ALSA: Add experimental MIDI support

Fix incorrect SendMessageToAllChannels resulting in not all channels being stopped.

CMakeLists.txt

@@ -669,10 +669,32 @@ if(${PLAYER_AUDIO_BACKEND} MATCHES "^(SDL2|libretro)$")
 	set(PLAYER_HAS_AUDIO ON)
 	target_compile_definitions(${PROJECT_NAME} PUBLIC SUPPORT_AUDIO=1)
 
-	if (WIN32 OR APPLE)
-		option(PLAYER_WITH_NATIVE_MIDI "Play MIDI audio using the API of the operating system." ON)
-		if(PLAYER_WITH_NATIVE_MIDI)
-			target_compile_definitions(${PROJECT_NAME} PUBLIC HAVE_NATIVE_MIDI=1)
+	if(${PLAYER_AUDIO_BACKEND} STREQUAL "libretro")
+	elseif(WIN32 OR APPLE)
+		set(SUPPORT_NATIVE_MIDI ON)
+	elseif(UNIX)
+		if(${CMAKE_VERSION} VERSION_GREATER_EQUAL 3.12)
+			find_package(ALSA)
+			if(ALSA_FOUND)
+				set(SUPPORT_NATIVE_MIDI ON)
+			endif()
+		endif()
+	endif()
+
+	CMAKE_DEPENDENT_OPTION(PLAYER_WITH_NATIVE_MIDI "Play MIDI audio using the API of the operating system" ON "SUPPORT_NATIVE_MIDI" OFF)
+	if(PLAYER_WITH_NATIVE_MIDI)
+		target_compile_definitions(${PROJECT_NAME} PUBLIC HAVE_NATIVE_MIDI=1)
+		if(ALSA_FOUND)
+			target_compile_definitions(${PROJECT_NAME} PUBLIC HAVE_ALSA=1)
+			target_sources(${PROJECT_NAME} PRIVATE
+				src/platform/linux/midiout_device_alsa.cpp
+				src/platform/linux/midiout_device_alsa.h
+			)
+			target_link_libraries(${PROJECT_NAME} ALSA::ALSA)
+			find_package(Threads)
+			if(Threads_FOUND)
+				target_link_libraries(${PROJECT_NAME} Threads::Threads)
+			endif()
 		endif()
 	endif()
 

Makefile.am

@@ -22,8 +22,8 @@ libeasyrpg_player_a_SOURCES = \
 	src/audio_decoder.h \
 	src/audio_decoder_base.cpp \
 	src/audio_decoder_base.h \
-	src/audio_decoder_midi.cpp
-	src/audio_decoder_midi.h
+	src/audio_decoder_midi.cpp \
+	src/audio_decoder_midi.h \
 	src/audio_generic.cpp \
 	src/audio_generic.h \
 	src/audio_generic_midiout.cpp \
@@ -436,10 +436,18 @@ libeasyrpg_player_a_SOURCES += \
 	src/dr_wav.h
 endif
 
+if HAVE_ALSA
+libeasyrpg_player_a_SOURCES += \
+	src/platform/linux/midiout_device_alsa.cpp \
+	src/platform/linux/midiout_device_alsa.h
+endif
+
 if MACOS
 libeasyrpg_player_a_SOURCES += \
 	src/platform/macos/utils.h \
-	src/platform/macos/utils.mm
+	src/platform/macos/utils.mm \
+	src/platform/macos/midiout_device_coreaudio.cpp \
+	src/platform/macos/midiout_device_coreaudio.h
 endif
 
 # These are only taken in by the legacy homebrew Makefiles
@@ -476,6 +484,8 @@ EXTRA_DIST += \
 	src/platform/wii/wii_input_buttons.cpp \
 	src/platform/opendingux/opendingux_input_buttons.cpp \
 	src/platform/psp/psp_input_buttons.cpp \
+	src/platform/windows/midiout_device_win32.cpp \
+	src/platform/windows/midiout_device_win32.h \
 	src/platform/windows/utils.cpp \
 	src/platform/windows/utils.h
 
@@ -498,7 +508,9 @@ libeasyrpg_player_a_CXXFLAGS = \
 	$(LIBXMP_CFLAGS) \
 	$(LIBSPEEXDSP_CFLAGS) \
 	$(FLUIDSYNTH_CFLAGS) \
-	$(FLUIDLITE_CFLAGS)
+	$(FLUIDLITE_CFLAGS) \
+	$(ALSA_CFLAGS) \
+	$(PTHREAD_CFLAGS)
 
 libeasyrpg_player_a_OBJCXXFLAGS = $(libeasyrpg_player_a_CXXFLAGS)
 
@@ -521,7 +533,9 @@ easyrpg_player_LDADD = libeasyrpg-player.a \
 	$(LIBXMP_LIBS) \
 	$(LIBSPEEXDSP_LIBS) \
 	$(FLUIDSYNTH_LIBS) \
-	$(FLUIDLITE_LIBS)
+	$(FLUIDLITE_LIBS) \
+	$(ALSA_LIBS) \
+	$(PTHREAD_LIBS)
 
 if MACOS
 easyrpg_player_LDFLAGS = -framework Foundation