1 files changed, 51 insertions, 0 deletions
diff --git a/externals/oboe/samples/hello-oboe/src/main/cpp/SoundGenerator.cpp b/externals/oboe/samples/hello-oboe/src/main/cpp/SoundGenerator.cpp
new file mode 100644
index 0000000000..1de9030f28
--- /dev/null
+++ b/externals/oboe/samples/hello-oboe/src/main/cpp/SoundGenerator.cpp
@@ -0,0 +1,51 @@
+/*
+ * 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.
+ */
+
+#include "SoundGenerator.h"
+
+SoundGenerator::SoundGenerator(int32_t sampleRate, int32_t channelCount) :
+        TappableAudioSource(sampleRate, channelCount)
+        , mOscillators(std::make_unique<Oscillator[]>(channelCount)){
+
+    double frequency = 440.0;
+    constexpr double interval = 110.0;
+    constexpr float amplitude = 1.0;
+
+    // Set up the oscillators
+    for (int i = 0; i < mChannelCount; ++i) {
+        mOscillators[i].setFrequency(frequency);
+        mOscillators[i].setSampleRate(mSampleRate);
+        mOscillators[i].setAmplitude(amplitude);
+        frequency += interval;
+    }
+}
+
+void SoundGenerator::renderAudio(float *audioData, int32_t numFrames) {
+    // Render each oscillator into its own channel
+    std::fill_n(mBuffer.get(), kSharedBufferSize, 0);
+    for (int i = 0; i < mChannelCount; ++i) {
+        mOscillators[i].renderAudio(mBuffer.get(), numFrames);
+        for (int j = 0; j < numFrames; ++j) {
+            audioData[(j * mChannelCount) + i] = mBuffer[j];
+        }
+    }
+}
+
+void SoundGenerator::tap(bool isOn) {
+    for (int i = 0; i < mChannelCount; ++i) {
+        mOscillators[i].setWaveOn(isOn);
+    }
+}