1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.example.android.rs.vr.engine; 18 19 /** 20 * Some minimal utilities for Vector math 21 */ 22 public class VectorUtil { sub(double[] a, double[] b, double[] out)23 public static void sub(double[] a, double[] b, double[] out) { 24 out[0] = a[0] - b[0]; 25 out[1] = a[1] - b[1]; 26 out[2] = a[2] - b[2]; 27 } 28 mult(double[] a, double b, double[] out)29 public static void mult(double[] a, double b, double[] out) { 30 out[0] = a[0] * b; 31 out[1] = a[1] * b; 32 out[2] = a[2] * b; 33 } 34 dot(double[] a, double[] b)35 public static double dot(double[] a, double[] b) { 36 return a[0] * b[0] + a[1] * b[1] + a[2] * b[2]; 37 } 38 norm(double[] a)39 public static double norm(double[] a) { 40 return Math.sqrt(a[0] * a[0] + a[1] * a[1] + a[2] * a[2]); 41 } 42 cross(double[] a, double[] b, double[] out)43 public static void cross(double[] a, double[] b, double[] out) { 44 double out0 = a[1] * b[2] - b[1] * a[2]; 45 double out1 = a[2] * b[0] - b[2] * a[0]; 46 double out2 = a[0] * b[1] - b[0] * a[1]; 47 out[0] = out0; 48 out[1] = out1; 49 out[2] = out2; 50 } 51 normalize(double[] a)52 public static void normalize(double[] a) { 53 double norm = norm(a); 54 a[0] /= norm; 55 a[1] /= norm; 56 a[2] /= norm; 57 } 58 add(double[] a, double[] b, double[] out)59 public static void add(double[] a, double[] b, 60 double[] out) { 61 out[0] = a[0] + b[0]; 62 out[1] = a[1] + b[1]; 63 out[2] = a[2] + b[2]; 64 } 65 66 } 67