godot/platform/osx/audio_driver_osx.cpp

/*************************************************************************/
/*  audio_driver_osx.cpp                                                 */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                 */
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#ifdef OSX_ENABLED

#include "audio_driver_osx.h"

Error AudioDriverOSX::init() {

	active = false;
	channels = 2;

	AudioStreamBasicDescription strdesc;
	strdesc.mFormatID = kAudioFormatLinearPCM;
	strdesc.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger | kLinearPCMFormatFlagIsPacked;
	strdesc.mChannelsPerFrame = channels;
	strdesc.mSampleRate = 44100;
	strdesc.mFramesPerPacket = 1;
	strdesc.mBitsPerChannel = 16;
	strdesc.mBytesPerFrame =
		strdesc.mBitsPerChannel * strdesc.mChannelsPerFrame / 8;
	strdesc.mBytesPerPacket =
		strdesc.mBytesPerFrame * strdesc.mFramesPerPacket;

	OSStatus result = noErr;
	AURenderCallbackStruct callback;
	AudioComponentDescription desc;
	AudioComponent comp = NULL;
	const AudioUnitElement output_bus = 0;
	const AudioUnitElement bus = output_bus;
	const AudioUnitScope scope = kAudioUnitScope_Input;

	zeromem(&desc, sizeof(desc));
	desc.componentType = kAudioUnitType_Output;
	desc.componentSubType = 0;  /* !!! FIXME: ? */
	comp = AudioComponentFindNext(NULL, &desc);
	desc.componentManufacturer = kAudioUnitManufacturer_Apple;

	result = AudioComponentInstanceNew(comp, &audio_unit);
	ERR_FAIL_COND_V(result != noErr, FAILED);
	ERR_FAIL_COND_V(comp == NULL, FAILED);

	result = AudioUnitSetProperty(audio_unit,
								  kAudioUnitProperty_StreamFormat,
								  scope, bus, &strdesc, sizeof(strdesc));
	ERR_FAIL_COND_V(result != noErr, FAILED);

	zeromem(&callback, sizeof(AURenderCallbackStruct));
	callback.inputProc = &AudioDriverOSX::output_callback;
	callback.inputProcRefCon = this;
	result = AudioUnitSetProperty(audio_unit,
								  kAudioUnitProperty_SetRenderCallback,
								  scope, bus, &callback, sizeof(callback));
	ERR_FAIL_COND_V(result != noErr, FAILED);

	result = AudioUnitInitialize(audio_unit);
	ERR_FAIL_COND_V(result != noErr, FAILED);

	result = AudioOutputUnitStart(audio_unit);
	ERR_FAIL_COND_V(result != noErr, FAILED);

	const int samples = 1024;
	samples_in = memnew_arr(int32_t, samples); // whatever
	buffer_frames = samples / channels;

	return OK;
};

OSStatus AudioDriverOSX::output_callback(void *inRefCon,
			   AudioUnitRenderActionFlags * ioActionFlags,
			   const AudioTimeStamp * inTimeStamp,
			   UInt32 inBusNumber, UInt32 inNumberFrames,
			   AudioBufferList * ioData) {


	AudioBuffer *abuf;
	AudioDriverOSX* ad = (AudioDriverOSX*)inRefCon;

	if (!ad->active) {
		for (unsigned int i = 0; i < ioData->mNumberBuffers; i++) {
			abuf = &ioData->mBuffers[i];
			zeromem(abuf->mData, abuf->mDataByteSize);
		};
		return 0;
	};

	int frames_left;

	for (unsigned int i = 0; i < ioData->mNumberBuffers; i++) {

		abuf = &ioData->mBuffers[i];
		frames_left = inNumberFrames;
		int16_t* out = (int16_t*)abuf->mData;

		while (frames_left) {

			int frames = MIN(frames_left, ad->buffer_frames);
			ad->lock();
			ad->audio_server_process(frames, ad->samples_in);
			ad->unlock();

			for(int i = 0; i < frames * ad->channels; i++) {

				out[i] = ad->samples_in[i]>>16;
			}

			frames_left -= frames;
			out += frames * ad->channels;
		};
	};

	return 0;
};

void AudioDriverOSX::start() {
	active = true;
};

int AudioDriverOSX::get_mix_rate() const {
	return 44100;
};

AudioDriverSW::OutputFormat AudioDriverOSX::get_output_format() const {
	return OUTPUT_STEREO;
};

void AudioDriverOSX::lock() {};
void AudioDriverOSX::unlock() {};

void AudioDriverOSX::finish() {

	memdelete_arr(samples_in);
};

#endif