Vec3: add 2 static add() methods

src/main/java/com/github/stephengold/joltjni/Vec3.java

@@ -103,6 +103,39 @@ public Vec3(float[] array) {
     // *************************************************************************
     // new methods exposed
 
+    /**
+     * Return the component-wise sum of the specified vectors.
+     *
+     * @param v1 the first vector (not null, unaffected)
+     * @param v2 the 2nd vector (not null, unaffected)
+     * @return a new vector
+     */
+    public static Vec3 add(Vec3Arg v1, Vec3Arg v2) {
+        float x = v1.getX() + v2.getX();
+        float y = v1.getY() + v2.getY();
+        float z = v1.getZ() + v2.getZ();
+        Vec3 result = new Vec3(x, y, z);
+
+        return result;
+    }
+
+    /**
+     * Return the component-wise sum of the specified vectors.
+     *
+     * @param v1 the first vector (not null, unaffected)
+     * @param v2 the 2nd vector (not null, unaffected)
+     * @param v3 the 3nd vector (not null, unaffected)
+     * @return a new vector
+     */
+    public static Vec3 add(Vec3Arg v1, Vec3Arg v2, Vec3Arg v3) {
+        float x = v1.getX() + v2.getX() + v3.getX();
+        float y = v1.getY() + v2.getY() + v3.getY();
+        float z = v1.getZ() + v2.getZ() + v3.getZ();
+        Vec3 result = new Vec3(x, y, z);
+
+        return result;
+    }
+
     /**
      * Return a scaled version of the specified vector.
      *