1 files changed, 52 insertions, 0 deletions
diff --git a/src/3rdparty/resonance-audio/resonance_audio/dsp/occlusion_calculator.cc b/src/3rdparty/resonance-audio/resonance_audio/dsp/occlusion_calculator.cc
new file mode 100644
index 000000000..9c8d92c1b
--- /dev/null
+++ b/src/3rdparty/resonance-audio/resonance_audio/dsp/occlusion_calculator.cc
@@ -0,0 +1,52 @@
+/*
+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/occlusion_calculator.h"
+
+#include <cmath>
+
+#include "base/logging.h"
+#include "base/misc_math.h"
+
+namespace vraudio {
+
+float CalculateDirectivity(float alpha, float order,
+                           const SphericalAngle& spherical_angle) {
+  // Clamp alpha weighting.
+  const float alpha_clamped = std::min(std::max(alpha, 0.0f), 1.0f);
+
+  // Check for zero-valued alpha (omnidirectional).
+  if (alpha_clamped < std::numeric_limits<float>::epsilon()) {
+    return 1.0f;
+  } else {
+    const float gain = (1.0f - alpha_clamped) +
+                       alpha_clamped * (std::cos(spherical_angle.azimuth()) *
+                                        std::cos(spherical_angle.elevation()));
+
+    return std::pow(std::abs(gain), std::max(order, 1.0f));
+  }
+}
+
+float CalculateOcclusionFilterCoefficient(float directivity,
+                                          float occlusion_intensity) {
+  DCHECK_GE(occlusion_intensity, 0.0f);
+
+  const float occlusion_factor =
+      1.0f / IntegerPow(occlusion_intensity + 1.0f, 4);
+  return std::max(0.0f, 1.0f - directivity * occlusion_factor);
+}
+
+}  // namespace vraudio