1 files changed, 46 insertions, 0 deletions
diff --git a/src/3rdparty/resonance-audio/resonance_audio/dsp/stereo_panner.cc b/src/3rdparty/resonance-audio/resonance_audio/dsp/stereo_panner.cc
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index 000000000..373db9989
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+++ b/src/3rdparty/resonance-audio/resonance_audio/dsp/stereo_panner.cc
@@ -0,0 +1,46 @@
+/*
+Copyright 2018 Google Inc. All Rights Reserved.
+
+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.
+*/
+
+#include "dsp/stereo_panner.h"
+
+#include <cmath>
+
+#include "base/constants_and_types.h"
+
+namespace vraudio {
+
+const float kStereoLeftRadians = kRadiansFromDegrees * kStereoLeftDegrees;
+const float kStereoRightRadians = kRadiansFromDegrees * kStereoRightDegrees;
+
+void CalculateStereoPanGains(const SphericalAngle& source_direction,
+                             std::vector<float>* stereo_gains) {
+  // Note this applies the same panning law as was applied by the ambisonic
+  // equivalent panner to ensure consistency.
+  DCHECK(stereo_gains);
+  stereo_gains->resize(kNumStereoChannels);
+
+  const float cos_direction_elevation = std::cos(source_direction.elevation());
+
+  (*stereo_gains)[0] =
+      0.5f * (1.0f + std::cos(kStereoLeftRadians - source_direction.azimuth()) *
+                         cos_direction_elevation);
+  (*stereo_gains)[1] =
+      0.5f *
+      (1.0f + std::cos(kStereoRightRadians - source_direction.azimuth()) *
+                  cos_direction_elevation);
+}
+
+}  // namespace vraudio