X-Git-Url: http://www2.svjatoslav.eu/gitweb/?a=blobdiff_plain;f=src%2Fmain%2Fjava%2Feu%2Fsvjatoslav%2Fsixth%2Fe3d%2Fgeometry%2FPolygon.java;h=d5f558ea5e34c3edd4b878e8e37d9891d76a175d;hb=7e383c71392e298dde478015129bc739f3eb4e4a;hp=6e23beabc81d83d26d8ec97aabec747e46da1634;hpb=59baa428fb2d9e7f0fe5423f4cea47f2d6245914;p=sixth-3d.git

diff --git a/src/main/java/eu/svjatoslav/sixth/e3d/geometry/Polygon.java b/src/main/java/eu/svjatoslav/sixth/e3d/geometry/Polygon.java
index 6e23bea..d5f558e 100644
--- a/src/main/java/eu/svjatoslav/sixth/e3d/geometry/Polygon.java
+++ b/src/main/java/eu/svjatoslav/sixth/e3d/geometry/Polygon.java
@@ -1,39 +1,43 @@
 /*
- * Sixth 3D engine. Copyright ©2012-2019, Svjatoslav Agejenko, svjatoslav@svjatoslav.eu
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 3 of the GNU Lesser General Public License
- * or later as published by the Free Software Foundation.
- *
+ * Sixth 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
  */
-
 package eu.svjatoslav.sixth.e3d.geometry;
 
+/**
+ * Utility class for polygon operations.
+ */
 public class Polygon {
 
-    private static boolean intersectsLine(final Point2D point, Point2D p1,
-                                          Point2D p2) {
 
-        if (p1.y > p2.y) {
-            final Point2D tmp = p1;
-            p1 = p2;
-            p2 = tmp;
+    /**
+     * Checks if point is on the right side of the line.
+     * @param point point to check
+     * @param lineP1 line start point
+     * @param lineP2 line end point
+     * @return true if point is on the right side of the line
+     */
+    private static boolean intersectsLine(final Point2D point, Point2D lineP1,
+                                          Point2D lineP2) {
+
+        // Sort line points by y coordinate.
+        if (lineP1.y > lineP2.y) {
+            final Point2D tmp = lineP1;
+            lineP1 = lineP2;
+            lineP2 = tmp;
         }
 
-        if (point.y < p1.y)
-            return false;
-        if (point.y > p2.y)
+        // Check if point is within line y range.
+        if (point.y < lineP1.y || point.y > lineP2.y)
             return false;
 
-        final double xp = p2.x - p1.x;
-        final double yp = p2.y - p1.y;
+        // Check if point is on the line.
+        final double xp = lineP2.x - lineP1.x;
+        final double yp = lineP2.y - lineP1.y;
 
-        final double yp2 = point.y - p1.y;
-
-        final double crossX = p1.x + ((xp * yp2) / yp);
+        final double crossX = lineP1.x + ((xp * (point.y - lineP1.y)) / yp);
 
         return point.x >= crossX;
-
     }
 
     public static boolean pointWithinPolygon(final Point2D point,