( M A P )
: +pos ( x1 y1 x2 y2 -- x y )
  <rot + >rot + swap ;

var tileselect
: invalidate-map mapsize mapsize! ;
: mouseworldpos mousepos scrollpos +pos ;
: mousetile mouseworldpos world>tile ;
: tile ( x y -- ptr ) mapsize drop * + map + ;

1 const WALKABLE
2 const DRIVABLE

array tileflags
( grass )      WALKABLE b,
( dirt )       WALKABLE DRIVABLE | b,
( water )      0 b,
( pavement )   WALKABLE DRIVABLE | b,
( brick )      0 b,
( forest )     0 b,
( roof )       0 b,
( brick )      0 b,
( window )     0 b,
( carpet )     WALKABLE b,
( wallpaper )  0 b,
( tile )       WALKABLE b,
( door )       0 b,
( cabinet )    0 b,
( fridge )     0 b,
( countertop ) 0 b,
( sink )       0 b,
( house )      0 b,
( fence )      0 b,
( storefront ) 0 b,

here tileflags - 1 - const MAXTILE

: mapflag? ( x y flag -- b ) >rot tile b@ tileflags + b@ & ;
: walkable? ( x y -- b ) WALKABLE mapflag? ;
: drivable? ( x y -- b ) DRIVABLE mapflag? ;

: tick-mapedit
  tileselect @
  ^< key-pressed if 1 - then
  ^> key-pressed if 1 + then
  dup 0 < if drop MAXTILE then
  dup MAXTILE > if drop 0 then
  tileselect !

  MOUSEL mousedown if tileselect @ mousetile tile b! invalidate-map then
  MOUSER clicked if
    mouseworldpos world>tile
    2dup tile b@ tileselect !
    swap . . cr then ;

: copy-mapseg ( neww oldw y -- )
  >r ( oldw neww r: y )
  2dup min >rot ( copyw neww oldw )
  r@ * map + ( copyw neww src )
  swap <r * map + ( copyw src dst )
  swap <rot memmove ;

: resize-map ( neww newh -- )
  swap mapsize >r ( newh neww oldw r: oldh )
  2dup < if 1 <r else <r 1 - 0 then ( newh neww copyw ystart ylim )
  for 2dup i copy-mapseg next
  drop swap mapsize! ;

: mapw mapsize drop ;
: maph mapsize nip ;

: offset-map ( p d -- p ) dup 0 < if drop else + then ;

: shift-map ( dx dy -- )
  maph over abs - >r ( dx dy r: h )
  swap mapw over abs - >rot ( w dy dx r: h )
  2dup map swap offset-map
    swap mapw * offset-map >rot ( w end dy dx r: h )
  map swap negate offset-map
    swap mapw * negate offset-map ( w end start r: h )
  2dup > if r@ mapw * + swap r@ mapw * + swap then
  <r 0 for
    3dup <rot memmove
    2dup < if mapw + swap mapw + swap
	   else mapw - swap mapw - swap then
  next drop drop drop invalidate-map ;

: save-map ( filename -- )
  fdeactivate swap overwrite
  mapsize swap fput fput
  mapsize * map fwrite
  factivate ;

: load-map ( filename -- )
  fdeactivate swap open
  fget fget
  2dup * map fread
  mapsize!
  factivate ;

: fill-map ( tile -- )
  0 mapsize * for dup map i + b! next drop invalidate-map ;