public List<Triangle> parseFile(InputStream is) {
try {
VTDGen vg = new VTDGen();
vg.setDoc(IOUtils.toByteArray(is));
vg.parse(false);
VTDNav vn = vg.getNav();
NODE_PATH.resetXPath();
NODE_PATH.bind(vn); // This is important state for the later method calls!
NODE_REF_PATH.resetXPath();
NODE_REF_PATH.bind(vn);
BUILDING_WAY_PATH.resetXPath();
BUILDING_WAY_PATH.bind(vn);
BUILDING_MULTIPOLYGON_PATH.resetXPath();
BUILDING_MULTIPOLYGON_PATH.bind(vn);
MEMBER_WAY_PATH.resetXPath();
MEMBER_WAY_PATH.bind(vn);
WAY_PATH.resetXPath();
WAY_PATH.bind(vn);
// A hash from node ids to actual node positions
Hashtable<Long, Point2D> nodes = new Hashtable<>();
// A hash from way refs referenced from multipolygons to their actual list of node refs
Hashtable<Long, List<Long>> multipolygonWays = new Hashtable<>();
// The following call initializes accessed node refs in nodes to a dummy value.
List<List<Long>> buildingWays = extractWaysOfBuildings(vn, nodes);
// The following call initializes accessed way refs from multipolygons to a dummy value.
List<List<Tuple2<WayRole, Long>>> multipolygonWayRefs =
extractWayRefsOfMultipolygons(vn, multipolygonWays);
// This will extract all referenced multipolygon multipolygonWays, excluding the building
// multipolygonWays
// Also adds referenced nodes to nodes
extractReferencedWays(vn, multipolygonWays, nodes);
// This will extract all referenced nodes, but no more.
extractReferencedNodes(vn, nodes);
// Finally build the polygon list by following the node refs in wayRefs.
// Triangulate each polygon and return the flattened list of triangles.
// This way, poly2tri's types will not leak out of this class and we operate
// on triangles anyway.
return buildPolygons(nodes, buildingWays, multipolygonWays, multipolygonWayRefs)
.flatMap(
p -> {
try {
p.ComplexToSimplePolygon();
EarClipping ec = new EarClipping(p.SimplePolygon);
return ec.Triangulation().stream();
} catch (RuntimeException ignored) {
}
return Stream.empty();
})
.toList();
} catch (XPathEvalException | NavException | IOException | ParseException e) {
e.printStackTrace();
return new ArrayList<>();
}
}
public static void main(String args[]) {
try {
VTDGen vg = new VTDGen();
if (vg.parseFile("po.xml", true)) {
// recommended extension is .vxl
vg.writeIndex("po.vxl");
}
} catch (Exception e) {
}
}
