scale_polygon Module Reference

module common / Polygon More...

Functions/Subroutines
logical function, public	polygon_inpoly (pt_x, pt_y, num_node, v_x, v_y)
	Check whether the point is located inside a polyngon.

Detailed Description

module common / Polygon

Description

A module to provide utilities for polygon

Reference

Author

Yuta Kawai, Team SCALE

Function/Subroutine Documentation

polygon_inpoly()

logical function, public scale_polygon::polygon_inpoly	(	real(rp), intent(in)	pt_x,
		real(rp), intent(in)	pt_y,
		integer, intent(in)	num_node,
		real(rp), dimension(num_node), intent(in)	v_x,
		real(rp), dimension(num_node), intent(in)	v_y )

Check whether the point is located inside a polyngon.

Definition at line 32 of file scale_polygon.F90.

    implicit none
    real(RP), intent(in) :: pt_x
    real(RP), intent(in) :: pt_y
    integer, intent(in) :: num_node
    real(RP), intent(in) :: v_x(num_node)
    real(RP), intent(in) :: v_y(num_node)
    logical :: ret
 
    integer :: wn
    integer :: i, ii
    !------------------------------------------
 
    wn = 0
    do i=1, num_node
      ii = mod(i, num_node) + 1
      if ( v_y(i) <= pt_y .and. pt_y < v_y(ii)) then
        if( pt_x < v_x(i) + (pt_y - v_y(i)) * (v_x(ii) - v_x(i))/(v_y(ii) - v_y(i)) ) then
          wn = wn + 1
        end if
      else if ( v_y(i) > pt_y .and. v_y(ii) <= pt_y ) then
        if( pt_x < v_x(i) + (pt_y - v_y(i)) * (v_x(ii) - v_x(i))/(v_y(ii) - v_y(i)) ) then
          wn = wn - 1
        end if
      end if
    end do
 
    if (wn == 0) then
      ret = .false.
    else
      ret = .true.
    end if
 
    return