Javadocs.

diff --git a/gdx/src/com/badlogic/gdx/math/GeometryUtils.java b/gdx/src/com/badlogic/gdx/math/GeometryUtils.java
index 20dc47c..f7a1be4 100644 (file)
--- a/gdx/src/com/badlogic/gdx/math/GeometryUtils.java
+++ b/gdx/src/com/badlogic/gdx/math/GeometryUtils.java
@@ -1,13 +1,27 @@
 
 package com.badlogic.gdx.math;
 
+/** @author Nathan Sweet */
 public class GeometryUtils {
+       static private final Vector2 tmp1 = new Vector2(), tmp2 = new Vector2(), tmp3 = new Vector2();
+
        /** Computes the barycentric coordinates v,w for the specified point in the triangle.
+        * <p>
+        * If barycentric.x >= 0 && barycentric.y >= 0 && barycentric.x + barycentric.y <= 1 then the point is inside the triangle.
+        * <p>
+        * If vertices a,b,c have values aa,bb,cc then to get an interpolated value at point p:
+        * 
+        * <pre>
+        * GeometryUtils.barycentric(p, a, b, c, barycentric);
+        * float u = 1.f - barycentric.x - barycentric.y;
+        * float x = u * aa.x + barycentric.x * bb.x + barycentric.y * cc.x;
+        * float y = u * aa.y + barycentric.x * bb.y + barycentric.y * cc.y;
+        * </pre>
         * @return barycentricOut */
        static public Vector2 barycentric (Vector2 p, Vector2 a, Vector2 b, Vector2 c, Vector2 barycentricOut) {
-               Vector2 v0 = b.sub(a);
-               Vector2 v1 = c.sub(a);
-               Vector2 v2 = p.sub(a);
+               Vector2 v0 = tmp1.set(b).sub(a);
+               Vector2 v1 = tmp2.set(c).sub(a);
+               Vector2 v2 = tmp3.set(p).sub(a);
                float d00 = v0.dot(v0);
                float d01 = v0.dot(v1);
                float d11 = v1.dot(v1);

diff --git a/gdx/src/com/badlogic/gdx/math/Intersector.java b/gdx/src/com/badlogic/gdx/math/Intersector.java
index 88238c1..a9e614f 100644 (file)
--- a/gdx/src/com/badlogic/gdx/math/Intersector.java
+++ b/gdx/src/com/badlogic/gdx/math/Intersector.java
@@ -59,6 +59,16 @@ public final class Intersector {
        }
 
        /** Returns true if the given point is inside the triangle. */
+       public static boolean isPointInTriangle (Vector2 p, Vector2 a, Vector2 b, Vector2 c) {
+               float px1 = p.x - a.x;
+               float py1 = p.y - a.y;
+               boolean side12 = (b.x - a.x) * py1 - (b.y - a.y) * px1 > 0;
+               if ((c.x - a.x) * py1 - (c.y - a.y) * px1 > 0 == side12) return false;
+               if ((c.x - b.x) * (p.y - b.y) - (c.y - b.y) * (p.x - b.x) > 0 != side12) return false;
+               return true;
+       }
+
+       /** Returns true if the given point is inside the triangle. */
        public static boolean isPointInTriangle (float px, float py, float ax, float ay, float bx, float by, float cx, float cy) {
                float px1 = px - ax;
                float py1 = py - ay;
@@ -92,26 +102,24 @@ public final class Intersector {
                        * (pointX - linePoint1X));
        }
 
-    /** Checks whether the given point is in the polygon.
-     * @param polygon The polygon vertices passed as an array
-     * @param point The point
-     * @return true if the point is in the polygon */
-   public static boolean isPointInPolygon (Array<Vector2> polygon, Vector2 point) {
-        Vector2 lastVertice = polygon.peek();
-        boolean oddNodes = false;
-        for (int i=0; i<polygon.size; i++) {
-            Vector2 vertice = polygon.get(i);
-            if (vertice.y < point.y && lastVertice.y >= point.y || lastVertice.y < point.y
-                    && vertice.y >= point.y) {
-                if (vertice.x + (point.y - vertice.y) / (lastVertice.y - vertice.y)
-                        * (lastVertice.x - vertice.x) < point.x) {
-                    oddNodes = !oddNodes;
-                }
-            }
-            lastVertice = vertice;
-        }
-        return oddNodes;
-    }
+       /** Checks whether the given point is in the polygon.
+        * @param polygon The polygon vertices passed as an array
+        * @param point The point
+        * @return true if the point is in the polygon */
+       public static boolean isPointInPolygon (Array<Vector2> polygon, Vector2 point) {
+               Vector2 lastVertice = polygon.peek();
+               boolean oddNodes = false;
+               for (int i = 0; i < polygon.size; i++) {
+                       Vector2 vertice = polygon.get(i);
+                       if (vertice.y < point.y && lastVertice.y >= point.y || lastVertice.y < point.y && vertice.y >= point.y) {
+                               if (vertice.x + (point.y - vertice.y) / (lastVertice.y - vertice.y) * (lastVertice.x - vertice.x) < point.x) {
+                                       oddNodes = !oddNodes;
+                               }
+                       }
+                       lastVertice = vertice;
+               }
+               return oddNodes;
+       }
 
        /** Returns true if the specified point is in the polygon. */
        public static boolean isPointInPolygon (float[] polygon, int offset, int count, float x, float y) {