1 /*
2  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_ARRAY_UTIL_H_
12 #define WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_ARRAY_UTIL_H_
13 
14 #include <cmath>
15 #include <vector>
16 
17 #include "webrtc/base/maybe.h"
18 
19 namespace webrtc {
20 
21 // Coordinates in meters. The convention used is:
22 // x: the horizontal dimension, with positive to the right from the camera's
23 //    perspective.
24 // y: the depth dimension, with positive forward from the camera's
25 //    perspective.
26 // z: the vertical dimension, with positive upwards.
27 template<typename T>
28 struct CartesianPoint {
29   CartesianPoint() {
30     c[0] = 0;
31     c[1] = 0;
32     c[2] = 0;
33   }
34   CartesianPoint(T x, T y, T z) {
35     c[0] = x;
36     c[1] = y;
37     c[2] = z;
38   }
39   T x() const { return c[0]; }
40   T y() const { return c[1]; }
41   T z() const { return c[2]; }
42   T c[3];
43 };
44 
45 using Point = CartesianPoint<float>;
46 
47 // Calculates the direction from a to b.
48 Point PairDirection(const Point& a, const Point& b);
49 
50 float DotProduct(const Point& a, const Point& b);
51 Point CrossProduct(const Point& a, const Point& b);
52 
53 bool AreParallel(const Point& a, const Point& b);
54 bool ArePerpendicular(const Point& a, const Point& b);
55 
56 // Returns the minimum distance between any two Points in the given
57 // |array_geometry|.
58 float GetMinimumSpacing(const std::vector<Point>& array_geometry);
59 
60 // If the given array geometry is linear it returns the direction without
61 // normalizing.
62 rtc::Maybe<Point> GetDirectionIfLinear(
63     const std::vector<Point>& array_geometry);
64 
65 // If the given array geometry is planar it returns the normal without
66 // normalizing.
67 rtc::Maybe<Point> GetNormalIfPlanar(const std::vector<Point>& array_geometry);
68 
69 // Returns the normal of an array if it has one and it is in the xy-plane.
70 rtc::Maybe<Point> GetArrayNormalIfExists(
71     const std::vector<Point>& array_geometry);
72 
73 // The resulting Point will be in the xy-plane.
74 Point AzimuthToPoint(float azimuth);
75 
76 template<typename T>
77 float Distance(CartesianPoint<T> a, CartesianPoint<T> b) {
78   return std::sqrt((a.x() - b.x()) * (a.x() - b.x()) +
79                    (a.y() - b.y()) * (a.y() - b.y()) +
80                    (a.z() - b.z()) * (a.z() - b.z()));
81 }
82 
83 // The convention used:
84 // azimuth: zero is to the right from the camera's perspective, with positive
85 //          angles in radians counter-clockwise.
86 // elevation: zero is horizontal, with positive angles in radians upwards.
87 // radius: distance from the camera in meters.
88 template <typename T>
89 struct SphericalPoint {
90   SphericalPoint(T azimuth, T elevation, T radius) {
91     s[0] = azimuth;
92     s[1] = elevation;
93     s[2] = radius;
94   }
95   T azimuth() const { return s[0]; }
96   T elevation() const { return s[1]; }
97   T distance() const { return s[2]; }
98   T s[3];
99 };
100 
101 using SphericalPointf = SphericalPoint<float>;
102 
103 // Helper functions to transform degrees to radians and the inverse.
104 template <typename T>
105 T DegreesToRadians(T angle_degrees) {
106   return M_PI * angle_degrees / 180;
107 }
108 
109 template <typename T>
110 T RadiansToDegrees(T angle_radians) {
111   return 180 * angle_radians / M_PI;
112 }
113 
114 }  // namespace webrtc
115 
116 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_ARRAY_UTIL_H_
117