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 WAVETABLEOSCILLATOR_H_ 18 #define WAVETABLEOSCILLATOR_H_ 19 20 #include "PeriodicAudioSource.h" 21 22 namespace ndkaudio { 23 24 /* 25 * The assumption here is that the provided wave table contains 1 cycle of the wave 26 * and that the first and last samples are the same. 27 */ 28 class WaveTableOscillator : public PeriodicAudioSource { 29 public: 30 WaveTableOscillator(int numChannels, float* waveTable, int waveTableSize); 31 32 void setWaveTable(float* waveTable, int waveTableSize); 33 34 int getData(long time, float* outBuff, int numFrames, int outChans); 35 36 private: 37 float* waveTable_; 38 int waveTableSize_; 39 40 // 'nominal' frequency (i.e. how many times we step through the 41 // 1-cycle wave table in a second 42 float fN_; 43 44 // current pointer into the wave table 45 float srcPhase_; 46 47 // profiling 48 long prevFillTime_; 49 }; 50 51 } // namespace ndkaudio 52 53 #endif /* WAVETABLEOSCILLATOR_H_ */ 54
