A downloadable game

Instructions:

You are a warehouse worker im a warehouse. You need to push the crates onto their final positions as indicated by the dots.

You can only push crates, not pull them. You can only push one crate at a time. This version has only 1 level.


If you have managed to solve the level then try to do it in the minimum number of moves possible (463).

Keys:

Cursor keys

Copy (note that the Copy key is mapped to the End key in JSBeeb) to restart the level.

Variables used:

m - one less than the number of rows in the level

l - one less than the number in columns in the level

g(m,l) - the level data array

a,b,r - general purpose variables

x,y - x and y coordinates of worker

z - number of moves made

c - number of crates not on dots (the level has been completed and the game ends when this is zero)

k - key pressed

p - set when a move has been made. 8 = moving into a blank space, 3 = pushing a crate, 0 = not a valid move

Level data:

0 - blank space

1 - dot

2 - crate

3 - crate on dot

4 - worker

5 - worker on dot

6 - wall

The level data is stored in the REM on line 100 (line 1000 in the expanded version). As the 7 "building blocks" as listed above only require 3 bits to store them (i.e. 000 to 110), 2 "building blocks" are stored in each character.

Program structure (referring to the expanded version):

lines 100 to 308 initialisation

lines 309 to 803 main game loop

lines 804 to 900 "game over"

lines 901 to 1000 data


Expanded listing with comments:
100l=13
101m=09
102DIMg(m,l)
define the graphics characters
103FORa=&C00TO&C37
104?a=(a?&F17-32)*3
105NEXT
read/decode the level data and display the level
106a=&1B54
107b=0
disable cursor keys for editing
108*FX4,1
200MODE4
disable cursor
201VDU23,1,0;0;0;0;
initialise move count
202z=0
initialise crate not on dot count
203c=10
204FORj=0TOm
205FORi=0TOl
206g(j,i)=(?a-32)DIV8^b MOD8
300VDU224+g(j,i)
301a=a+b
302b=1-b
303NEXT
304PRINT
305NEXT
display the number of moves made (0)
306PRINT;0
set the x and y coordinates of worker
307x=07
308y=04
309REPEAT
310k=GET-135
if key press was invalid then try again
400IFk<0ORk>4THENUNTIL0
401r=ASC(MID$("DCEGA",k+1,1))-64
402b=r DIV3-1
403a=r MOD3-1
look at what lies in the direction that we are going
500r=g(y+b,x+a)AND6
501p=0
if it's a blank space/dot or a crate with a blank space/dot on the other side of it then it's a valid move
502IFr=0THENp=8ELSEIFr=2THENIF(g(y+b*2,x+a*2)AND6)=0THENp=3
if not a valid move then try again unless Copy key was pressed in which case restart level
600IFp=0THENUNTILk=0:RUN
valid move so increment move count
601z=z+1
make move
move worker off current position
602g(y,x)=g(y,x)AND1
603x=x+a
604y=y+b
increment c if crate was pushed off a dot
605c=c-(g(y,x)=p)
move worker to new position
700g(y,x)=g(y,x)AND1OR4
also move crate to new position if pushing one
701g(y+b,x+a)=g(y+b,x+a)ORr
decrement c if crate was pushed onto a dot
702c=c+(g(y+b,x+a)=p)
redisplay "local" blocks affected by move
703FORr=-1TO1
800VDU31,x+a*r,y+b*r,224+g(y+b*r,x+a*r)
801NEXT
display the number of moves made
802PRINTTAB(0,m+1);z
803UNTILc=0
enable cursor keys for editing
804*FX4,0
enable cursor
900VDU23,1,1;0;0;0;
graphics data
901REM           ((   uKSWWSKuuKS__SKu4JiuuaJ44JiuuaJ4mmm JJJ 
level data
1000REMVVVVVV .!P  PV.!P0 "P.!PRV&P.! @P&P.!PP "VVVVP60P &"000P & P  P VVVVVV

Install instructions

The emulator that I use is an online one - JSBeeb. https://bbc.godbolt.org/

Simply copy and paste the program into it and type RUN.

The program assumes that PAGE (the start of the program) is set to &1900 which is the default in JSBeeb.

Download

Download
SOKOBAN.txt 925 bytes
Download
SOKOBAN80.txt 798 bytes
Download
Sokoban (instructions).txt 3 kB

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