Snake TMCD677 (tvgames.me) Locomotive BASIC v1.1 PUR-120 Introduction ------------ My first attempt at writing a complete game limited to 10 Lines. Chosen Locomotive BASIC (Amstrad CPC) for auld lang syne. Pretty simple game many will remember from their old Nokia mobile phones in the early 2000's. Code is under 800 characters but a couple of lines squeek over 80 characters hence PUR-120. Game would easily be PUR-80 in just about anyother 8-bit dialect. Loading ------- The provided DSK image contains 8 versions of the game (most not working). Insert the disk into your favourite Amstrad CPC Emulator and execute: LOAD"Snake8 RUN In either CPC664 or CPC6128 modes. The recomended emulator is CaPriCe Forever by Fredouille and can be downloaded from the CPC Power website (https://www.cpc-power.com/cpcarchives/index.php?page=articles&num=445). Controls -------- Please make sure your keyboard is in lowercase mode (default) prior to running the game. UP - 'p' DOWN - 'l' LEFT - 'z' RIGHT - 'x' Instructions ------------ The game starts with a small single segment snake in the centre of the screen automatically moving to the left. Your task is to guide this snake around the screen eating numbers that will appear randomly around the screen. Each time you eat a number your snakes body will grow by that number of segments. However you need to be careful. The snake cannot move beyond the edges of the screen or cross its own path. Hit the edge of the screen or the growing body of the snake and it's GAME OVER! Beware - the top of the screen is at Line2, below the score line. Also, each time you eat a number the snakes movement will speed up by that amount. When the game ends press any key to return to Locomotive BASIC and execute: RUN for another game. Scoring ------- Snake is a high score challenge game. Who lasts the longest and eats the most numbers gets the highest score and wins. You score 10pts each time the snake moves and the value of any numbers the snake eats. Disk Catalogue -------------- Snake1.BAS - Original 5 line concept test moving snake body around screen Snake2.BAS - 1st attempt long listing; snake doesn't move; numbers appear randomly Snake3.BAS - 10Liner version of Snake2 Snake4.BAS - 10Liner. Displays snake head, first random number, then hits GAME OVER Snake5.BAS - Full anotated listing. Random numbers and snake growth are broken Snake6.BAS - Fully working game, final full anotated listing - see listin below Snake7.BAS - Fully working game. Snake 6 condensed. REM statments removed and variable names shortened Snake8.BAS - 10Liner. Fully working game. Final fully working entry - see listing below Fully Anotated Listing ---------------------- 10 REM VARIABLES 20 DIM path(500,2) : REM snake body path co-ordinates stack 30 LET tsp=1 : REM tail stack pointer 40 LET hsp=1 : REM head stack pointer 50 LET x=10 : REM head x-axis co-ordinate 60 LET y=10 : REM head y-axis co-ordinate 70 LET i$="" : REM user input 80 LET score=-10 : REM player score 90 LET grow=0 : REM amount to grow snake by 100 LET c$="" : REM screen content 110 LET w=750 : REM wait time, snake speed 120 LET n=0 : REM random number 130 LET d$="z" : REM current direction 140 LET nx=0 : REM random number x-axis co-ordinate 150 LET ny=0 : REM random number y-axis co-ordinate 160 LET temp$="" : REM screen contents 170 LET flag=1 : REM random number display flag 200 REM SET-UP 210 MODE 0 : REM 20 characters x 25 lines 220 INK 0,1 : REM background colour (blue) 230 INK 1,24 : REM snake colour (yellow) 240 INK 2,26 : REM score colour (white) 250 INK 3,6 : REM number colour (red) 260 INK 4,6,26 : REM game over colour (flashing red+white) 300 REM START GAME LOOP 310 LET path(hsp,1)=x : REM store head x-axis in stack 320 LET path(hsp,2)=y : REM store head y-axis in stack 330 LET hsp=hsp+1 : REM increase head stack pointer 340 IF hsp>500 THEN hsp=1 : REM if head stack point at end of stack move to start 500 REM DISPLAY 510 LOCATE x,y : REM goto new head position 520 PEN 1 : REM use yellow ink 530 PRINT "*"; : REM display snake head 540 LET score=score+10 : REM add 10 to score for each move 550 PEN 2 : REM use white ink 560 LOCATE 12,1 : REM goto score display position 570 PRINT score; : REM update score 580 FOR s=1 TO w:NEXT s : REM wait for snake speed 590 IF grow<>0 THEN LET grow=grow - 1 ELSE LOCATE path(tsp,1),path(tsp,2):PRINT " ";:LET tsp=tsp+1:IF tsp>500 THEN LET tsp=1 595 REM if snake not growing then remove body from current tail position 700 REM USER INPUT AND MOVEMENT 710 LET i$=INKEY$ : REM get user input 720 IF i$<>"" THEN LET d$=i$ : REM if input detected update direction 730 IF d$="z" THEN LET x=x-1 : REM if user presses "z" move left 740 IF d$="x" THEN LET x=x+1 : REM if user presses "x" move right 750 IF d$="p" THEN LET y=y-1 : REM if user presses "p" move up 760 IF d$="l" THEN LET y=y+1 : REM if user presses "l" move down 800 REM COLLITION DETECTION 810 IF x<1 OR x>20 OR y<2 OR y>25 THEN GOTO 1000 815 REM end game if hit edge of screen 820 LOCATE x,y : REM goto next head position 830 LET temp$=COPYCHR$(#0) : REM get any characters currently at that position 840 IF temp$="*" THEN GOTO 1000: REM end game if snake head touches body 850 IF temp$<>" " THEN LET grow=n:LET score=score+n:LET w=w-n:LET flag=1 855 REM if head finds number add to score and grow snake 900 REM RANDOM NUMBERS 910 IF flag=0 THEN GOTO 300 : REM if not collected next number 920 LET n=INT((RND(1)*9)+1) : REM choose a random numner (1..9) 930 LET nx=INT((RND(1)*20)+1) : REM choose random x co-ordinate for random number 940 LET ny=INT((RND(1)*25)+1) : REM choose random y co-ordinate for random number 950 IF ny=1 THEN GOTO 930 : REM if y-cordinate on score line choose another 960 LOCATE nx,ny : REM goto chosen random number position 970 LET temp$=COPYCHR$(#0) : REM get any characters already there 980 IF temp$="*" THEN GOTO 930 : REM choose new location if snake body is there 990 PEN 3:PRINT n;: LET flag=0 : REM display new random number if needed 999 GOTO 300 : REM back to start of game loop 1000 REM GAME OVER 1010 PEN 4 : REM use flashing ink 1020 LOCATE 2,10 : REM centre message on screen 1030 PRINT "G A M E O V E R";: REM display game over message 1040 LET i$=inkey$ : REM get user input 1050 IF i$="" THEN GOTO 1040 : REM keep waiting until user presses a key 1060 PEN 1 : REM use default OS ink colour Final 10 Liner Listing ---------------------- 1 DIM p(500,2):t=1:h=1:x=10:y=10:s=-10:m=750:d$="z":f=1:MODE 0:INK 2,26:INK 3,6:INK 4,6,26 2 p(h,1)=x:p(h,2)=y:h=h+1:LOCATE x,y:PEN 1:?"*";:s=s+10:PEN 2:LOCATE 12,1:? s;:FOR z=1 TO m:NEXT:IF h>500 THEN h=1 3 IF g<>0 THEN g=g-1 ELSE LOCATE p(t,1),p(t,2):?" ";: t=t+1:IF t>500 THEN t=1 4 i$=INKEY$:IF i$<>"" THEN d$=i$ 5 IF d$="z" THEN x=x-1 ELSE IF d$="x" THEN x=x+1 ELSE IF d$="p" THEN y=y-1 ELSE IF d$="l" THEN y=y+1 6 IF x<1 OR x>20 OR y<2 OR y>25 THEN GOTO 10 7 LOCATE x,y:c$=COPYCHR$(#0):IF c$="*" THEN GOTO 10 ELSE IF c$<>" " THEN g=g+n:s=s+n:m=m-n:f=1 8 IF f=0 THEN GOTO 2 ELSE n=INT((RND(1)*9)+1):v=INT((RND(1)*20)+1):w=INT((RND(1)*25)+1):IF w=1 THEN GOTO 8 9 LOCATE v,w:c$=COPYCHR$(#0):IF c$="*" THEN GOTO 8 ELSE PEN 3:? n;:f=0:GOTO 2 10 PEN 4:LOCATE 2,10:?"G A M E O V E R";:i$=inkey$:IF i$="" THEN GOTO 10 ELSE PEN 1