itemscatter.j

library itemscatter initializer init
    globals
        // config
        private real RADIUS = 32.00
        private real PERIOD = 1.00 / 64.00
        // internal
        private item current = null
    endglobals

    private function Abs takes real r returns real
        if (r < 0.00) then
            return -r
        endif
        return r
    endfunction

    private function filter takes nothing returns boolean
        return true
    endfunction

    private function callbackB takes nothing returns nothing
     local real sr = RADIUS
     local real cx
     local real cy
     local real ox
     local real oy
     local real dx
     local real dy
     local real a
     local real mx
     local real my
     local item other = GetEnumItem()

        if (current == other) then
            return
        endif

        set cx = GetItemX(current)
        set cy = GetItemY(current)
        set ox = GetItemX(other)
        set oy = GetItemY(other)
        set dx = cx - ox
        set dy = cy - oy

        if (Abs(dx) < 0.01) then
            set dx = GetRandomReal(-0.10, 0.10)
        endif

        if (Abs(dy) < 0.01) then
            set dy = GetRandomReal(-0.10, 0.10)
        endif 
        
        if (dx * dx + dy * dy < sr * sr) then // we're too close
            set mx = 0.50 * (cx + ox)
            set my = 0.50 * (cy + oy)
            set a = Atan2(dy, dx)
            set cx = mx - Cos(a) * RADIUS
            set cy = my - Sin(a) * RADIUS
            set ox = mx + Cos(a) * RADIUS
            set oy = my + Sin(a) * RADIUS
            call SetItemPosition(current, cx, cy)
            call SetItemPosition(other, ox, oy)
        endif

     set other = null
    endfunction

    private function callbackA takes nothing returns nothing
        set current = GetEnumItem()
        call EnumItemsInRect(GetWorldBounds(), function filter, function callbackB)
    endfunction

    private function action takes nothing returns nothing
        call EnumItemsInRect(GetWorldBounds(), function filter, function callbackA)
    endfunction

    // remove this
    private function test takes nothing returns nothing
     local integer i = 0
        loop
            call CreateItem('afac', 0.00, -3328.00)

            set i = i + 1
            exitwhen i == 16
        endloop
    endfunction

    private function init takes nothing returns nothing
     local trigger t = CreateTrigger()
        call TriggerAddAction(t, function action)
        call TriggerRegisterTimerEvent(t, PERIOD, true)

        call test()
    endfunction
endlibrary