Maze generation: Difference between revisions

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In order to preserve the aspect ratio (for most display terminals), several   '''changestr'''   invocations and
In order to preserve the aspect ratio (for most display terminals), several   '''changestr'''   invocations and
<br>some other instructions were added to increase the horizontal dimension (cell size).
<br>some other instructions were added to increase the horizontal dimension (cell size).
<lang rexx>/*REXX program generates and displays a rectangular solvable maze (any size).*/
<lang rexx>/*REXX program generates and displays a rectangular solvable maze (of any size).*/
height=0; @.=0 /*default for all cells visited. */
height=0; @.=0 /*default for all cells visited. */
parse arg rows cols seed . /*allow user to specify the maze size. */
parse arg rows cols seed . /*allow user to specify the maze size. */
if rows='' | rows==',' then rows=19 /*No rows given? Then use the default.*/
if rows='' | rows=="," then rows=19 /*No rows given? Then use the default.*/
if cols='' | cols==',' then cols=19 /* " cols " ? " " " " */
if cols='' | cols=="," then cols=19 /* " cols " ? " " " " */
if seed\=='' then call random ,,seed /*use a random seed for repeatability.*/
if seed\=='' then call random ,,seed /*use a random seed for repeatability.*/
call buildRow '┌'copies('~┬',cols-1)'~┐' /*construct top edge of the maze. */
call buildRow '┌'copies("~┬",cols-1)'~┐' /*construct the top edge of the maze. */
/* [↓] construct the maze's grid. */
/* [↓] construct the maze's grid. */
do r=1 for rows; _=; __=; hp= '|'; hj='├'
do r=1 for rows; _=; __=; hp= "|"; hj='├'
do c=1 for cols; _= _||hp'1'; __=__||hj'~'; hj='┼'; hp=''
do c=1 for cols; _= _||hp'1'; __=__||hj"~"; hj='┼'; hp=""
end /*c*/
end /*c*/
call buildRow _'│' /*construct the right edge of cells.*/
call buildRow _'│' /*construct the right edge of the cells*/
if r\==rows then call buildRow __'┤' /* " " " " " maze. */
if r\==rows then call buildRow __'┤' /* " " " " " " maze.*/
end /*r*/
end /*r*/


call buildRow '└'copies('~┴',cols-1)'~┘' /*construct the bottom maze edge.*/
call buildRow '└'copies("~┴", cols-1)'~┘' /*construct the bottom edge of the maze*/
r!=random(1,rows)*2; c!=random(1,cols)*2; @.r!.c!=0 /*choose the 1st cell.*/
r!=random(1,rows)*2; c!=random(1,cols)*2; @.r!.c!=0 /*choose the first cell in maze*/
/* [↓] traipse through the maze. */
/* [↓] traipse through the maze. */
do forever; n=hood(r!,c!); if n==0 then if \fCell() then leave
do forever; n=hood(r!,c!)
if n==0 then if \fCell() then leave
call ?; @._r._c=0 /*get the (next) maze direction to go. */
ro=r!; co=c!; r!=_r; c!=_c /*save original maze cell coordinates. */
call ?; @._r._c=0 /*get the (next) maze direction to go. */
?.zr=?.zr%2; ?.zc=?.zc%2 /*get the maze row and cell directions.*/
ro=r!; co=c!; r!=_r; c!=_c /*save original maze cell coordinates. */
rw=ro+?.zr; cw=co+?.zc /*calculate the next row and column. */
?.zr=?.zr%2; ?.zc=?.zc%2 /*get the maze row and cell directions.*/
@.rw.cw=. /*mark the maze cell as being visited. */
rw=ro+?.zr; cw=co+?.zc /*calculate the next row and column. */
@.rw.cw=. /*mark the maze cell as being visited. */
end /*forever*/
end /*forever*/


do r=1 for height; _= /*display the maze. */
do r=1 for height; _= /*display the maze. */
do c=1 for cols*2 + 1; _=_ || @.r.c; end /*c*/
do c=1 for cols*2 + 1; _=_ || @.r.c; end /*c*/
if \(r//2) then _=translate(_, '\', .) /*trans to backslash*/
if \(r//2) then _=translate(_, '\', .) /*trans to backslash*/
@.r=_ /*save the row in @.*/
@.r=_ /*save the row in @.*/
end /*r*/
end /*r*/


do #=1 for height; _=@.# /*display maze to the terminal. */
do #=1 for height; _=@.# /*display the maze to the terminal. */
call makeNice /*make some cell corners prettier*/
call makeNice /*make some cell corners look prettier.*/


