isle-portable/3rdparty/sdl3-shim/SDL3/SDL_audio.h
2025-10-18 16:40:03 -04:00

102 lines
2.9 KiB
C++

#pragma once
#include "SDL.h"
#include <map>
#include <mutex>
// https://wiki.libsdl.org/SDL3/README-migration#sdl_audioh
#define SDL_DestroyAudioStream SDL_FreeAudioStream
#define SDL_AUDIO_F32 AUDIO_F32SYS
#define SDL_AUDIO_DEVICE_DEFAULT_PLAYBACK NULL
typedef void SDL_AudioStreamCallback(void *userdata, SDL_AudioStream *stream, int additional_amount, int total_amount);
struct ShimAudioCtx {
SDL_AudioStream* stream;
SDL_AudioStreamCallback* callback;
void *userdata;
SDL_AudioSpec obtained;
};
static std::map<SDL_AudioDeviceID, ShimAudioCtx> g_audioCtxs;
static SDL_mutex *g_audioMutex = NULL;
static void SDLCALL shim_audio_callback(void *userdata, Uint8 *stream, int len) {
SDL_AudioDeviceID devid = reinterpret_cast<uintptr_t>(userdata);
SDL_LockMutex(g_audioMutex);
const auto it = g_audioCtxs.find(devid);
if (it == g_audioCtxs.end()) {
SDL_UnlockMutex(g_audioMutex);
SDL_memset(stream, 0, len);
return;
}
ShimAudioCtx &ctx = it->second;
SDL_UnlockMutex(g_audioMutex);
// How many sample frames the device is asking for
const int frame_size = (SDL_AUDIO_BITSIZE(ctx.obtained.format) / 8) * ctx.obtained.channels;
const int needed_frames = len / frame_size;
int total = (SDL_AudioStreamAvailable(ctx.stream) / frame_size) + needed_frames;
// SDL3 callback pushes more into the stream
ctx.callback(ctx.userdata, ctx.stream, needed_frames, total);
int got = SDL_AudioStreamGet(ctx.stream, stream, len);
if (got < len) {
SDL_memset(stream + got, 0, len - got);
}
}
#define SDL_ResumeAudioDevice(device) SDL_PauseAudioDevice(device, 0)
#define SDL_PutAudioStreamData(...) (SDL_AudioStreamPut(__VA_ARGS__) == 0)
inline SDL_AudioDeviceID SDL_GetAudioStreamDevice(SDL_AudioStream* stream)
{
SDL_LockMutex(g_audioMutex);
const auto it = g_audioCtxs.find(reinterpret_cast<uintptr_t>(stream));
if (it == g_audioCtxs.end()) {
return 0;
}
return it->first;
}
inline SDL_AudioStream * SDL_OpenAudioDeviceStream(const char* devid, const SDL_AudioSpec* desired, SDL_AudioStreamCallback callback, void* userdata)
{
SDL_AudioSpec obtained{};
SDL_AudioSpec desired2 = *desired;
desired2.callback = shim_audio_callback;
desired2.userdata = reinterpret_cast<void*>(static_cast<uintptr_t>(0));
SDL_AudioDeviceID device = SDL_OpenAudioDevice(devid, 0, &desired2, &obtained, 0);
SDL_AudioStream* stream = SDL_NewAudioStream(
desired->format, desired->channels, desired->freq,
obtained.format, obtained.channels, obtained.freq
);
if (!stream) {
SDL_CloseAudioDevice(device);
return nullptr;
}
{
SDL_LockMutex(g_audioMutex);
ShimAudioCtx ctx;
ctx.stream = stream;
ctx.callback = callback;
ctx.userdata = userdata;
ctx.obtained = obtained;
g_audioCtxs[device] = ctx;
SDL_UnlockMutex(g_audioMutex);
}
SDL_LockAudioDevice(device);
desired2.userdata = reinterpret_cast<void*>(static_cast<uintptr_t>(device));
SDL_UnlockAudioDevice(device);
return stream;
}