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/*
* 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];
}
}
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