Move dead submodules in-tree

Signed-off-by: swurl <swurl@swurl.xyz>

externals/oboe/samples/shared/Mixer.h

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#ifndef SHARED_MIXER_H
+#define SHARED_MIXER_H
+
+#include <array>
+#include "IRenderableAudio.h"
+
+/**
+ * A Mixer object which sums the output from multiple tracks into a single output. The number of
+ * input channels on each track must match the number of output channels (default 1=mono). This can
+ * be changed by calling `setChannelCount`.
+ * The inputs to the mixer are not owned by the mixer, they should not be deleted while rendering.
+ */
+class Mixer : public IRenderableAudio {
+
+public:
+    void renderAudio(float *audioData, int32_t numFrames) {
+
+        int numSamples = numFrames * mChannelCount;
+        if (numSamples > mBufferSize) {
+            mMixingBuffer = std::make_unique<float[]>(numSamples);
+            mBufferSize = numSamples;
+        }
+
+        // Zero out the incoming container array
+        memset(audioData, 0, sizeof(float) * numSamples);
+
+        for (int i = 0; i < mTracks.size(); ++i) {
+            mTracks[i]->renderAudio(mMixingBuffer.get(), numFrames);
+
+            for (int j = 0; j < numSamples; ++j) {
+                audioData[j] += mMixingBuffer[j];
+            }
+        }
+    }
+
+    void addTrack(IRenderableAudio *renderer){
+        mTracks.push_back(renderer);
+    }
+
+    void setChannelCount(int32_t channelCount){ mChannelCount = channelCount; }
+
+    void removeAllTracks(){
+        mTracks.clear();
+    }
+
+private:
+    int32_t mBufferSize = 0;
+    std::unique_ptr<float[]> mMixingBuffer;
+    std::vector<IRenderableAudio*> mTracks;
+    int32_t mChannelCount = 1; // Default to mono
+};
+
+
+#endif //SHARED_MIXER_H