_=changestr(1,_,111) /*──────these four ────────────────────*/
_=changestr(1 , _, 111) /*──────these four ────────────────────*/
_=changestr(0,_,000) /*───────── statements are ────────────*/
_=changestr(0 , _, 000) /*───────── statements are ────────────*/
_=changestr( . ,_," ") /*────────────── used for preserving ──*/
_=changestr(. , _, " ") /*────────────── used for preserving ──*/
_=changestr('~',_,"───") /*────────────────── the aspect ratio. */
_=changestr('~' , _, "───") /*────────────────── the aspect ratio. */
say translate(_, '─│', "═|\10") /*make it presentable for the screen. */
say translate(_ , '─│', "═|\10") /*make it presentable for the screen. */
end /*#*/
end /*#*/
exit /*stick a fork in it, we're all done. */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*────────────────────────────────────────────────────────────────────────────*/
@: parse arg _r,_c; return @._r._c /*a fast way to reference a maze cell. */
@: parse arg _r,_c; return @._r._c /*a fast way to reference a maze cell. */
hood: parse arg rh,ch; return @(rh+2,ch) + @(rh-2,ch) + @(rh,ch-2) + @(rh,ch+2)
/*────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
?: do forever; ?.=0; ?=random(1,4); if ?==1 then ?.zc=-2 /*north*/
if ?==2 then ?.zr= 2 /* east*/
?: do forever; ?.=0; ?=random(1,4); if ?==1 then ?.zc=-2 /*north*/
if ?==3 then ?.zc= 2 /*south*/
if ?==2 then ?.zr= 2 /* east*/
if ?==4 then ?.zr=-2 /* west*/
if ?==3 then ?.zc= 2 /*south*/
_r=r!+?.zr; _c=c!+?.zc; if @._r._c==1 then return
if ?==4 then ?.zr=-2 /* west*/
_r=r!+?.zr; _c=c!+?.zc; if @._r._c==1 then return
end /*forever*/
end /*forever*/
/*────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
buildRow: parse arg z; height=height+1; width=length(z)
buildRow: parse arg z; height=height+1; width=length(z)
do c=1 for width; @.height.c=substr(z,c,1); end; return
do c=1 for width; @.height.c=substr(z,c,1); end; return
/*────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
fCell: do r=1 for rows; rr=r+r
do c=1 for cols; cc=c+c
fCell: do r=1 for rows; rr=r+r
if hood(rr,cc)==1 then do; r!=rr; c!=cc; @.r!.c!=0; return 1; end
do c=1 for cols; cc=c+c
if hood(rr, cc)==1 then do; r!=rr; c!=cc; @.r!.c!=0; return 1; end
end /*c*/
end /*r*/ /* [↑] r! & c! are used by invoker.*/
end /*c*/
end /*r*/ /* [↑] r! and c! are used by invoker.*/
return 0
return 0
/*────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
hood: parse arg rh,ch; return @(rh+2,ch) + @(rh-2,ch) + @(rh,ch-2) + @(rh,ch+2)
makeNice: width=length(_); old=#-1; new=#+1; old_=@.old; new_=@.new
/*────────────────────────────────────────────────────────────────────────────*/
if left(_,2) =='.' then _=translate(_, "|", '├')
makeNice: width=length(_); old=#-1; new=#+1; old_=@.old; new_=@.new
if left(_,2) =='.' then _=translate(_, '|', "├")
if right(_,2)=='.' then _=translate(_, "|", '┤')
/* [↓] handle the top row of the grid.*/
if right(_,2)=='.' then _=translate(_, '|', "┤")
/* [↓] handle the top grid row.*/
do k=1 for width while #==1; z=substr(_,k,1) /*maze top row.*/
do k=1 for width while #==1; z=substr(_,k,1) /*maze top row.*/
if z\=='┬' then iterate
if z\=='┬' then iterate
if substr(new_,k,1)=='\' then _=overlay("═",_,k)
if substr(new_,k,1)=='\' then _=overlay('═',_,k)
end /*k*/
end /*k*/


