Add support for Web Audio (Emscripten/WebAssembly)

CMakeLists.txt

@@ -399,6 +399,25 @@ elseif(UNIX)
       set(PKGCONFIG_CFLAGS "${PKGCONFIG_CFLAGS} -DPA_USE_SNDIO=1")
       set(PKGCONFIG_REQUIRES_PRIVATE "${PKGCONFIG_REQUIRES_PRIVATE} sndio")
     endif()
+
+    if(EMSCRIPTEN)
+      option(PA_USE_WEBAUDIO "Enable support for Web Audio" ON)
+
+      if(PA_USE_WEBAUDIO)
+        target_sources(PortAudio PRIVATE
+          src/hostapi/webaudio/pa_webaudio.c
+        )
+        target_compile_definitions(PortAudio PUBLIC PA_USE_WEBAUDIO=1)
+        target_compile_options(PortAudio PUBLIC -pthread)
+        target_link_options(PortAudio PUBLIC -sASYNCIFY -sAUDIO_WORKLET -sWASM_WORKERS)
+        set(PKGCONFIG_CFLAGS "${PKGCONFIG_CFLAGS} -DPA_USE_WEBAUDIO=1")
+      endif()
+
+      # This makes it easy to run the examples. The default output format is .js
+      # and is set in the Emscripten toolchain file, so it cannot be overriden
+      # from the command-line with -DCMAKE_EXECUTABLE_SUFFIX.
+      set(CMAKE_EXECUTABLE_SUFFIX ".html")
+    endif()
   endif()
 endif()
 

src/hostapi/webaudio/README.txt

@@ -0,0 +1 @@
+pa_hostapi_skeleton.c provides a starting point for implementing support for a new host API with PortAudio. The idea is that you copy it to a new directory inside /hostapi and start editing.