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/**
* OpenAL cross platform audio library
* Copyright (C) 2018 by authors.
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
* Or go to http://www.gnu.org/copyleft/lgpl.html
*/
#include "config.h"
#include "backends/sdl2.h"
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <string>
#include "AL/al.h"
#include "alcmain.h"
#include "alexcpt.h"
#include "almalloc.h"
#include "alu.h"
#include "logging.h"
#include <SDL2/SDL.h>
namespace {
#ifdef _WIN32
#define DEVNAME_PREFIX "OpenAL Soft on "
#else
#define DEVNAME_PREFIX ""
#endif
constexpr ALCchar defaultDeviceName[] = DEVNAME_PREFIX "Default Device";
struct Sdl2Backend final : public BackendBase {
Sdl2Backend(ALCdevice *device) noexcept : BackendBase{device} { }
~Sdl2Backend() override;
void audioCallback(Uint8 *stream, int len) noexcept;
static void audioCallbackC(void *ptr, Uint8 *stream, int len) noexcept
{ static_cast<Sdl2Backend*>(ptr)->audioCallback(stream, len); }
void open(const ALCchar *name) override;
bool reset() override;
bool start() override;
void stop() override;
SDL_AudioDeviceID mDeviceID{0u};
ALuint mFrameSize{0};
ALuint mFrequency{0u};
DevFmtChannels mFmtChans{};
DevFmtType mFmtType{};
ALuint mUpdateSize{0u};
DEF_NEWDEL(Sdl2Backend)
};
Sdl2Backend::~Sdl2Backend()
{
if(mDeviceID)
SDL_CloseAudioDevice(mDeviceID);
mDeviceID = 0;
}
void Sdl2Backend::audioCallback(Uint8 *stream, int len) noexcept
{
const auto ulen = static_cast<unsigned int>(len);
assert((ulen % mFrameSize) == 0);
aluMixData(mDevice, stream, ulen / mFrameSize, mDevice->channelsFromFmt());
}
void Sdl2Backend::open(const ALCchar *name)
{
SDL_AudioSpec want{}, have{};
want.freq = static_cast<int>(mDevice->Frequency);
switch(mDevice->FmtType)
{
case DevFmtUByte: want.format = AUDIO_U8; break;
case DevFmtByte: want.format = AUDIO_S8; break;
case DevFmtUShort: want.format = AUDIO_U16SYS; break;
case DevFmtShort: want.format = AUDIO_S16SYS; break;
case DevFmtUInt: /* fall-through */
case DevFmtInt: want.format = AUDIO_S32SYS; break;
case DevFmtFloat: want.format = AUDIO_F32; break;
}
want.channels = (mDevice->FmtChans == DevFmtMono) ? 1 : 2;
want.samples = static_cast<Uint16>(mDevice->UpdateSize);
want.callback = &Sdl2Backend::audioCallbackC;
want.userdata = this;
/* Passing nullptr to SDL_OpenAudioDevice opens a default, which isn't
* necessarily the first in the list.
*/
if(!name || strcmp(name, defaultDeviceName) == 0)
mDeviceID = SDL_OpenAudioDevice(nullptr, SDL_FALSE, &want, &have,
SDL_AUDIO_ALLOW_ANY_CHANGE);
else
{
const size_t prefix_len = strlen(DEVNAME_PREFIX);
if(strncmp(name, DEVNAME_PREFIX, prefix_len) == 0)
mDeviceID = SDL_OpenAudioDevice(name+prefix_len, SDL_FALSE, &want, &have,
SDL_AUDIO_ALLOW_ANY_CHANGE);
else
mDeviceID = SDL_OpenAudioDevice(name, SDL_FALSE, &want, &have,
SDL_AUDIO_ALLOW_ANY_CHANGE);
}
if(mDeviceID == 0)
throw al::backend_exception{ALC_INVALID_VALUE, "%s", SDL_GetError()};
mDevice->Frequency = static_cast<ALuint>(have.freq);
if(have.channels == 1)
mDevice->FmtChans = DevFmtMono;
else if(have.channels == 2)
mDevice->FmtChans = DevFmtStereo;
else
throw al::backend_exception{ALC_INVALID_VALUE, "Unhandled SDL channel count: %d",
int{have.channels}};
switch(have.format)
{
case AUDIO_U8: mDevice->FmtType = DevFmtUByte; break;
case AUDIO_S8: mDevice->FmtType = DevFmtByte; break;
case AUDIO_U16SYS: mDevice->FmtType = DevFmtUShort; break;
case AUDIO_S16SYS: mDevice->FmtType = DevFmtShort; break;
case AUDIO_S32SYS: mDevice->FmtType = DevFmtInt; break;
case AUDIO_F32SYS: mDevice->FmtType = DevFmtFloat; break;
default:
throw al::backend_exception{ALC_INVALID_VALUE, "Unhandled SDL format: 0x%04x",
have.format};
}
mDevice->UpdateSize = have.samples;
mDevice->BufferSize = have.samples * 2; /* SDL always (tries to) use two periods. */
mFrameSize = mDevice->frameSizeFromFmt();
mFrequency = mDevice->Frequency;
mFmtChans = mDevice->FmtChans;
mFmtType = mDevice->FmtType;
mUpdateSize = mDevice->UpdateSize;
mDevice->DeviceName = name ? name : defaultDeviceName;
}
bool Sdl2Backend::reset()
{
mDevice->Frequency = mFrequency;
mDevice->FmtChans = mFmtChans;
mDevice->FmtType = mFmtType;
mDevice->UpdateSize = mUpdateSize;
mDevice->BufferSize = mUpdateSize * 2;
SetDefaultWFXChannelOrder(mDevice);
return true;
}
bool Sdl2Backend::start()
{
SDL_PauseAudioDevice(mDeviceID, 0);
return true;
}
void Sdl2Backend::stop()
{ SDL_PauseAudioDevice(mDeviceID, 1); }
} // namespace
BackendFactory &SDL2BackendFactory::getFactory()
{
static SDL2BackendFactory factory{};
return factory;
}
bool SDL2BackendFactory::init()
{ return (SDL_InitSubSystem(SDL_INIT_AUDIO) == 0); }
bool SDL2BackendFactory::querySupport(BackendType type)
{ return type == BackendType::Playback; }
std::string SDL2BackendFactory::probe(DevProbe type)
{
std::string outnames;
if(type != DevProbe::Playback)
return outnames;
int num_devices{SDL_GetNumAudioDevices(SDL_FALSE)};
/* Includes null char. */
outnames.append(defaultDeviceName, sizeof(defaultDeviceName));
for(int i{0};i < num_devices;++i)
{
std::string name{DEVNAME_PREFIX};
name += SDL_GetAudioDeviceName(i, SDL_FALSE);
if(!name.empty())
outnames.append(name.c_str(), name.length()+1);
}
return outnames;
}
BackendPtr SDL2BackendFactory::createBackend(ALCdevice *device, BackendType type)
{
if(type == BackendType::Playback)
return BackendPtr{new Sdl2Backend{device}};
return nullptr;
}
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