duvenhage-top-loop-activity-diagram.puml

' Copyright 2013-2022 CS GROUP
' Licensed to CS GROUP (CS) under one or more
' contributor license agreements.  See the NOTICE file distributed with
' this work for additional information regarding copyright ownership.
' CS licenses this file to You under the Apache License, Version 2.0
' (the "License"); you may not use this file except in compliance with
' the License.  You may obtain a copy of the License at
'
'   http://www.apache.org/licenses/LICENSE-2.0
'
' Unless required by applicable law or agreed to in writing, software
' distributed under the License is distributed on an "AS IS" BASIS,
' WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
' See the License for the specific language governing permissions and
' limitations under the License.

@startuml

  skinparam svek                                true
  skinparam NoteBackgroundColor                 #F3EFEB
  skinparam NoteBorderColor                     #691616
  skinparam NoteFontColor                       #691616
  skinparam ActivityStartColor                  #6A584B
  skinparam ActivityEndColor                    #6A584B
  skinparam ActivityBarColor                    #6A584B
  skinparam ActivityBorderColor                 #691616
  skinparam ActivityBackgroundColor             #F3EFEB/CCC9C5
  skinparam ActivityArrowColor                  #691616
  skinparam ActivityFontSize                    11

  start
  : gp₀ ⇦ point at altitude 0;
  : select tile containing gp₀;
  : current point ⇦ null;
  : hmax ⇦ tile maximum elevation;
  while (current point is null)
    : current ⇦ point at altitude hmax;
    if (locate current point) then (in selected tile)
    else (outside of selected tile)
      : select tile containing current point;
      : hmax ⇦ max(hmax, tile maximum elevation);
      : current point ⇦ null;
    endif
  endwhile
  repeat
    : exit ⇦ line-of-sight exit point from tile;
    : intersection ⇦ Duvenhage(current, exit);
    if (intersection found?) then (yes)
      : return intersection;
      stop
    endif
    if (tile exit) then (bottom)
      : searching ⇦ false;
    else (side)
      : forward point ⇦ point slightly after exit point;
      : select tile containing forward point;
      if (DEM traversed between\ncurrent and forward points?) then (yes)
        : return current point;
        note right
         extremely rare case!
        end note
        stop
      endif
      : current point ⇦ forward point;
    endif
  repeat while (searching ?)
  :search failed;
  note left
    this should never happen
  end note

@enduml