1 files changed, 66 insertions, 0 deletions
diff --git a/java/tests/VrDemo/src/com/example/android/rs/vr/engine/VectorUtil.java b/java/tests/VrDemo/src/com/example/android/rs/vr/engine/VectorUtil.java
new file mode 100644
index 00000000..973d705f
--- /dev/null
+++ b/java/tests/VrDemo/src/com/example/android/rs/vr/engine/VectorUtil.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.rs.vr.engine;
+
+/**
+ * Some minimal utilities for Vector math
+ */
+public class VectorUtil {
+    public static void sub(double[] a, double[] b, double[] out) {
+        out[0] = a[0] - b[0];
+        out[1] = a[1] - b[1];
+        out[2] = a[2] - b[2];
+    }
+
+    public static void mult(double[] a, double b, double[] out) {
+        out[0] = a[0] * b;
+        out[1] = a[1] * b;
+        out[2] = a[2] * b;
+    }
+
+    public static double dot(double[] a, double[] b) {
+        return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
+    }
+
+    public static double norm(double[] a) {
+        return Math.sqrt(a[0] * a[0] + a[1] * a[1] + a[2] * a[2]);
+    }
+
+    public static void cross(double[] a, double[] b, double[] out) {
+        double out0 = a[1] * b[2] - b[1] * a[2];
+        double out1 = a[2] * b[0] - b[2] * a[0];
+        double out2 = a[0] * b[1] - b[0] * a[1];
+        out[0] = out0;
+        out[1] = out1;
+        out[2] = out2;
+    }
+
+    public static void normalize(double[] a) {
+        double norm = norm(a);
+        a[0] /= norm;
+        a[1] /= norm;
+        a[2] /= norm;
+    }
+
+    public static void add(double[] a, double[] b,
+                           double[] out) {
+        out[0] = a[0] + b[0];
+        out[1] = a[1] + b[1];
+        out[2] = a[2] + b[2];
+    }
+
+}