SDL_Audio support. (#340)

* SDL_Audio support.

Replace RtAudio with SDL2-Audio system.  Requires at least SDL 2.24.

* SDL Audio: Introduce <autoselect> device

Add an "autoselect" device which uses whatever SDL Audio deems
best.

* SDL Audio: simply deviceId setup

Previous patch introduced the autoselect device, which is always available.
Use it if the GUI/Settings selected DeviceId is out of range.

* SDL_Audio: remove always-false check

* remove outdated comment in sdlInit()

---------

Co-authored-by: luciusDXL <ldarkxl@gmail.com>

CMakeLists.txt

@@ -44,7 +44,6 @@ set_target_properties(tfe PROPERTIES OUTPUT_NAME "theforceengine")
 if(LINUX)
 	find_package(PkgConfig REQUIRED)
 	find_package(Threads REQUIRED)
-	pkg_check_modules(RTAUDIO REQUIRED rtaudio>=5.2.0)
 	pkg_check_modules(RTMIDI REQUIRED rtmidi>=5.0.0)
 	pkg_check_modules(SDL2 REQUIRED sdl2)
 	pkg_check_modules(GLEW REQUIRED glew)
@@ -60,7 +59,6 @@ if(LINUX)
 				${SDL2_LIBRARIES}
 				${IL_LIBRARIES}
 				${ILU_LIBRARIES}
-				${RTAUDIO_LIBRARIES}
 				${RTMIDI_LIBRARIES}
 	)
 

README.md

@@ -53,7 +53,6 @@ This can be overridden by defining the "__TFE_DATA_HOME__" environment variable.
 ### Required Libraries
 * [SDL2](TheForceEngine/TFE_FrontEndUI/frontEndUi.cpp) 2.24 or higher
 * [devIL](https://openil.sourceforge.net)
-* [RtAudio](https://www.music.mcgill.ca/~gary/rtaudio/) 5.2.0 or higher
 * [RtMidi](https://www.music.mcgill.ca/~gary/rtmidi/) 5.0.0 or higher
 * [GLEW](http://glew.sourceforge.net/) 2.2.0
 * OpenGL 3.3 capable driver (latest [mesa](https://www.mesa3d.org) or nvidia proprietary driver recommended)

TheForceEngine/Documentation/markdown/Credits.md

@@ -63,7 +63,7 @@ Most of the source code listed below is embedded within the project so that it c
 
 Note that some libraries will be replaced by custom code or simpler libraries in the future (such as DevIL).
 
-**Windowing/OpenGL**
+**Windowing/OpenGL/Audio**
 SDL 2.0.x
   * [https://www.libsdl.org/](https://www.libsdl.org/)
   * License: ZLIB
@@ -94,11 +94,7 @@ DevIL
   * [http://openil.sourceforge.net/](http://openil.sourceforge.net/)
   * License: LGPL 2.1
 
-**Audio**
-RtAudio (Core Audio I/O)
-  * [http://www.music.mcgill.ca/~gary/rtaudio/](http://www.music.mcgill.ca/~gary/rtaudio/)
-  * License: Custom
-
+**Music**
 RtMidi (Core Midi Hardware I/O)
   * [https://www.music.mcgill.ca/~gary/rtmidi/](https://www.music.mcgill.ca/~gary/rtmidi/)
   * License: Custom

TheForceEngine/TFE_Audio/CMakeLists.txt

@@ -1,7 +1,6 @@
 file(GLOB_RECURSE SOURCES "*.cpp" "*.c")
 if(LINUX)
 	# we use the system libraries on Linux
-	list(REMOVE_ITEM SOURCES "${CMAKE_CURRENT_SOURCE_DIR}/RtAudio.cpp")
 	list(REMOVE_ITEM SOURCES "${CMAKE_CURRENT_SOURCE_DIR}/RtMidi.cpp")
 endif()
 target_sources(tfe PRIVATE ${SOURCES})