Continuous Visible Query for Three-Dimensional Objects in Spatial Databases

Algorithm 1

Visible range query.

Input: ObjectSet ; QueryPoint ; Range

Output: ResultSet

(1) Object = RangeQuery(, , ); //do the range query,

(2) Sorting();

(3) for  (every element in )  do

(4)  if  Boolean(, obstructSet(, ))  then

(5)   Add , , into ;

(6)   Add into ;

(7)  else

(8)   Boolean(, obstructSet(, ))

(9)   if   visible  then

(10)    Add into ;

(11)     Add , , into ;

(12)    end if

(13)   end if

(14) end for

(15) Return ;