Refactor: Change intersection method

CityDoctorParent/CityDoctorValidation/src/main/java/de/hft/stuttgart/citydoctor2/checks/topology/FeatureCollisionCheck.java

@@ -168,7 +168,8 @@ public class FeatureCollisionCheck extends Check{
     }
 
     private List<Pair<Polygon,Polygon>> getCollisionPairs(Geometry subjectGeom, Geometry candidateGeom){
-        List<PolygonIntersection> intersections = getPolygonIntersections(subjectGeom, candidateGeom);
+        List<PolygonIntersection> intersections = SelfIntersectionUtil
+                .calculateGeometryIntersections(subjectGeom, candidateGeom, epsilon);
         return intersections.stream()
                         .filter( polySect -> polySect.getType() != PolygonIntersection.IntersectionType.NONE)
                         .map(polySect -> new Pair<>(polySect.getP1(), polySect.getP2()))

CityDoctorParent/CityDoctorValidation/src/main/java/de/hft/stuttgart/citydoctor2/checks/util/SelfIntersectionUtil.java

@@ -84,7 +84,37 @@ public class SelfIntersectionUtil {
 	private SelfIntersectionUtil() {
 
 	}
-	
+
+	public static List<PolygonIntersection> calculateGeometryIntersections(Geometry subject, Geometry candidate, double delta){
+		List<TesselatedPolygon> tesselatedSubjectPolygons = tessellateGeometry(subject, delta);
+		List<TesselatedPolygon> tesselatedCandidatePolygons = tessellateGeometry(candidate, delta);
+		List<PolygonIntersection> intersections = new ArrayList<>();
+		for (TesselatedPolygon sPoly : tesselatedSubjectPolygons) {
+			for (TesselatedPolygon cPoly : tesselatedCandidatePolygons) {
+				GeometrySelfIntersection intersection = doPolygonsIntersect(sPoly, cPoly, delta);
+				if (intersection != null) {
+					intersections.add(PolygonIntersection.triangles(intersection.t1(), intersection.t2()));
+				}
+			}
+		}
+		return intersections;
+	}
+
+	private static List<TesselatedPolygon> tessellateGeometry(Geometry geom, double delta){
+		List<TesselatedPolygon> tesselatedPolygons = new ArrayList<>();
+		for (Polygon p : geom.getPolygons()) {
+			TesselatedPolygon tessPolygon = EarcutTesselator.tesselatePolygon(p);
+			for (Iterator<Triangle3d> iterator = tessPolygon.getTriangles().iterator(); iterator.hasNext();) {
+				Triangle3d t = iterator.next();
+				if (!t.hasMinExtent(delta)) {
+					iterator.remove();
+				}
+			}
+			tesselatedPolygons.add(tessPolygon);
+		}
+		return tesselatedPolygons;
+	}
+
 	public static List<PolygonIntersection> calculateSolidSelfIntersection(Geometry g, double delta) {
 		List<TesselatedPolygon> tesselatedPolygons = new ArrayList<>();
 		for (Polygon p : g.getPolygons()) {