cocoa_s.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
/*****************************************************************************
 *                             Cocoa sound driver                            *
 * Known things left to do:                                                  *
 * - Might need to do endian checking for it to work on both ppc and x86     *
 *****************************************************************************/
 
#ifdef WITH_COCOA
 
#include "../stdafx.h"
#include "../os/macosx/macos.h"
#include "../debug.h"
#include "../driver.h"
#include "../mixer.h"
#include "cocoa_s.h"
 
#define Rect        OTTDRect
#define Point       OTTDPoint
#include <AudioUnit/AudioUnit.h>
#undef Rect
#undef Point
 
#include "../safeguards.h"
 
static FSoundDriver_Cocoa iFSoundDriver_Cocoa;
 
static AudioUnit _outputAudioUnit;
 
/* The CoreAudio callback */
static OSStatus audioCallback(void *, AudioUnitRenderActionFlags *, const AudioTimeStamp *, UInt32, UInt32, AudioBufferList *ioData)
{
  MxMixSamples(ioData->mBuffers[0].mData, ioData->mBuffers[0].mDataByteSize / 4);
 
  return noErr;
}
 
 
std::optional<std::string_view> SoundDriver_Cocoa::Start(const StringList &parm)
{
  struct AURenderCallbackStruct callback;
  AudioStreamBasicDescription requestedDesc;
 
  /* Setup a AudioStreamBasicDescription with the requested format */
  requestedDesc.mFormatID = kAudioFormatLinearPCM;
  requestedDesc.mFormatFlags = kLinearPCMFormatFlagIsPacked;
  requestedDesc.mChannelsPerFrame = 2;
  requestedDesc.mSampleRate = GetDriverParamInt(parm, "hz", 44100);
 
  requestedDesc.mBitsPerChannel = 16;
  requestedDesc.mFormatFlags |= kLinearPCMFormatFlagIsSignedInteger;
 
  if constexpr (std::endian::native == std::endian::big) {
    requestedDesc.mFormatFlags |= kLinearPCMFormatFlagIsBigEndian;
  }
 
  requestedDesc.mFramesPerPacket = 1;
  requestedDesc.mBytesPerFrame = requestedDesc.mBitsPerChannel * requestedDesc.mChannelsPerFrame / 8;
  requestedDesc.mBytesPerPacket = requestedDesc.mBytesPerFrame * requestedDesc.mFramesPerPacket;
 
  MxInitialize((uint)requestedDesc.mSampleRate);
 
  /* Locate the default output audio unit */
  AudioComponentDescription desc;
  desc.componentType = kAudioUnitType_Output;
  desc.componentSubType = kAudioUnitSubType_HALOutput;
  desc.componentManufacturer = kAudioUnitManufacturer_Apple;
  desc.componentFlags = 0;
  desc.componentFlagsMask = 0;
 
  AudioComponent comp = AudioComponentFindNext (nullptr, &desc);
  if (comp == nullptr) {
    return "cocoa_s: Failed to start CoreAudio: AudioComponentFindNext returned nullptr";
  }
 
  /* Open & initialize the default output audio unit */
  if (AudioComponentInstanceNew(comp, &_outputAudioUnit) != noErr) {
    return "cocoa_s: Failed to start CoreAudio: AudioComponentInstanceNew";
  }
 
  if (AudioUnitInitialize(_outputAudioUnit) != noErr) {
    return "cocoa_s: Failed to start CoreAudio: AudioUnitInitialize";
  }
 
  /* Set the input format of the audio unit. */
  if (AudioUnitSetProperty(_outputAudioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &requestedDesc, sizeof(requestedDesc)) != noErr) {
    return "cocoa_s: Failed to start CoreAudio: AudioUnitSetProperty (kAudioUnitProperty_StreamFormat)";
  }
 
  /* Set the audio callback */
  callback.inputProc = audioCallback;
  callback.inputProcRefCon = nullptr;
  if (AudioUnitSetProperty(_outputAudioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input, 0, &callback, sizeof(callback)) != noErr) {
    return "cocoa_s: Failed to start CoreAudio: AudioUnitSetProperty (kAudioUnitProperty_SetRenderCallback)";
  }
 
  /* Finally, start processing of the audio unit */
  if (AudioOutputUnitStart(_outputAudioUnit) != noErr) {
    return "cocoa_s: Failed to start CoreAudio: AudioOutputUnitStart";
  }
 
  /* We're running! */
  return std::nullopt;
}
 
 
void SoundDriver_Cocoa::Stop()
{
  struct AURenderCallbackStruct callback;
 
  /* stop processing the audio unit */
  if (AudioOutputUnitStop(_outputAudioUnit) != noErr) {
    Debug(driver, 0, "cocoa_s: Core_CloseAudio: AudioOutputUnitStop failed");
    return;
  }
 
  /* Remove the input callback */
  callback.inputProc = 0;
  callback.inputProcRefCon = 0;
  if (AudioUnitSetProperty(_outputAudioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input, 0, &callback, sizeof(callback)) != noErr) {
    Debug(driver, 0, "cocoa_s: Core_CloseAudio: AudioUnitSetProperty (kAudioUnitProperty_SetRenderCallback) failed");
    return;
  }
 
  if (AudioComponentInstanceDispose(_outputAudioUnit) != noErr) {
    Debug(driver, 0, "cocoa_s: Core_CloseAudio: AudioComponentInstanceDispose failed");
    return;
  }
}
 
#endif /* WITH_COCOA */