IsTerrainWalkable

//Thanks to anitarf and Vexorian @ wc3c.net for this library, it makes things easier.

library IsTerrainWalkable initializer Init
    globals
        // this value is how far from a point the item may end up for the point to be considered pathable
        private constant real MAX_RANGE=10.
        // the following two variables are set to the position of the item after each pathing check
        // that way, if a point isn't pathable, these will be the coordinates of the nearest point that is
        public real X=0.
        public real Y=0.
        private rect r
        private item check
        private item array hidden
        private integer hiddenMax=0
    endglobals

    private function Init takes nothing returns nothing
        set check=CreateItem('ciri',0,0)
        call SetItemVisible(check,false)
        set r=Rect(0.0,0.0,128.0,128.0)
    endfunction

    private function HideBothersomeItem takes nothing returns nothing
        if IsItemVisible(GetEnumItem()) then
            set hidden[hiddenMax]=GetEnumItem()
            call SetItemVisible(hidden[hiddenMax],false)
            set hiddenMax=hiddenMax+1
        endif
    endfunction

    function IsTerrainWalkable takes real x, real y returns boolean
        // first, hide any items in the area so they don't get in the way of our item
        call MoveRectTo(r,x,y)
        call EnumItemsInRect(r,null,function HideBothersomeItem)
        // try to move the check item and get it's coordinates
        call SetItemPosition(check,x,y)//this unhides the item...
        set X=GetItemX(check)
        set Y=GetItemY(check)
        call SetItemVisible(check,false)//...so we must hide it again
        // before returning, unhide any items that got hidden at the start
        loop
            exitwhen hiddenMax<=0
            set hiddenMax=hiddenMax-1
            call SetItemVisible(hidden[hiddenMax],true)
            set hidden[hiddenMax]=null
        endloop
        // return pathability status
        return (x-X)*(x-X)+(y-Y)*(y-Y)<MAX_RANGE*MAX_RANGE
    endfunction
endlibrary