on construct me 
  return TRUE
end

on deconstruct me 
  return TRUE
end

on testForLineOfSight me, tLineOfSightTester, tX1, tY1, tX2, tY2, tBlockingLevel, tExcludeFirst, tExcludeLast 
  tDeltaX = (tX2 - tX1)
  tDeltaY = (tY2 - tY1)
  tDump = 0
  if tDump then
    put("* X1/Y1:" && tX1 && tY1 && "X2/Y2:" && tX2 && tY2 && "* tDeltaX" && tDeltaX && "* tDeltaY" && tDeltaY)
  end if
  if (tDeltaX = 0) then
    if tDump then
      put("* 1")
    end if
    if (tDeltaY = 0) then
      if tExcludeFirst or tExcludeLast then
        return TRUE
      end if
      return(tLineOfSightTester.isBlockingLineOfSight(tX1, tY1, tBlockingLevel))
    end if
    if tDeltaY > 0 then
      if tDump then
        put("* 1b")
      end if
      tYFirst = tY1
      if tExcludeLast then
        tYLast = (tY2 - 1)
      else
        tYLast = tY2
      end if
      tY = tYFirst
      repeat while tY <= tYLast
        if tExcludeFirst then
          tExcludeFirst = 0
        else
          if tLineOfSightTester.isBlockingLineOfSight(tX1, tY, tBlockingLevel) then
            return FALSE
          end if
        end if
        tY = (1 + tY)
      end repeat
      exit repeat
    end if
    if tDump then
      put("* 1c")
    end if
    tYFirst = tY1
    if tExcludeLast then
      tYLast = (tY2 + 1)
    else
      tYLast = tY2
    end if
    tY = tYFirst
    repeat while tY >= tYLast
      if tExcludeFirst then
        tExcludeFirst = 0
      else
        if tLineOfSightTester.isBlockingLineOfSight(tX1, tY, tBlockingLevel) then
          return FALSE
        end if
      end if
      tY = (255 + tY)
    end repeat
    exit repeat
  end if
  if (tDeltaY = 0) then
    if tDump then
      put("* 2")
    end if
    if tDeltaX > 0 then
      if tDump then
        put("* 2a")
      end if
      tXFirst = tX1
      if tExcludeLast then
        tXLast = (tX2 - 1)
      else
        tXLast = tX2
      end if
      tX = tXFirst
      repeat while tX <= tXLast
        if tExcludeFirst then
          tExcludeFirst = 0
        else
          if tLineOfSightTester.isBlockingLineOfSight(tX, tY1, tBlockingLevel) then
            return FALSE
          end if
        end if
        tX = (1 + tX)
      end repeat
      exit repeat
    end if
    if tDump then
      put("* 2b")
    end if
    tXFirst = tX1
    if tExcludeLast then
      tXLast = (tX2 + 1)
    else
      tXLast = tX2
    end if
    tX = tXFirst
    repeat while tX >= tXLast
      if tExcludeFirst then
        tExcludeFirst = 0
      else
        if tDump then
          put("* isBlockingLineOfSight result" && tX && tY1 && tLineOfSightTester.isBlockingLineOfSight(tX, tY1, tBlockingLevel))
        end if
        if tLineOfSightTester.isBlockingLineOfSight(tX, tY1, tBlockingLevel) then
          return FALSE
        end if
      end if
      tX = (255 + tX)
    end repeat
    exit repeat
  end if
  if tDeltaX > 0 then
    if tDump then
      put("* 3")
    end if
    if tDeltaY > 0 then
      if tDeltaX > tDeltaY then
        if tDump then
          put("* 3a")
        end if
        tY = tY1
        tD = ((tDeltaY * 4) - tDeltaX)
        tXFirst = tX1
        if tExcludeLast then
          tXLast = (tX2 - 1)
        else
          tXLast = tX2
        end if
        tX = tXFirst
        repeat while tX <= tXLast
          if tExcludeFirst then
            tExcludeFirst = 0
          else
            if tLineOfSightTester.isBlockingLineOfSight(tX, tY, tBlockingLevel) then
              return FALSE
            end if
          end if
          if tD < 0 then
            tD = (tD + (tDeltaY * 4))
          else
            tD = (tD + ((tDeltaY - tDeltaX) * 4))
            tY = (tY + 1)
          end if
          tX = (1 + tX)
        end repeat
        exit repeat
      end if
      if tDump then
        put("* 3b")
      end if
      tX = tX1
      tD = ((tDeltaX * 4) - tDeltaY)
      tYFirst = tY1
      if tExcludeLast then
        tYLast = (tY2 - 1)
      else
        tYLast = tY2
      end if
      tY = tYFirst
      repeat while tY <= tYLast
        if tExcludeFirst then
          tExcludeFirst = 0
        else
          if tDump then
            put("* testing" && tX && tY)
          end if
          if tLineOfSightTester.isBlockingLineOfSight(tX, tY, tBlockingLevel) then
            return FALSE
          end if
        end if
        if tD < 0 then
          tD = (tD + (tDeltaX * 4))
        else
