initial attempt at porting to SDL3

include/soloud.h

@@ -194,6 +194,7 @@ namespace SoLoud
 			MINIAUDIO,
 			NOSOUND,
 			NULLDRIVER,
+			SDL3,
 			BACKEND_MAX,
 		};
 

include/soloud_c.h

@@ -55,7 +55,8 @@ enum SOLOUD_ENUMS
 	SOLOUD_MINIAUDIO = 14,
 	SOLOUD_NOSOUND = 15,
 	SOLOUD_NULLDRIVER = 16,
-	SOLOUD_BACKEND_MAX = 17,
+	SOLOUD_SDL3 = 17,
+	SOLOUD_BACKEND_MAX = 18,
 	SOLOUD_CLIP_ROUNDOFF = 1,
 	SOLOUD_ENABLE_VISUALIZATION = 2,
 	SOLOUD_LEFT_HANDED_3D = 4,

include/soloud_internal.h

@@ -41,6 +41,9 @@ namespace SoLoud
 	// SDL2 "non-dynamic" back-end initialization call
 	result sdl2static_init(SoLoud::Soloud *aSoloud, unsigned int aFlags = Soloud::CLIP_ROUNDOFF, unsigned int aSamplerate = 44100, unsigned int aBuffer = 2048, unsigned int aChannels = 2);
 
+	// SDL3 "non-dynamic" back-end initialization call
+	result sdl3static_init(SoLoud::Soloud *aSoloud, unsigned int aFlags = Soloud::CLIP_ROUNDOFF, unsigned int aSamplerate = 44100, unsigned int aBuffer = 2048, unsigned int aChannels = 2);
+
 	// OpenAL back-end initialization call
 	result openal_init(SoLoud::Soloud *aSoloud, unsigned int aFlags = Soloud::CLIP_ROUNDOFF, unsigned int aSamplerate = 44100, unsigned int aBuffer = 2048, unsigned int aChannels = 2);
 

src/backend/sdl3_static/soloud_sdl3_static.cpp

@@ -0,0 +1,101 @@
+/*
+SoLoud audio engine
+Copyright (c) 2013-2015 Jari Komppa
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+   1. The origin of this software must not be misrepresented; you must not
+   claim that you wrote the original software. If you use this software
+   in a product, an acknowledgment in the product documentation would be
+   appreciated but is not required.
+
+   2. Altered source versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.
+
+   3. This notice may not be removed or altered from any source
+   distribution.
+*/
+#include <stdlib.h>
+
+#include "soloud.h"
+
+#if !defined(WITH_SDL3_STATIC)
+
+namespace SoLoud
+{
+	result sdl3static_init(SoLoud::Soloud *aSoloud, unsigned int aFlags, unsigned int aSamplerate, unsigned int aBuffer)
+	{
+		return NOT_IMPLEMENTED;
+	}
+}
+
+#else
+
+#include <SDL3/SDL.h>
+#include <math.h>
+
+namespace SoLoud
+{
+	static unsigned int gSamples;
+	static SDL_AudioSpec gActiveAudioSpec;
+	static SDL_AudioStream *gAudioStream;
+
+	void soloud_sdl3static_audiomixer(void *userdata, SDL_AudioStream* stream, int additional_amount, int total_amount)
+	{
+		if (additional_amount > 0) {
+			Uint8 *data = SDL_stack_alloc(Uint8, additional_amount);
+			if (data) {
+				SoLoud::Soloud *soloud = (SoLoud::Soloud *)userdata;
+
+				int samples = additional_amount / (gActiveAudioSpec.channels * sizeof(float));
+				// TODO: in practice it seems like it's safe to ignore the case where samples > gSamples
+				// because the scratch buffers are always so big, but is this really safe?
+				soloud->mix((float*)data, samples);
+
+				SDL_PutAudioStreamData(stream, data, additional_amount);
+				SDL_stack_free(data);
+			}
+		}
+	}
+
+	static void soloud_sdl3static_deinit(SoLoud::Soloud *aSoloud)
+	{
+		SDL_DestroyAudioStream(gAudioStream);
+	}
+
+	result sdl3static_init(SoLoud::Soloud *aSoloud, unsigned int aFlags, unsigned int aSamplerate, unsigned int aBuffer, unsigned int aChannels)
+	{
+		if (!SDL_WasInit(SDL_INIT_AUDIO))
+		{
+			if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0)
+			{
+				return UNKNOWN_ERROR;
+			}
+		}
+
+		gSamples = aBuffer;
+
+		gActiveAudioSpec = { SDL_AUDIO_F32LE, (int)aChannels, (int)aSamplerate };
+
+		gAudioStream = SDL_OpenAudioDeviceStream(SDL_AUDIO_DEVICE_DEFAULT_OUTPUT, &gActiveAudioSpec, soloud_sdl3static_audiomixer, (void*)aSoloud);
+		if (!gAudioStream)
+		{
+			return UNKNOWN_ERROR;
+		}
+
+		aSoloud->postinit_internal(gActiveAudioSpec.freq, gSamples, aFlags, gActiveAudioSpec.channels);
+
+		aSoloud->mBackendCleanupFunc = soloud_sdl3static_deinit;
+
+		SDL_ResumeAudioDevice(SDL_GetAudioStreamDevice(gAudioStream));
+		aSoloud->mBackendString = "SDL3 (static)";
+		return 0;
+	}
+};
+#endif

src/core/soloud.cpp

@@ -46,7 +46,7 @@ freely, subject to the following restrictions:
    !defined(WITH_WASAPI) && !defined(WITH_OSS) && !defined(WITH_SDL1_STATIC) && \
    !defined(WITH_SDL2_STATIC) && !defined(WITH_ALSA) && !defined(WITH_OPENSLES) && \
    !defined(WITH_NULL) && !defined(WITH_COREAUDIO) && !defined(WITH_VITA_HOMEBREW) &&\
-   !defined(WITH_JACK) && !defined(WITH_NOSOUND) && !defined(WITH_MINIAUDIO)
+   !defined(WITH_JACK) && !defined(WITH_NOSOUND) && !defined(WITH_MINIAUDIO) && !defined(WITH_SDL3_STATIC)
 #error It appears you haven't enabled any of the back-ends. Please #define one or more of the WITH_ defines (or use premake) '
 #endif
 
@@ -261,6 +261,25 @@ namespace SoLoud
 		}
 #endif
 
+#if defined(WITH_SDL3_STATIC)
+		if (!inited &&
+			(aBackend == Soloud::SDL3 ||
+			aBackend == Soloud::AUTO))
+		{
+			if (aBufferSize == Soloud::AUTO) buffersize = 2048;
+
+			int ret = sdl3static_init(this, aFlags, samplerate, buffersize, aChannels);
+			if (ret == 0)
+			{
+				inited = 1;
+				mBackendID = Soloud::SDL3;
+			}
+
+			if (ret != 0 && aBackend != Soloud::AUTO)
+				return ret;
+		}
+#endif
+
 #if defined(WITH_SDL2)
 		if (!inited &&
 			(aBackend == Soloud::SDL2 ||