Adding method IsInBeam to beamformer class.

webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc

Index: webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc
diff --git a/webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc b/webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc
index 1e03c853fe05909eb4a98251b1c8b097578301f9..f3fc6b2175241bf6e118fa9e57e3829d49852287 100644
--- a/webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc
+++ b/webrtc/modules/audio_processing/beamformer/nonlinear_beamformer.cc
@@ -50,6 +50,9 @@ const float kInterfAngleRadians = static_cast<float>(M_PI) / 4.f;
 // Rpsi = Rpsi_angled * kBalance + Rpsi_uniform * (1 - kBalance)
 const float kBalance = 0.4f;
 
+// The width of half of the beam in radians.
+const float kBeamWidthAngle = static_cast<float>(M_PI)20.f / 180.f;

[aluebs-webrtc, 2015/06/25 01:04:36]

const float kBeamWidthAngle = static_cast<float>(M_PI) * 20.f / 180.f;

[Andrew MacDonald, 2015/06/26 02:04:24]

I think you can omit the cast.

[bloch, 2015/06/26 03:37:28]

I tried it without the cast and there were some compiler errors when I ran "git
cl try"

[Andrew MacDonald, 2015/06/26 03:46:09]

OK, thanks for trying.

+
 // TODO(claguna): need comment here.
 const float kBeamwidthConstant = 0.00002f;
 
@@ -334,6 +337,12 @@ void NonlinearBeamformer::ProcessChunk(const ChannelBuffer<float>& input,
   }
 }
 
+bool NonlinearBeamformer::IsInBeam(float azimuth) {
+  // If more than half-beamwidth degrees away from the beam's center,
+  // you are out of the beam.
+  return fabs(azimuth - kTargetAngleRadians) < kBeamWidthAngle;
+}
+
 void NonlinearBeamformer::ProcessAudioBlock(const complex_f* const* input,
                                             int num_input_channels,
                                             int num_freq_bins,