@Override
  public void processPolygon(OsmPolygon osmPolygon) throws Osm2xpBusinessException {

    // polygon is null or empty don't process it
    if (osmPolygon.getNodes() != null && !osmPolygon.getNodes().isEmpty()) {
      // polygon MUST be in clockwise order
      osmPolygon.setPolygon(GeomUtils.forceClockwise(osmPolygon.getPolygon()));
      // if we're on a single pass mode
      // here we must check if the polygon is on more than one tile
      // if that's the case , we must split it into several polys
      List<OsmPolygon> polygons = new ArrayList<OsmPolygon>();
      if (GuiOptionsHelper.getOptions().isSinglePass()) {
        polygons.addAll(osmPolygon.splitPolygonAroundTiles());
      }
      // if not on a single pass mode, add this single polygon to the poly
      // list
      else {
        polygons.add(osmPolygon);
      }
      // try to transform those polygons into dsf objects.
      for (OsmPolygon poly : polygons) {
        // look for light rules
        processLightObject(poly);

        // try to generate a 3D object
        if (!process3dObject(poly)) {
          // nothing generated? try to generate a facade building.
          if (!processBuilding(poly)) {
            // nothing generated? try to generate a forest.
            processForest(poly);
          }
        }
      }
    }
  }
  /**
   * Compute the facade index for given osm tags, polygon and height.
   *
   * @param tags
   * @param polygon
   * @param height
   * @return Integer the facade index.
   */
  public Integer computeFacadeIndex(OsmPolygon polygon) {
    Integer result = null;
    // first, do we are on a residential object?
    // yes if there is residential or house tag
    // or if surface of the polygon is under the max surface for a
    // residential house
    // and height is under max residential height
    if ((OsmUtils.isValueinTags("residential", polygon.getTags())
            || OsmUtils.isValueinTags("house", polygon.getTags())
            || polygon.getArea() * 10000000 < ASSERTION_RESIDENTIAL_MAX_AREA)
        && polygon.getHeight() < XplaneOptionsHelper.getOptions().getResidentialMax()) {

      result = computeResidentialFacadeIndex(polygon);
    }

    // do we are on a building object?
    // yes if there is industrial or Commercial tag
    // or if surface of the polygon is above the max surface for a
    // residential house
    // and height is above max residential height
    else {
      if (OsmUtils.isValueinTags("industrial", polygon.getTags())
          || OsmUtils.isValueinTags("Commercial", polygon.getTags())
          || polygon.getArea() * 10000000 > ASSERTION_RESIDENTIAL_MAX_AREA
          || polygon.getHeight() > XplaneOptionsHelper.getOptions().getResidentialMax()) {

        result = computeBuildingFacadeIndex(polygon);
      }
    }
    return result;
  }
 /**
  * send a streetLight in the dsf file.
  *
  * @param osmPolygon osm polygon
  * @return true if a streetlight has been written in the dsf file.
  */
 private boolean processStreetLights(OsmPolygon osmPolygon) {
   Boolean result = false;
   if (XplaneOptionsHelper.getOptions().isGenerateStreetLights()
       && OsmUtils.isTagInTagsList("highway", "residential", osmPolygon.getTags())) {
     writeStreetLightToDsf(osmPolygon);
     result = true;
   }
   return result;
 }
  /**
   * write a building in the dsf file.
   *
   * @param polygon
   * @param facade
   * @param size
   */
  private void writeBuildingToDsf(OsmPolygon osmPolygon, Integer facade) {
    if (facade != null && osmPolygon.getHeight() != null) {
      StringBuffer sb = new StringBuffer();
      osmPolygon.setPolygon(GeomUtils.setClockwise(osmPolygon.getPolygon()));
      if (osmPolygon.getPolygon().getArea() * 100000000 > 0.1
          && osmPolygon.getPolygon().getVertexNumber() > 3) {

        sb.append("BEGIN_POLYGON " + facade + " " + osmPolygon.getHeight() + " 2");
        sb.append(System.getProperty("line.separator"));
        sb.append("BEGIN_WINDING");
        sb.append(System.getProperty("line.separator"));

        // on supprime le dernier point pour ne pas boucler
        osmPolygon.getPolygon().removePoint(osmPolygon.getPolygon().getLastPoint());
        for (Point2D loc : osmPolygon.getPolygon().getVertices()) {
          sb.append("POLYGON_POINT " + loc.y + " " + loc.x);
          sb.append(System.getProperty("line.separator"));
        }
        sb.append("END_WINDING");
        sb.append(System.getProperty("line.separator"));
        sb.append("END_POLYGON");
        sb.append(System.getProperty("line.separator"));

