supernova: enable building JACK API on macOS

README_MACOS.md

@@ -296,6 +296,55 @@ This should be fixed at some point (its a build tool configuration issue). Until
 
 They do however work on Linux and Windows.
 
+Building with native JACK backend
+------------------------------
+
+If you want to use `scsynth` or `supernova` on macOS with JACK, but _without_ the JackRouter driver, you can build them with the native JACK backend. **In that case you will not be able to boot `scsynth`/`supernova` without booting JACK first.** JackRouter allows any macOS application to stream audio to/from JACK, but at the time of writing this (early 2019) it is outdated and the development has stalled.
+
+First you need to install JACK, either through `homebrew`:
+
+```
+brew install jack qjackctl
+```
+
+or by installing the `JackOSX` package. Please note, JACK from `homebrew` is `jack1` and does _not_ include JackRouter. `JackOSX` is `jack2` and it does include JackRouter. `jack1` and `jack2` implement the same API, but you should have only one of them installed at a time.
+
+In order to build with JACK, you need to add the `-DAUDIOAPI=jack` flag to cmake.
+
+After running cmake configuration proceed with the build process as usual.
+
+### Running SuperCollider with JACK
+
+When `jack` is installed via `homebrew`, you need to add jack's path to the `$PATH` environment variable in `sclang`:
+
+```supercollider
+"PATH".setenv("echo $PATH".unixCmdGetStdOut ++ ":/usr/local/bin");
+```
+Please note, this is not needed when using the JackOSX package.
+
+Optionally, you can have `scsynth`/`supernova` automatically connect to system inputs/outputs by setting appropriate environment variables (refer to the Linux section of the "Audio device selection" reference in SuperCollider help):
+
+```supercollider
+// connect all input channels with system
+"SC_JACK_DEFAULT_INPUTS".setenv("system");
+// connect all output channels with system
+"SC_JACK_DEFAULT_OUTPUTS".setenv("system");
+```
+
+Now you can start JACK, either using `JackPilot` app (from JackOSX package), `qjackctl` (from `homebrew`) or from command line:
+
+
+```
+jackd -d coreaudio
+# or
+jackd -d coreaudio -r48000 -p512 # specifying sample rate and buffer size
+```
+
+Then start `scsynth`/`supernova` as usual.
+
+### Caveats
+
+JACK installed with `homebrew` can only use a single device for both input and output. In order to use it with the internal soundcard on macOS, one needs to create an aggregate device that includes both input and output. JACK from `JackOSX` does not have this limitation.
 
 sclang and scynth executables
 -----------------------------

server/scsynth/CMakeLists.txt

@@ -48,7 +48,7 @@ elseif(AUDIOAPI STREQUAL portaudio AND ((NOT WIN32) OR MSYS)) # MSYS like Apple
       message(FATAL_ERROR "Portaudio selected as audio API, but development files not found")
     endif()
 endif()
-message(STATUS "Audio API: ${AUDIOAPI}")
+message(STATUS "scsynth audio API: ${AUDIOAPI}")
 
 set(scsynth_sources
 	SC_BufGen.cpp

server/supernova/CMakeLists.txt

@@ -124,29 +124,48 @@ else()
   endif()
 endif()
 
-if(APPLE OR MSYS)
-    find_package(Portaudio)
-    if(NOT PORTAUDIO_FOUND)
-        message(FATAL_ERROR "Portaudio missing")
-    endif()
-    target_compile_definitions(libsupernova PUBLIC PORTAUDIO_BACKEND ${PORTAUDIO_DEFINITIONS})
-    target_include_directories(libsupernova PUBLIC ${PORTAUDIO_INCLUDE_DIRS})
-    target_link_libraries(libsupernova ${PORTAUDIO_LIBRARIES})
-elseif (WIN32)
-    target_compile_definitions(libsupernova PUBLIC PORTAUDIO_BACKEND -DPORTAUDIO_BACKEND)
-    target_include_directories(libsupernova PUBLIC ${PORTAUDIO_INCLUDE_DIRS})
-    if(MSYS)
-        target_link_libraries(libsupernova ${PORTAUDIO_LIBRARIES})
+if(AUDIOAPI STREQUAL "default")
+    if(APPLE)
+        set(AUDIOAPI portaudio)
+    elseif(WIN32)
+        set(AUDIOAPI portaudio)
     else()
-        target_link_libraries(libsupernova portaudio)
-    endif()
-else()
+        set(AUDIOAPI jack)
+    endif(APPLE)
+endif()
+
+if(NOT AUDIOAPI MATCHES "^(jack|coreaudio|portaudio)$")
+    message(FATAL_ERROR "Unrecognized audio API: ${AUDIOAPI}")
+endif()
+
+if(AUDIOAPI STREQUAL "coreaudio")
+    set(AUDIOAPI portaudio)
+    message(FATAL_ERROR "supernova: coreaudio API not implemented yet, use 'default' or 'portaudio' instead")
+endif()
+
+if(AUDIOAPI STREQUAL jack)
+    find_package(Jack REQUIRED)
+elseif(AUDIOAPI STREQUAL portaudio AND ((NOT WIN32) OR MSYS)) # MSYS like Apple
+    find_package(Portaudio REQUIRED)
+endif()
+message(STATUS "supernova audio API: ${AUDIOAPI}")
+
+if(AUDIOAPI STREQUAL jack)
     find_library(JACK NAMES jack)
-    if (JACK)
+    if(JACK)
         target_compile_definitions(libsupernova PUBLIC JACK_BACKEND)
         target_link_libraries(libsupernova ${JACK})
         target_include_directories(libsupernova PUBLIC ${JACK_INCLUDE_DIRS})
     endif()
+elseif(AUDIOAPI STREQUAL portaudio)
+    target_include_directories(libsupernova PUBLIC ${PORTAUDIO_INCLUDE_DIRS})
+    if(WIN32)
+        target_compile_definitions(libsupernova PUBLIC PORTAUDIO_BACKEND -DPORTAUDIO_BACKEND)
+        target_link_libraries(libsupernova portaudio)
+    else()
+        target_compile_definitions(libsupernova PUBLIC PORTAUDIO_BACKEND ${PORTAUDIO_DEFINITIONS})
+        target_link_libraries(libsupernova ${PORTAUDIO_LIBRARIES})
+    endif()
 endif()
 
 find_package(Sndfile)