Add OrientationFP functions

modules/app/src/main/java/org/locationtech/jtstest/function/OrientationFPFunctions.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2017 Martin Davis.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * and Eclipse Distribution License v. 1.0 which accompanies this distribution.
+ * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
+ * and the Eclipse Distribution License is available at
+ *
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ */
+package org.locationtech.jtstest.function;
+
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.Geometry;
+
+public class OrientationFPFunctions {
+
+  public static int orientationIndex(Geometry segment, Geometry ptGeom) {
+    if (segment.getNumPoints() != 2 || ptGeom.getNumPoints() != 1) {
+      throw new IllegalArgumentException("A must have two points and B must have one");
+    }
+    Coordinate[] segPt = segment.getCoordinates();
+
+    Coordinate p = ptGeom.getCoordinate();
+    int index = orientationIndex(segPt[0], segPt[1], p);
+    return index;
+  }
+
+  private static int orientationIndex(Coordinate p1, Coordinate p2, Coordinate q)
+  {
+        double dx1 = p2.x - p1.x;
+        double dy1 = p2.y - p1.y;
+        double dx2 = q.x - p2.x;
+        double dy2 = q.y - p2.y;
+        double det = dx1*dy2 - dx2*dy1;
+        if (det > 0.0) return 1;
+        if (det < 0.0) return -1;
+        return 0;
+  }
+}

modules/app/src/main/java/org/locationtech/jtstest/geomfunction/GeometryFunctionRegistry.java

@@ -45,6 +45,7 @@
 import org.locationtech.jtstest.function.LinearReferencingFunctions;
 import org.locationtech.jtstest.function.NodingFunctions;
 import org.locationtech.jtstest.function.OffsetCurveFunctions;
+import org.locationtech.jtstest.function.OrientationFPFunctions;
 import org.locationtech.jtstest.function.OrientationFunctions;
 import org.locationtech.jtstest.function.OverlayFunctions;
 import org.locationtech.jtstest.function.OverlayNGFunctions;
@@ -120,6 +121,7 @@ public static GeometryFunctionRegistry createTestBuilderRegistry()
     //funcRegistry.add(MemoryFunctions.class);
     funcRegistry.add(OffsetCurveFunctions.class);
     funcRegistry.add(OrientationFunctions.class);
+    funcRegistry.add(OrientationFPFunctions.class);
     funcRegistry.add(LineSegmentFunctions.class);
     funcRegistry.add(OverlayFunctions.class);