Make the nonlinear beamformer steerable

webrtc/modules/audio_processing/beamformer/array_util.h

Index: webrtc/modules/audio_processing/beamformer/array_util.h
diff --git a/webrtc/modules/audio_processing/beamformer/array_util.h b/webrtc/modules/audio_processing/beamformer/array_util.h
index 2ac174ea8aa04800995551d03017c9d215415921..1291ba90968decdce534bbb9b3ab86a43882d2ff 100644
--- a/webrtc/modules/audio_processing/beamformer/array_util.h
+++ b/webrtc/modules/audio_processing/beamformer/array_util.h
@@ -16,7 +16,12 @@
 
 namespace webrtc {
 
-// Coordinates in meters.
+// Coordinates in meters. The convention used is:
+// x: the horizontal dimension, with positive to the right from the camera's
+//    perspective.
+// y: the depth dimension, with positive forward from the camera's
+//    perspective.
+// z: the vertical dimension, with positive upwards.
 template<typename T>
 struct CartesianPoint {
   CartesianPoint(T x, T y, T z) {
@@ -43,6 +48,11 @@ float Distance(CartesianPoint<T> a, CartesianPoint<T> b) {
                    (a.z() - b.z()) * (a.z() - b.z()));
 }
 
+// The convention used:
+// azimuth: zero is to the right from the camera's perspective, with positive
+//          angles in radians counter-clockwise.
+// elevation: zero is horizontal, with positive angles in radians upwards.
+// radius: distance from the camera in meters.
 template <typename T>
 struct SphericalPoint {
   SphericalPoint(T azimuth, T elevation, T radius) {
@@ -58,6 +68,10 @@ struct SphericalPoint {
 
 using SphericalPointf = SphericalPoint<float>;
 
+// Helper functions to transform degrees to radians and the inverse.
+float DegreesToRadians(float angle_degrees);

[Andrew MacDonald, 2015/10/21 03:27:43]

Probably reasonable to make these templates.

[aluebs-webrtc, 2015/10/27 18:08:15]

Done.

+float RadiansToDegrees(float angle_radians);
+
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_ARRAY_UTIL_H_