다각형의 중립축에서의 폭 계산

다각형의 중립축에서의 폭 계산

1. 중립축 x와 다각형의 교차점을 찾는다.
2. 교차점의 x좌표값이 작은 순서대로 오름차순으로 정렬한다.
3. 폭 B를 계산한다.
B = 짝수번째 x좌표값의 합 - 홀수번째 x좌표값의 합

다각형의 중립축에서의 폭 계산.pdf

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드디어 교차되는 폭을 계산하는 코드를 완성했다.
물론 인터넷에서 도움을 받았다.

Public Function calc_width(x1 As Double, y1 As Double, x2 As Double, y2 As Double, Polygon As Variant) As Variant
    Dim x As Long, m As Double, b As Double, Poly As Variant
    Dim LB1 As Long, LB2 As Long, UB1 As Long, UB2 As Long, NumSidesCrossed As Long
    
    Dim dblCrossX As Double
    Dim dblCrossY As Double
    Dim dblTestx1 As Double
    Dim dblTesty1 As Double
    Dim dblTestx2 As Double
    Dim dblTesty2 As Double
    Dim arrCrossX() As Variant
    Dim z As Integer
    Dim vaArr_Sort As Variant
    Dim oddx As Double
    Dim evenx As Double
    
    
    Poly = Polygon
    
    For x = LBound(Poly) To UBound(Poly) - 1
        dblTestx1 = Poly(x, 1)
        dblTesty1 = Poly(x, 2)
        dblTestx2 = Poly(x + 1, 1)
        dblTesty2 = Poly(x + 1, 2)
       
        If m_CalculateIntersection(x1, y1, x2, y2, dblTestx1, dblTesty1, dblTestx2, dblTesty2, dblCrossX, dblCrossY) Then
                z = z + 1
                ReDim Preserve arrCrossX(1 To z)
                arrCrossX(z) = dblCrossX
        End If
    Next
    
   vaArr_Sort = SortArray(arrCrossX, xlAscending, True)
    
    For x = 1 To UBound(vaArr_Sort)
        If CBool(x Mod 2) Then
            oddx = oddx + vaArr_Sort(x)
        Else
            evenx = evenx + vaArr_Sort(x)
        End If
    Next
    
    calc_width = evenx - oddx

End Function

m_CalculateIntersection, SortArray는 인터넷에서 구한 함수이다.