1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef SINE_GENERATOR_H 18 #define SINE_GENERATOR_H 19 20 #include <math.h> 21 22 class SineGenerator 23 { 24 public: SineGenerator()25 SineGenerator() {} 26 virtual ~SineGenerator() = default; 27 setup(double frequency,double frameRate)28 void setup(double frequency, double frameRate) { 29 mFrameRate = frameRate; 30 mPhaseIncrement = frequency * M_PI * 2 / frameRate; 31 } 32 setSweep(double frequencyLow,double frequencyHigh,double seconds)33 void setSweep(double frequencyLow, double frequencyHigh, double seconds) { 34 mSweeping = seconds > 0.0; 35 if (mSweeping) { 36 mPhaseIncrementLow = frequencyLow * M_PI * 2 / mFrameRate; 37 mPhaseIncrementHigh = frequencyHigh * M_PI * 2 / mFrameRate; 38 double numFrames = seconds * mFrameRate; 39 mUpScaler = pow((frequencyHigh / frequencyLow), (1.0 / numFrames)); 40 mDownScaler = 1.0 / mUpScaler; 41 } 42 } 43 render(int16_t * buffer,int32_t channelStride,int32_t numFrames)44 void render(int16_t *buffer, int32_t channelStride, int32_t numFrames) { 45 int sampleIndex = 0; 46 for (int i = 0; i < numFrames; i++) { 47 buffer[sampleIndex] = (int16_t) (INT16_MAX * sin(mPhase) * mAmplitude); 48 sampleIndex += channelStride; 49 advancePhase(); 50 } 51 } render(float * buffer,int32_t channelStride,int32_t numFrames)52 void render(float *buffer, int32_t channelStride, int32_t numFrames) { 53 int sampleIndex = 0; 54 for (int i = 0; i < numFrames; i++) { 55 buffer[sampleIndex] = sin(mPhase) * mAmplitude; 56 sampleIndex += channelStride; 57 advancePhase(); 58 } 59 } 60 setAmplitude(double amplitude)61 void setAmplitude(double amplitude) { 62 mAmplitude = amplitude; 63 } 64 getAmplitude()65 double getAmplitude() const { 66 return mAmplitude; 67 } 68 69 private: advancePhase()70 void advancePhase() { 71 mPhase += mPhaseIncrement; 72 if (mPhase > M_PI * 2) { 73 mPhase -= M_PI * 2; 74 } 75 if (mSweeping) { 76 if (mGoingUp) { 77 mPhaseIncrement *= mUpScaler; 78 if (mPhaseIncrement > mPhaseIncrementHigh) { 79 mGoingUp = false; 80 } 81 } else { 82 mPhaseIncrement *= mDownScaler; 83 if (mPhaseIncrement < mPhaseIncrementLow) { 84 mGoingUp = true; 85 } 86 } 87 } 88 } 89 90 double mAmplitude = 0.05; // unitless scaler 91 double mPhase = 0.0; 92 double mPhaseIncrement = 440 * M_PI * 2 / 48000; 93 double mFrameRate = 48000; 94 double mPhaseIncrementLow; 95 double mPhaseIncrementHigh; 96 double mUpScaler = 1.0; 97 double mDownScaler = 1.0; 98 bool mGoingUp = false; 99 bool mSweeping = false; 100 }; 101 102 #endif /* SINE_GENERATOR_H */ 103 104