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#include "audio.h"
#ifdef HAVE_XAUDIO2
#include <xaudio2.h>
#include <math.h>
struct AudioContext
{
IXAudio2 *xaudio2;
IXAudio2MasteringVoice *mastering_voice;
};
struct AudioVoice
{
AudioContext *context;
IXAudio2SourceVoice *voice;
};
struct AudioFilter
{
AudioContext *context;
XAUDIO2_FILTER_PARAMETERS params;
};
void xaudio_destroy_context(AudioContext *p_context)
{
p_context->mastering_voice->DestroyVoice();
p_context->xaudio2->Release();
delete p_context;
}
AudioVoice *xaudio_create_voice(AudioContext *p_context, float *p_buffer, size_t p_buffer_size, int p_sample_rate, int p_num_channels)
{
// create a source voice
WAVEFORMATEX waveFormat;
waveFormat.wFormatTag = WAVE_FORMAT_IEEE_FLOAT;
waveFormat.nChannels = p_num_channels;
waveFormat.nSamplesPerSec = p_sample_rate;
waveFormat.nBlockAlign = p_num_channels * 4;
waveFormat.nAvgBytesPerSec = waveFormat.nSamplesPerSec * waveFormat.nBlockAlign;
waveFormat.wBitsPerSample = 32;
waveFormat.cbSize = 0;
IXAudio2SourceVoice *voice;
XAUDIO2_SEND_DESCRIPTOR send;
XAUDIO2_VOICE_SENDS sends;
sends.SendCount = 1;
sends.pSends = &send;
send.Flags = XAUDIO2_SEND_USEFILTER;
send.pOutputVoice = p_context->mastering_voice;
HRESULT hr = p_context->xaudio2->CreateSourceVoice(&voice, &waveFormat, XAUDIO2_VOICE_USEFILTER, XAUDIO2_DEFAULT_FREQ_RATIO, NULL, &sends);
if (FAILED(hr)) {
return NULL;
}
voice->SetVolume(0.0f);
// submit the array
XAUDIO2_BUFFER buffer = { 0 };
buffer.AudioBytes = 4 * p_buffer_size * p_num_channels;
buffer.pAudioData = (byte *)p_buffer;
buffer.Flags = XAUDIO2_END_OF_STREAM;
buffer.PlayBegin = 0;
buffer.PlayLength = 0;
buffer.LoopBegin = 0;
buffer.LoopLength = 0;
buffer.LoopCount = XAUDIO2_LOOP_INFINITE;
hr = voice->SubmitSourceBuffer(&buffer);
if (FAILED(hr)) {
return NULL;
}
// start the voice playing
voice->Start();
// return a voice struct
AudioVoice *result = new AudioVoice();
result->context = p_context;
result->voice = voice;
return result;
}
void xaudio_voice_destroy(AudioVoice *p_voice)
{
}
void xaudio_voice_set_volume(AudioVoice *p_voice, float p_volume)
{
p_voice->voice->SetVolume(p_volume);
}
void xaudio_voice_set_frequency(AudioVoice *p_voice, float p_frequency)
{
p_voice->voice->SetFrequencyRatio(p_frequency);
}
AudioFilter *xaudio_create_filter(AudioContext *p_context)
{
AudioFilter *filter = new AudioFilter();
filter->context = p_context;
return filter;
}
void xaudio_filter_update(AudioFilter *p_filter, int p_type, float p_cutoff_frequency, float p_q)
{
if (p_type != -1)
{
p_filter->params.Type = XAUDIO2_FILTER_TYPE(p_type);
p_filter->params.Frequency = (float) (2 * sin(PI * p_cutoff_frequency / 44100));
p_filter->params.OneOverQ = (float)(1.0 / p_q);
}
else
{
// documentation of XAUDIO2_FILTER_PARAMETERS:
// Setting XAUDIO2_FILTER_PARAMETERS with the following values is acoustically equivalent to the filter being fully bypassed.
p_filter->params.Type = LowPassFilter;
p_filter->params.Frequency = 1.0f;
p_filter->params.OneOverQ = 1.0f;
}
}
void xaudio_filter_apply(AudioFilter *p_filter, AudioVoice *p_voice)
{
p_voice->voice->SetFilterParameters(&p_filter->params, XAUDIO2_COMMIT_ALL);
}
void xaudio_output_filter_apply(AudioFilter *p_filter, AudioVoice *p_voice)
{
p_voice->voice->SetOutputFilterParameters(p_voice->context->mastering_voice, &p_filter->params, XAUDIO2_COMMIT_ALL);
}
AudioContext *xaudio_create_context()
{
// setup function pointers
audio_destroy_context = xaudio_destroy_context;
audio_create_voice = xaudio_create_voice;
audio_voice_destroy = xaudio_voice_destroy;
audio_voice_set_volume = xaudio_voice_set_volume;
audio_voice_set_frequency = xaudio_voice_set_frequency;
audio_create_filter = xaudio_create_filter;
audio_filter_update = xaudio_filter_update;
audio_filter_apply = xaudio_filter_apply;
audio_output_filter_apply = xaudio_output_filter_apply;
// create XAudio object
IXAudio2 *xaudio2;
HRESULT hr = XAudio2Create(&xaudio2);
if (FAILED(hr))
return NULL;
// create a mastering voice
IXAudio2MasteringVoice *mastering_voice;
hr = xaudio2->CreateMasteringVoice(&mastering_voice);
if (FAILED(hr))
return NULL;
// return a context object
AudioContext *context = new AudioContext();
context->xaudio2 = xaudio2;
context->mastering_voice = mastering_voice;
return context;
}
#endif // HAVE_XAUDIO2
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