1 files changed, 82 insertions, 0 deletions
diff --git a/src/3rdparty/resonance-audio/resonance_audio/graph/gain_node.cc b/src/3rdparty/resonance-audio/resonance_audio/graph/gain_node.cc
new file mode 100644
index 000000000..ca1c8edb2
--- /dev/null
+++ b/src/3rdparty/resonance-audio/resonance_audio/graph/gain_node.cc
@@ -0,0 +1,82 @@
+/*
+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 "graph/gain_node.h"
+
+#include <cmath>
+
+
+#include "dsp/gain.h"
+
+namespace vraudio {
+
+GainNode::GainNode(SourceId source_id, size_t num_channels,
+                   const AttenuationType& attenuation_type,
+                   const SystemSettings& system_settings)
+    : num_channels_(num_channels),
+      attenuation_type_(attenuation_type),
+      gain_processors_(num_channels_),
+      system_settings_(system_settings),
+      output_buffer_(num_channels, system_settings.GetFramesPerBuffer()) {
+  DCHECK_GT(num_channels, 0U);
+  output_buffer_.set_source_id(source_id);
+}
+
+const AudioBuffer* GainNode::AudioProcess(const NodeInput& input) {
+
+
+  const AudioBuffer* input_buffer = input.GetSingleInput();
+  DCHECK(input_buffer);
+  DCHECK_EQ(input_buffer->num_channels(), num_channels_);
+  DCHECK_EQ(input_buffer->source_id(), output_buffer_.source_id());
+
+  const auto source_parameters =
+      system_settings_.GetSourceParameters(input_buffer->source_id());
+  if (source_parameters == nullptr) {
+    LOG(WARNING) << "Could not find source parameters";
+    return nullptr;
+  }
+
+  const float current_gain = gain_processors_[0].GetGain();
+  const float target_gain = source_parameters->attenuations[attenuation_type_];
+  if (IsGainNearZero(target_gain) && IsGainNearZero(current_gain)) {
+    // Make sure the gain processors are initialized.
+    for (size_t i = 0; i < num_channels_; ++i) {
+      gain_processors_[i].Reset(0.0f);
+    }
+    // Skip processing in case of zero gain.
+    return nullptr;
+  }
+  if (IsGainNearUnity(target_gain) && IsGainNearUnity(current_gain)) {
+    // Make sure the gain processors are initialized.
+    for (size_t i = 0; i < num_channels_; ++i) {
+      gain_processors_[i].Reset(1.0f);
+    }
+    // Skip processing in case of unity gain.
+    return input_buffer;
+  }
+
+  // Apply the gain to each input buffer channel.
+  for (size_t i = 0; i < num_channels_; ++i) {
+    gain_processors_[i].ApplyGain(target_gain, (*input_buffer)[i],
+                                  &output_buffer_[i],
+                                  false /* accumulate_output */);
+  }
+
+  return &output_buffer_;
+}
+
+}  // namespace vraudio