1 files changed, 56 insertions, 0 deletions
diff --git a/src/3rdparty/resonance-audio/resonance_audio/dsp/mixer.cc b/src/3rdparty/resonance-audio/resonance_audio/dsp/mixer.cc
new file mode 100644
index 000000000..1b7460428
--- /dev/null
+++ b/src/3rdparty/resonance-audio/resonance_audio/dsp/mixer.cc
@@ -0,0 +1,56 @@
+/*
+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/mixer.h"
+
+#include "base/logging.h"
+
+namespace vraudio {
+
+Mixer::Mixer(size_t target_num_channels, size_t frames_per_buffer)
+    : output_(target_num_channels, frames_per_buffer), is_empty_(false) {
+  Reset();
+}
+
+void Mixer::AddInput(const AudioBuffer& input) {
+  DCHECK_EQ(input.num_frames(), output_.num_frames());
+
+  // Accumulate the input buffers into the output buffer.
+  const size_t num_channels =
+      std::min(input.num_channels(), output_.num_channels());
+  for (size_t n = 0; n < num_channels; ++n) {
+    if (input[n].IsEnabled()) {
+      output_[n] += input[n];
+    }
+  }
+  is_empty_ = false;
+}
+
+const AudioBuffer* Mixer::GetOutput() const {
+  if (is_empty_) {
+    return nullptr;
+  }
+  return &output_;
+}
+
+void Mixer::Reset() {
+  if (!is_empty_) {
+    output_.Clear();
+  }
+  is_empty_ = true;
+}
+
+}  // namespace vraudio