mesecons_x/mesecons_autotools/book/misc.lua

function rotate_node_to_direction(node,direction)
        local add = 0 
        if direction.x == 1 then add = 3 end
        if direction.x == -1 then add = 1 end
        if direction.z == 1 then add = 0 end
        if direction.z == -1 then add = 2 end
        
        local param2 = node.param2 
        
        param2 = (param2+add)% 4
        
        return { name = node.name , param2 = param2 } 
end

local function direction_to_number(direction)
        if( direction.z == 1 ) then
                return 1
        elseif( direction.x == 1 ) then
                return 2
        elseif(direction.z == -1 )then
                return 3
        else
                return 4
        end
        
end



function rotate_node(node, saved_direction,direction)       
        
        local values = 
        {
                {0,1,2,3},
                {3,0,1,2},
                {2,3,0,1},
                {1,2,3,0}
        }
        
       local rotate = 
               values[direction_to_number(saved_direction)][direction_to_number(direction)]
         
        local new_node = {}
        new_node.name = node.name
        new_node.param2 = (node.param2+rotate)%4
        
        return new_node
end