do k=1 for width while #==height; z=substr(_,k,1) /*maze bot row.*/
do k=1 for width while #==height; z=substr(_,k,1) /*maze bot row.*/
if z\=='┴' then iterate
if z\=='┴' then iterate
if substr(old_,k,1)=='\' then _=overlay('',_,k)
if substr(old_, k, 1)=='\' then _=overlay("", _, k)
end /*k*/
end /*k*/
/* [↓] handle the mid grid rows*/
/* [↓] handle the mid rows of the grid*/
do k=3 to width-2 by 2 while #//2; z=substr(_,k,1) /*maze mid rows*/
do k=3 to width-2 by 2 while #//2; z=substr(_,k,1) /*maze mid rows*/
if z\=='┼' then iterate
if z\=='┼' then iterate
le=substr(_,k-1,1)
le=substr(_,k-1,1)
ri=substr(_,k+1,1)
ri=substr(_,k+1,1)
up=substr(old_,k,1)
up=substr(old_,k,1)
dw=substr(new_,k,1)
dw=substr(new_,k,1)
select
select
when le== . & ri== . & up=='│' & dw=='' then _=overlay('|',_,k)
when le== . & ri== . & up=='│' & dw=="" then _=overlay('|',_,k)
when le=='~' & ri=='~' & up=='\' & dw=='\' then _=overlay('═',_,k)
when le=='~' & ri=="~" & up=='\' & dw=="\" then _=overlay('═',_,k)
when le=='~' & ri=='~' & up=='\' & dw=='' then _=overlay('┬',_,k)
when le=='~' & ri=="~" & up=='\' & dw=="" then _=overlay('┬',_,k)
when le=='~' & ri=='~' & up=='│' & dw=='\' then _=overlay('┴',_,k)
when le=='~' & ri=="~" & up=='│' & dw=="\" then _=overlay('┴',_,k)
when le=='~' & ri== . & up=='\' & dw=='\' then _=overlay('═',_,k)
when le=='~' & ri== . & up=='\' & dw=="\" then _=overlay('═',_,k)
when le== . & ri=='~' & up=='\' & dw=='\' then _=overlay('═',_,k)
when le== . & ri=="~" & up=='\' & dw=="\" then _=overlay('═',_,k)
when le== . & ri== . & up=='│' & dw=='\' then _=overlay('|',_,k)
when le== . & ri== . & up=='│' & dw=="\" then _=overlay('|',_,k)
when le== . & ri== . & up=='\' & dw=='' then _=overlay('|',_,k)
when le== . & ri== . & up=='\' & dw=="" then _=overlay('|',_,k)
when le== . & ri=='~' & up=='\' & dw=='' then _=overlay('┌',_,k)
when le== . & ri=="~" & up=='\' & dw=="" then _=overlay('┌',_,k)
when le== . & ri=='~' & up=='│' & dw=='\' then _=overlay('└',_,k)
when le== . & ri=="~" & up=='│' & dw=="\" then _=overlay('└',_,k)
when le=='~' & ri== . & up=='\' & dw=='' then _=overlay('┐',_,k)
when le=='~' & ri== . & up=='\' & dw=="" then _=overlay('┐',_,k)
when le=='~' & ri== . & up=='│' & dw=='\' then _=overlay('┘',_,k)
when le=='~' & ri== . & up=='│' & dw=="\" then _=overlay('┘',_,k)
when le=='~' & ri== . & up=='│' & dw=='' then _=overlay('┤',_,k)
when le=='~' & ri== . & up=='│' & dw=="" then _=overlay('┤',_,k)
when le== . & ri=='~' & up=='│' & dw=='' then _=overlay('├',_,k)
when le== . & ri=="~" & up=='│' & dw=="" then _=overlay('├',_,k)
otherwise nop
otherwise nop
end /*select*/
end /*select*/
end /*k*/
end /*k*/
return</lang>
return</lang>
Some older REXXes don't have a &nbsp; '''changestr''' &nbsp; BIF, so one is included here &nbsp; ──► &nbsp; [[CHANGESTR.REX]].
Some older REXXes don't have a &nbsp; '''changestr''' &nbsp; BIF, so one is included here &nbsp; ──► &nbsp; [[CHANGESTR.REX]].
<br><br>
<br><br>