        // stats TODO not working anymore since v2 facades new features.
        if (dsfObjectsProvider.getPolygonsList().get(facade).toLowerCase().contains("building")
            || dsfObjectsProvider.getPolygonsList().get(facade).toLowerCase().contains("shape")) {
          StatsHelper.addBuildingType("Building", stats);
        } else {
          if (dsfObjectsProvider.getPolygonsList().get(facade).toLowerCase().contains("house")
              || dsfObjectsProvider
                  .getPolygonsList()
                  .get(facade)
                  .toLowerCase()
                  .contains("common")) {
            StatsHelper.addBuildingType("Residential", stats);
          } else {
            StatsHelper.addBuildingType("Facade rule", stats);
          }
        }
        writer.write(
            sb.toString(), GeomUtils.cleanCoordinatePoint(osmPolygon.getPolygon().getFirstPoint()));
      }
    }
  }
 /**
  * @param way
  * @param polygon
  * @return
  */
 private boolean processForest(OsmPolygon osmPolygon) {
   Boolean result = false;
   if (XplaneOptionsHelper.getOptions().isGenerateFor()) {
     Integer[] forestIndexAndDensity =
         dsfObjectsProvider.getRandomForestIndexAndDensity(osmPolygon.getTags());
     if (forestIndexAndDensity != null) {
       writeForestToDsf(osmPolygon, forestIndexAndDensity);
       result = true;
     }
   }
   return result;
 }
  /**
   * choose and write a 3D object in the dsf file.
   *
   * @param polygon osm polygon.
   * @return true if a 3D object has been written in the dsf file.
   */
  private boolean process3dObject(OsmPolygon osmPolygon) {
    Boolean result = false;

    if (XplaneOptionsHelper.getOptions().isGenerateObj()) {
      // simplify shape if checked and if necessary
      if (GuiOptionsHelper.getOptions().isSimplifyShapes() && !osmPolygon.isSimplePolygon()) {
        osmPolygon.simplifyPolygon();
      }
      XplaneDsfObject object = dsfObjectsProvider.getRandomDsfObject(osmPolygon);
      if (object != null) {
        object.setPolygon(osmPolygon);
        try {
          writeObjectToDsf(object);
          result = true;
        } catch (Osm2xpBusinessException e) {
          result = false;
        }
      }
    }
    return result;
  }
  /**
   * @param polygon the forest polygon
   * @param forestIndexAndDensity index and density of the forest rule
   */
  private void writeForestToDsf(OsmPolygon osmPolygon, Integer[] forestIndexAndDensity) {
    StringBuffer sb = new StringBuffer();
    sb.append("BEGIN_POLYGON " + forestIndexAndDensity[0] + " " + forestIndexAndDensity[1] + " 2");
    sb.append(System.getProperty("line.separator"));
    sb.append("BEGIN_WINDING");
    sb.append(System.getProperty("line.separator"));
    for (Point2D loc : osmPolygon.getPolygon().getVertices()) {
      sb.append("POLYGON_POINT " + loc.y + " " + loc.x);
      sb.append(System.getProperty("line.separator"));
    }
    sb.append("END_WINDING");
    sb.append(System.getProperty("line.separator"));
    sb.append("END_POLYGON");
    sb.append(System.getProperty("line.separator"));

    // stats
    StatsHelper.addForestType(
        dsfObjectsProvider.getPolygonsList().get(forestIndexAndDensity[0]), stats);

    writer.write(
        sb.toString(), GeomUtils.cleanCoordinatePoint(osmPolygon.getPolygon().getFirstPoint()));
  }
  /**
   * compute the dsf index of the residential facade object used for a given polygon
   *
   * @param polygon
   * @param height
   * @return Integer the facade index
   */
  private Integer computeResidentialFacadeIndex(OsmPolygon osmPolygon) {
    Integer result = null;
    // we check if we can use a sloped roof if the user wants them
    if (XplaneOptionsHelper.getOptions().isGenerateSlopedRoofs() && osmPolygon.isSimplePolygon()) {
      result = dsfObjectsProvider.computeFacadeDsfIndex(true, true, true, osmPolygon);
    }
    // no sloped roof, so we'll use a standard house facade
    else {