          tD = (tD + ((tDeltaX - tDeltaY) * 4))
          tX = (tX + 1)
        end if
        tY = (1 + tY)
      end repeat
      exit repeat
    end if
    tDeltaY = -tDeltaY
    if tDeltaX > tDeltaY then
      if tDump then
        put("* 3c")
      end if
      tY = tY1
      tD = ((tDeltaY * 4) - tDeltaX)
      tXFirst = tX1
      if tExcludeLast then
        tXLast = (tX2 - 1)
      else
        tXLast = tX2
      end if
      tX = tXFirst
      repeat while tX <= tXLast
        if tExcludeFirst then
          tExcludeFirst = 0
        else
          if tLineOfSightTester.isBlockingLineOfSight(tX, tY, tBlockingLevel) then
            return FALSE
          end if
        end if
        if tD < 0 then
          tD = (tD + (tDeltaY * 4))
        else
          tD = (tD + ((tDeltaY - tDeltaX) * 4))
          tY = (tY - 1)
        end if
        tX = (1 + tX)
      end repeat
      exit repeat
    end if
    if tDump then
      put("* 3d")
    end if
    tX = tX1
    tD = ((tDeltaX * 4) - tDeltaY)
    tYFirst = tY1
    if tExcludeLast then
      tYLast = (tY2 + 1)
    else
      tYLast = tY2
    end if
    tY = tYFirst
    repeat while tY >= tYLast
      if tExcludeFirst then
        tExcludeFirst = 0
      else
        if tLineOfSightTester.isBlockingLineOfSight(tX, tY, tBlockingLevel) then
          return FALSE
        end if
      end if
      if tD < 0 then
        tD = (tD + (tDeltaX * 4))
      else
        tD = (tD + ((tDeltaX - tDeltaY) * 4))
        tX = (tX + 1)
      end if
      tY = (255 + tY)
    end repeat
    exit repeat
  end if
  if tDump then
    put("* 4")
  end if
  tDeltaX = -tDeltaX
  if tDeltaY > 0 then
    if tDeltaX > tDeltaY then
      if tDump then
        put("* 4a")
      end if
      tY = tY1
      tD = ((tDeltaY * 4) - tDeltaX)
      tXFirst = tX1
      if tExcludeLast then
        tXLast = (tX2 + 1)
      else
        tXLast = tX2
      end if
      tX = tXFirst
      repeat while tX >= tXLast
        if tExcludeFirst then
          tExcludeFirst = 0
        else
          if tLineOfSightTester.isBlockingLineOfSight(tX, tY, tBlockingLevel) then
            return FALSE
          end if
        end if
        if tD < 0 then
          tD = (tD + (tDeltaY * 4))
        else
          tD = (tD + ((tDeltaY - tDeltaX) * 4))
          tY = (tY + 1)
        end if
        tX = (255 + tX)
      end repeat
      exit repeat
    end if
    if tDump then
      put("* 4b")
    end if
    tX = tX1
    tD = ((tDeltaX * 4) - tDeltaY)
    tYFirst = tY1
    if tExcludeLast then
      tYLast = (tY2 - 1)
    else
      tYLast = tY2
    end if
    tY = tYFirst
    repeat while tY <= tYLast
      if tExcludeFirst then
        tExcludeFirst = 0
      else
        if tLineOfSightTester.isBlockingLineOfSight(tX, tY, tBlockingLevel) then
          return FALSE
        end if
      end if
      if tD < 0 then
        tD = (tD + (tDeltaX * 4))
      else
        tD = (tD + ((tDeltaX - tDeltaY) * 4))
        tX = (tX - 1)
      end if
      tY = (1 + tY)
    end repeat
    exit repeat
  end if
  tDeltaY = -tDeltaY
  if tDeltaX > tDeltaY then
    if tDump then
      put("* 4c")
    end if
    tY = tY1
    tD = ((tDeltaY * 4) - tDeltaX)
    tXFirst = tX1
    if tExcludeLast then
      tXLast = (tX2 + 1)
    else
      tXLast = tX2
    end if
    if tDump then
      put("* tXFirst:" && tXFirst && "tXLast:" && tXLast)
    end if
    tX = tXFirst
    repeat while tX >= tXLast
      if tExcludeFirst then
        tExcludeFirst = 0
      else
        if tLineOfSightTester.isBlockingLineOfSight(tX, tY, tBlockingLevel) then
          return FALSE
        end if
      end if
      if tD < 0 then
        tD = (tD + (tDeltaY * 4))
      else
        tD = (tD + ((tDeltaY - tDeltaX) * 4))
        tY = (tY - 1)
      end if
      tX = (255 + tX)
    end repeat
    exit repeat
  end if
  if tDump then
    put("* 4d")
  end if
  tX = tX1
  tD = ((tDeltaX * 4) - tDeltaY)
  tYFirst = tY1
  if tExcludeLast then
    tYLast = (tY2 + 1)
  else
    tYLast = tY2
  end if
  tY = tYFirst
  repeat while tY >= tYLast
    if tExcludeFirst then
      tExcludeFirst = 0
    else
      if tLineOfSightTester.isBlockingLineOfSight(tX, tY, tBlockingLevel) then
        return FALSE
      end if
    end if
    if tD < 0 then
      tD = (tD + (tDeltaY * 4))
    else
      tD = (tD + ((tDeltaX - tDeltaY) * 4))
      tX = (tX - 1)
    end if
    tY = (255 + tY)
  end repeat
  return TRUE
end