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Convert the alloopback example to use SDL3
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@kcat
kcat committed Dec 6, 2024
1 parent 020a3e4 commit 1b8a0bc
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Showing 2 changed files with 79 additions and 55 deletions.
15 changes: 10 additions & 5 deletions CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,7 @@ include(CMakePackageConfigHelpers)
include(GNUInstallDirs)

find_package(PkgConfig)
find_package(SDL3 QUIET)
find_package(SDL2 QUIET)

add_subdirectory(fmt-11.0.2 EXCLUDE_FROM_ALL)
Expand Down Expand Up @@ -1816,17 +1817,21 @@ if(ALSOFT_EXAMPLES)
message(STATUS "Building SndFile example programs")
endif()

if(SDL2_FOUND)
# Can't safely use SDL3 and SDL2 together
if(SDL3_FOUND AND NOT HAVE_SDL2)
message(STATUS "Building SDL3 example programs")

add_executable(alloopback examples/alloopback.c)
target_link_libraries(alloopback
PRIVATE ${LINKER_FLAGS} SDL2::SDL2 alsoft.excommon ${MATH_LIB})
PRIVATE ${LINKER_FLAGS} SDL3::SDL3 alsoft.excommon ${MATH_LIB})
set_target_properties(alloopback PROPERTIES ${ALSOFT_STD_VERSION_PROPS})

if(ALSOFT_INSTALL_EXAMPLES)
set(EXTRA_INSTALLS ${EXTRA_INSTALLS} alloopback)
endif()

message(STATUS "Building SDL example programs")
endif()
if(SDL2_FOUND)
message(STATUS "Building SDL2 example programs")

set(FFVER_OK FALSE)
if(FFMPEG_FOUND)
Expand Down Expand Up @@ -1862,7 +1867,7 @@ if(ALSOFT_EXAMPLES)
if(ALSOFT_INSTALL_EXAMPLES)
set(EXTRA_INSTALLS ${EXTRA_INSTALLS} alffplay)
endif()
message(STATUS "Building SDL+FFmpeg example programs")
message(STATUS "Building SDL2+FFmpeg example programs")
endif()
endif()
message(STATUS "")
Expand Down
119 changes: 69 additions & 50 deletions examples/alloopback.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,27 +29,21 @@
#include <assert.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define SDL_MAIN_HANDLED
#include "SDL.h"
#include "SDL_audio.h"
#include "SDL_error.h"
#include "SDL_stdinc.h"
#include "SDL3/SDL_audio.h"
#include "SDL3/SDL_error.h"
#include "SDL3/SDL_main.h"
#include "SDL3/SDL_stdinc.h"

#include "AL/al.h"
#include "AL/alc.h"
#include "AL/alext.h"

#include "common/alhelpers.h"

#ifndef SDL_AUDIO_MASK_BITSIZE
#define SDL_AUDIO_MASK_BITSIZE (0xFF)
#endif
#ifndef SDL_AUDIO_BITSIZE
#define SDL_AUDIO_BITSIZE(x) (x & SDL_AUDIO_MASK_BITSIZE)
#endif

#ifndef M_PI
#define M_PI (3.14159265358979323846)
#endif
Expand All @@ -59,17 +53,35 @@ typedef struct {
ALCcontext *Context;

ALCsizei FrameSize;
void *Buffer;
int BufferSize;
} PlaybackInfo;

static LPALCLOOPBACKOPENDEVICESOFT alcLoopbackOpenDeviceSOFT;
static LPALCISRENDERFORMATSUPPORTEDSOFT alcIsRenderFormatSupportedSOFT;
static LPALCRENDERSAMPLESSOFT alcRenderSamplesSOFT;


void SDLCALL RenderSDLSamples(void *userdata, Uint8 *stream, int len)
void SDLCALL RenderSDLSamples(void *userdata, SDL_AudioStream *stream, int additional_amount,
int total_amount)
{
PlaybackInfo *playback = (PlaybackInfo*)userdata;
alcRenderSamplesSOFT(playback->Device, stream, len/playback->FrameSize);

if(additional_amount < 0)
additional_amount = total_amount;
if(additional_amount <= 0)
return;

if(additional_amount > playback->BufferSize)
{
free(playback->Buffer);
playback->Buffer = malloc((unsigned int)additional_amount);
playback->BufferSize = additional_amount;
}
alcRenderSamplesSOFT(playback->Device, playback->Buffer,
additional_amount/playback->FrameSize);

SDL_PutAudioStreamData(stream, playback->Buffer, additional_amount);
}


Expand Down Expand Up @@ -135,8 +147,9 @@ static ALuint CreateSineWave(void)

int main(int argc, char *argv[])
{
PlaybackInfo playback = { NULL, NULL, 0 };
SDL_AudioSpec desired, obtained;
PlaybackInfo playback = { NULL, NULL, 0, NULL, 0 };
SDL_AudioStream *stream = NULL;
SDL_AudioSpec obtained;
ALuint source, buffer;
ALCint attrs[16];
ALenum state;
Expand All @@ -159,25 +172,25 @@ int main(int argc, char *argv[])
LOAD_PROC(LPALCRENDERSAMPLESSOFT, alcRenderSamplesSOFT);
#undef LOAD_PROC

if(SDL_Init(SDL_INIT_AUDIO) == -1)
if(!SDL_Init(SDL_INIT_AUDIO))
{
fprintf(stderr, "Failed to init SDL audio: %s\n", SDL_GetError());
return 1;
}

