| /* |
| * Copyright (C) 2020 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 _PLAYER_SAMPLESOURCE_ |
| #define _PLAYER_SAMPLESOURCE_ |
| |
| #include <cstdint> |
| |
| #include "DataSource.h" |
| |
| #include "SampleBuffer.h" |
| |
| namespace iolib { |
| |
| /** |
| * Defines an interface for audio data provided to a player object. |
| * Concrete examples include OneShotSampleBuffer. One could imagine a LoopingSampleBuffer. |
| * Supports stereo position via mPan member. |
| */ |
| class SampleSource: public DataSource { |
| public: |
| // Pan position of the audio in a stereo mix |
| // [left:-1.0f] <- [center: 0.0f] -> -[right: 1.0f] |
| static constexpr float PAN_HARDLEFT = -1.0f; |
| static constexpr float PAN_HARDRIGHT = 1.0f; |
| static constexpr float PAN_CENTER = 0.0f; |
| |
| SampleSource(SampleBuffer *sampleBuffer, float pan) |
| : mSampleBuffer(sampleBuffer), mCurFrameIndex(0), mIsPlaying(false) { |
| setPan(pan); |
| } |
| virtual ~SampleSource() {} |
| |
| void setPlayMode() { mCurFrameIndex = 0; mIsPlaying = true; } |
| void setStopMode() { mIsPlaying = false; mCurFrameIndex = 0; } |
| |
| bool isPlaying() { return mIsPlaying; } |
| |
| void setPan(float pan) { |
| if (pan < PAN_HARDLEFT) { |
| mPan = PAN_HARDLEFT; |
| } else if (pan > PAN_HARDRIGHT) { |
| mPan = PAN_HARDRIGHT; |
| } else { |
| mPan = pan; |
| } |
| |
| // useful information: http://www.cs.cmu.edu/~music/icm-online/readings/panlaws/ |
| mLeftGain = (mPan * 0.5) + 0.5; |
| mRightGain = 1.0 - mLeftGain; |
| } |
| |
| protected: |
| SampleBuffer *mSampleBuffer; |
| |
| int32_t mCurFrameIndex; |
| |
| bool mIsPlaying; |
| |
| // Logical pan value |
| float mPan; |
| |
| // precomputed channel gains |
| float mLeftGain; |
| float mRightGain; |
| }; |
| |
| } // namespace wavlib |
| |
| #endif //_PLAYER_SAMPLESOURCE_ |