      // if the polygon is a simple rectangle, we'll use a facade made for
      // simple shaped buildings
      if (osmPolygon.getPolygon().getEdges().size() == 4) {
        result = dsfObjectsProvider.computeFacadeDsfIndex(true, true, false, osmPolygon);
      }
      // the building has a complex footprint, so we'll use a facade made
      // for this case
      else {
        result = dsfObjectsProvider.computeFacadeDsfIndex(false, true, false, osmPolygon);
      }
    }
    return result;
  }
  /**
   * Write streetlight objects in dsf file.
   *
   * @param osmPolygon osm road polygon
   */
  public void writeStreetLightToDsf(OsmPolygon osmPolygon) {
    // init d'un entier pour modulo densité street lights
    Integer densityIndex = 0;
    if (XplaneOptionsHelper.getOptions().getLightsDensity() == 0) {
      densityIndex = 10;
    } else {
      if (XplaneOptionsHelper.getOptions().getLightsDensity() == 1) {
        densityIndex = 5;
      } else {
        if (XplaneOptionsHelper.getOptions().getLightsDensity() == 2) densityIndex = 3;
      }
    }
    StringBuffer sb = new StringBuffer();
    for (int i = 0; i < osmPolygon.getPolygon().getVertices().size(); i++) {
      if ((i % densityIndex) == 0) {
        Point2D lightLoc = osmPolygon.getPolygon().getVertex(i);
        lightLoc.x = lightLoc.x + 0.0001;
        lightLoc.y = lightLoc.y + 0.0001;
        if (GeomUtils.compareCoordinates(lightLoc, currentTile)) {
          Random randomGenerator = new Random();
          int orientation = randomGenerator.nextInt(360);
          sb.append(
              "OBJECT "
                  + dsfObjectsProvider.getRandomStreetLightObject()
                  + " "
                  + (lightLoc.y)
                  + " "
                  + (lightLoc.x)
                  + " "
                  + orientation);
          sb.append(System.getProperty("line.separator"));
          // stats
          StatsHelper.addStreetLight(stats);
        }
      }
    }

    writer.write(sb.toString());
  }
 /**
  * compute the dsf index of the building facade object used for a given polygon
  *
  * @param polygon
  * @param height
  * @param roofColor
  * @return
  */
 private Integer computeBuildingFacadeIndex(OsmPolygon osmPolygon) {
   Integer result = null;
   // if the polygon is a simple rectangle, we'll use a facade made for
   // simple shaped buildings
   if (osmPolygon.getPolygon().getEdges().size() == 4) {
     result = dsfObjectsProvider.computeFacadeDsfIndex(true, false, false, osmPolygon);
   }
   // the building has a complex footprint, so we'll use a facade made
   // for this case
   else {
     result = dsfObjectsProvider.computeFacadeDsfIndex(false, false, false, osmPolygon);
   }
   return result;
 }
  /**
   * Compute the height for this polygon and osm tags.
   *
   * @return Integer the height.
   */
  private Integer computeBuildingHeight(OsmPolygon polygon) {
    Integer result = null;
    Integer osmHeight = polygon.getHeight();
    if (osmHeight != null) {
      result = osmHeight;
    } else {

      if (polygon.getArea() * 10000000 < 0.2) {
        result = XplaneOptionsHelper.getOptions().getResidentialMin();
      } else {
        if (polygon.getArea() * 10000000 > ASSERTION_RESIDENTIAL_MAX_AREA)
          result =
              MiscUtils.getRandomSize(
                  XplaneOptionsHelper.getOptions().getBuildingMin(),
                  XplaneOptionsHelper.getOptions().getBuildingMax());
        else if (polygon.getArea() * 10000000 < ASSERTION_RESIDENTIAL_MAX_AREA)
          result =
              MiscUtils.getRandomSize(
                  XplaneOptionsHelper.getOptions().getResidentialMin(),
                  XplaneOptionsHelper.getOptions().getResidentialMax());
      }
    }
    return result;
  }
  /**
   * Construct and write a facade building in the dsf file.
   *
   * @param osmPolygon osm polygon
   * @return true if a building has been gennerated in the dsf file.
   */
  private boolean processBuilding(OsmPolygon osmPolygon) {
    Boolean result = false;
    if (XplaneOptionsHelper.getOptions().isGenerateBuildings()
        && OsmUtils.isBuilding(osmPolygon.getTags())
        && !OsmUtils.isExcluded(osmPolygon.getTags(), osmPolygon.getId())
        && osmPolygon.getPolygon().getVertexNumber() > BUILDING_MIN_VECTORS
        && osmPolygon.getPolygon().getVertexNumber() < BUILDING_MAX_VECTORS) {

      // check that the largest vector of the building
      // and that the area of the osmPolygon.getPolygon() are over the
      // minimum values set by the user
      Double maxVector = osmPolygon.getMaxVectorSize();
      if (maxVector > XplaneOptionsHelper.getOptions().getMinHouseSegment()
          && maxVector < XplaneOptionsHelper.getOptions().getMaxHouseSegment()
          && ((osmPolygon.getPolygon().getArea() * 100000) * 100000)
              > XplaneOptionsHelper.getOptions().getMinHouseArea()) {

        // simplify shape if checked and if necessary
        if (GuiOptionsHelper.getOptions().isSimplifyShapes() && !osmPolygon.isSimplePolygon()) {
          osmPolygon.simplifyPolygon();
        }

        // compute height and facade dsf index
        osmPolygon.setHeight(computeBuildingHeight(osmPolygon));
        Integer facade = computeFacadeIndex(osmPolygon);
        // write building in dsf file
        writeBuildingToDsf(osmPolygon, facade);
        // Smart exclusions
        if (XplaneOptionsHelper.getOptions().isSmartExclusions()) {
          exclusionsHelper.addTodoPolygon(osmPolygon);
          exclusionsHelper.run();
        }
        result = true;
      }
    }
    return result;
  }