/* Set up SDL audio with our requested format and callback. */
desired.channels = 2;
desired.format = AUDIO_S16SYS;
desired.freq = 44100;
desired.padding = 0;
desired.samples = 4096;
desired.callback = RenderSDLSamples;
desired.userdata = &playback;
if(SDL_OpenAudio(&desired, &obtained) != 0)
/* Set up SDL audio with our callback, and get the stream format. */
stream = SDL_OpenAudioDeviceStream(SDL_AUDIO_DEVICE_DEFAULT_PLAYBACK, NULL, RenderSDLSamples,
&playback);
if(!stream)
{
SDL_Quit();
fprintf(stderr, "Failed to open SDL audio: %s\n", SDL_GetError());
return 1;
goto error;
}

if(!SDL_GetAudioStreamFormat(stream, NULL, &obtained))
{
fprintf(stderr, "Failed to query SDL audio format: %s\n", SDL_GetError());
goto error;
}

/* Set up our OpenAL attributes based on what we got from SDL. */
Expand All @@ -186,24 +199,30 @@ int main(int argc, char *argv[])
attrs[1] = ALC_MONO_SOFT;
else if(obtained.channels == 2)
attrs[1] = ALC_STEREO_SOFT;
else if(obtained.channels == 4)
attrs[1] = ALC_QUAD_SOFT;
else if(obtained.channels == 6)
attrs[1] = ALC_5POINT1_SOFT;
else if(obtained.channels == 7)
attrs[1] = ALC_6POINT1_SOFT;
else if(obtained.channels == 8)
attrs[1] = ALC_7POINT1_SOFT;
else
{
fprintf(stderr, "Unhandled SDL channel count: %d\n", obtained.channels);
goto error;
}

attrs[2] = ALC_FORMAT_TYPE_SOFT;
if(obtained.format == AUDIO_U8)
if(obtained.format == SDL_AUDIO_U8)
attrs[3] = ALC_UNSIGNED_BYTE_SOFT;
else if(obtained.format == AUDIO_S8)
else if(obtained.format == SDL_AUDIO_S8)
attrs[3] = ALC_BYTE_SOFT;
else if(obtained.format == AUDIO_U16SYS)
attrs[3] = ALC_UNSIGNED_SHORT_SOFT;
else if(obtained.format == AUDIO_S16SYS)
else if(obtained.format == SDL_AUDIO_S16)
attrs[3] = ALC_SHORT_SOFT;
else if(obtained.format == AUDIO_S32SYS)
else if(obtained.format == SDL_AUDIO_S32)
attrs[3] = ALC_INT_SOFT;
else if(obtained.format == AUDIO_F32SYS)
else if(obtained.format == SDL_AUDIO_F32)
attrs[3] = ALC_FLOAT_SOFT;
else
{
Expand All @@ -216,7 +235,7 @@ int main(int argc, char *argv[])

attrs[6] = 0; /* end of list */

playback.FrameSize = obtained.channels * SDL_AUDIO_BITSIZE(obtained.format) / 8;
playback.FrameSize = obtained.channels * (int)SDL_AUDIO_BITSIZE(obtained.format) / 8;

/* Initialize OpenAL loopback device, using our format attributes. */
playback.Device = alcLoopbackOpenDeviceSOFT(NULL);
Expand All @@ -229,7 +248,7 @@ int main(int argc, char *argv[])
if(alcIsRenderFormatSupportedSOFT(playback.Device, attrs[5], attrs[1], attrs[3]) == ALC_FALSE)
{
fprintf(stderr, "Render format not supported: %s, %s, %dhz\n",
ChannelsName(attrs[1]), TypeName(attrs[3]), attrs[5]);
ChannelsName(attrs[1]), TypeName(attrs[3]), attrs[5]);
goto error;
}
playback.Context = alcCreateContext(playback.Device, attrs);
Expand All @@ -239,20 +258,18 @@ int main(int argc, char *argv[])
goto error;
}

printf("Got render format from SDL stream: %s, %s, %dhz\n", ChannelsName(attrs[1]),
TypeName(attrs[3]), attrs[5]);

/* Start SDL playing. Our callback (thus alcRenderSamplesSOFT) will now
* start being called regularly to update the AL playback state. */
SDL_PauseAudio(0);
* start being called regularly to update the AL playback state.
*/
SDL_ResumeAudioStreamDevice(stream);

/* Load the sound into a buffer. */
buffer = CreateSineWave();
if(!buffer)
{
SDL_CloseAudio();
alcDestroyContext(playback.Context);
alcCloseDevice(playback.Device);
SDL_Quit();
return 1;
}
goto error;

/* Create the source to play the sound with. */
source = 0;
Expand All @@ -272,23 +289,25 @@ int main(int argc, char *argv[])
alDeleteBuffers(1, &buffer);

/* Stop SDL playing. */
SDL_PauseAudio(1);
SDL_PauseAudioStreamDevice(stream);

/* Close up OpenAL and SDL. */
SDL_CloseAudio();
SDL_DestroyAudioStream(stream);
alcDestroyContext(playback.Context);
alcCloseDevice(playback.Device);
SDL_Quit();

SDL_QuitSubSystem(SDL_INIT_AUDIO);

return 0;

error:
SDL_CloseAudio();
if(stream)
SDL_DestroyAudioStream(stream);
if(playback.Context)
alcDestroyContext(playback.Context);
if(playback.Device)
alcCloseDevice(playback.Device);
SDL_Quit();
SDL_QuitSubSystem(SDL_INIT_AUDIO);

return 1;
}

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