        IF SCRMAP(SX1,SY1) = 1 THEN SX1 = SX1 + 2 :&
	? TAB(SX1,SY1) ROAD'KILL; : ? CHR(7); : DELAY1 = 15
        IF SCRMAP(SX2,SY2) = 1 THEN SX2 = SX2 + 2 :&
	? TAB(SX2,SY2) ROAD'KILL; : ? CHR(7); : DELAY2 = 15
	RETURN

!*********************************************************
! UPDATE - Check to see if cars are at end of screen.    *
! If so, erase car and set horizontal position back to   *
! start position. GAME'TIME controls the length of the   *
! game.                                                  *
!*********************************************************
UPDATE:	IF Y1 = 75 THEN Y1 = -1 : ? TAB(X1,77) "    "; :&
	GAME'TIME = GAME'TIME + 1
	IF Y2 = 72 THEN Y2 =  0 : ? TAB(X2,73) "        ";
	IF Y3 = 73 THEN Y3 = -2 : ? TAB(X3,76) "     ";
	IF Y4 = 73 THEN Y4 = -3 : ? TAB(X4,77) "  ";
	IF Y5 = 1  THEN Y5 = 77 : ? TAB(X5,1)  "    ";
	IF Y6 = 1  THEN Y6 = 73 : ? TAB(X6,1)  "        ";
	IF Y7 = 1  THEN Y7 = 76 : ? TAB(X7,1)  "     ";
	IF Y8 = 4  THEN Y8 = 76 : ? TAB(X8,4)  "     ";
	IF GAME'TIME = 10  THEN GOTO EXIT
	RETURN

!*********************************************************
! SCRMAP - Keep track of car's position on screen by     *
! filling in array. 1's indicate the presence of the     *
! car at any particular position.                        *
!*********************************************************
SCRMAP1:
	SCRMAP(X1,Y1) = 0 : SCRMAP(X1,Y1+1) = 0 : SCRMAP(X1,Y1+2) = 1
	SCRMAP(X1,Y1+3) = 1 : SCRMAP(X1,Y1+4) = 1 : SCRMAP(X1,Y1+5) = 1
	RETURN

SCRMAP2:
	SCRMAP(X2,Y2) = 0 : SCRMAP(X2,Y2+1) = 1 : SCRMAP(X2,Y2+2) = 1
	SCRMAP(X2,Y2+3) = 1 : SCRMAP(X2,Y2+4) = 1 : SCRMAP(X2,Y2+5) = 1
	SCRMAP(X2,Y2+6) = 1 : SCRMAP(X2,Y2+7) = 1 : SCRMAP(X2,Y2+8) = 1
	RETURN

SCRMAP3:		  
	SCRMAP(X3,Y3) = 0 : SCRMAP(X3,Y3+1) = 0 : SCRMAP(X3,Y3+2) = 0
	SCRMAP(X3,Y3+3) = 1 : SCRMAP(X3,Y3+4) = 1 : SCRMAP(X3,Y3+5) = 1
	SCRMAP(X3,Y3+6) = 1 : SCRMAP(X3,Y3+7) = 1