Fix latency on pulseaudio backend

README.md

@@ -16,12 +16,14 @@ Cross Platform device manager for driving and flight simulators, for use with co
 - Includes utility to configure revburner tachometer
 - Can send data to any serial device. So far only tested with arduino. Includes sample arduino sketch for sim lights.
 - The support for haptic bass shakers is limited and needs the most work. So far the engine rev is a simple sine wave, which I find convincing. The gear shift event works but not convincing enough for me.
+- Choice of Portaudio or Pulseaudio backend.
 
 ## Dependencies
 - libserialport - arduino serial devices
 - hidapi - usb hid devices
 - libusb - used by hidapi
 - portaudio - sound devices (haptic bass shakers)
+- pulseaudio - sound devices (haptic bass shakers)
 - libenet - UDP support (not yet implemented)
 - libxml2
 - argtable2
@@ -44,6 +46,11 @@ cmake ..
 make
 ```
 
+to use the pulseaudio backend use this cmake command
+```
+cmake -DUSE_PULSEAUDIO=YES ..
+```
+
 ## Testing
 
 ### Setting up Your Arduino Device

conf/monocoque.config

@@ -6,11 +6,18 @@ devices = ( {   device      = "USB";
                 granularity = 4;
                 config      = "/home/paul/.config/monocoque/revburner1.xml"; },
             {   device       = "Sound";
-                type        = "Engine"
+                type         = "Engine";
-                devid       = "98FD:83AC"; },
+                devid        = "alsa_output.usb-Generic_USB2.0_Device_20170726905959-00.analog-stereo";
+                pan          = 1;
+                volume       = 90;
+                frequency    = 27; },
             {   device       = "Sound";
                 type         = "Gear"
-                devid       = "98FD:83AC"; },
+                devid        = "alsa_output.usb-Generic_USB2.0_Device_20170726905959-00.analog-stereo";
+                pan          = 1;
+                duration     = .25;
+                volume       = 100;
+                frequency    = 27; },
             {   device      = "Serial";
                 type        = "ShiftLights";
                 config      = "None";

src/monocoque/devices/sound/usb_generic_shaker_pulse.c

@@ -123,7 +123,7 @@ int usb_generic_shaker_init(SoundDevice* sounddevice, pa_threaded_mainloop* main
 
     // recommended settings, i.e. server uses sensible values
     pa_buffer_attr buffer_attr;
-    buffer_attr.maxlength = (uint32_t) -1;
+    buffer_attr.maxlength = (uint32_t) 32767;
     buffer_attr.tlength = (uint32_t) -1;
     buffer_attr.prebuf = (uint32_t) -1;
     buffer_attr.minreq = (uint32_t) -1;
@@ -131,22 +131,17 @@ int usb_generic_shaker_init(SoundDevice* sounddevice, pa_threaded_mainloop* main
     pa_cvolume cv;
     uint16_t pvolume =  ceil(((double) volume/100.0d)*65535);
     // Settings copied as per the chromium browser source
-    pa_stream_flags_t stream_flags;
-    stream_flags = PA_STREAM_INTERPOLATE_TIMING |
-       PA_STREAM_NOT_MONOTONIC | PA_STREAM_AUTO_TIMING_UPDATE |
-       PA_STREAM_ADJUST_LATENCY;
 
-    //stream_flags = PA_STREAM_START_CORKED;
+    pa_stream_flags_t stream_flags;
+    stream_flags = PA_STREAM_INTERPOLATE_TIMING | PA_STREAM_NOT_MONOTONIC | PA_STREAM_AUTO_TIMING_UPDATE | PA_STREAM_ADJUST_LATENCY | PA_STREAM_START_CORKED;
+
     // Connect stream to the default audio output sink
     pa_cvolume_set(&cv, sample_specifications.channels, pvolume);
-    //pa_cvolume_set(&cv, 1, 0);
 
     pa_cvolume_set_balance(&cv, &channel_map, pan);
 
     assert(pa_stream_connect_playback(stream, devname, &buffer_attr, stream_flags, &cv, NULL) == 0);
 
-
-
     // Wait for the stream to be ready
     for(;;) {
         pa_stream_state_t stream_state = pa_stream_get_state(stream);

src/monocoque/gameloop/gameloop.c

@@ -203,10 +203,9 @@ int clilooper(SimDevice* devices, int numdevices, Parameters* p, SimData* simdat
         for (int x = 0; x < numdevices; x++)
         {
             devices[x].update(&devices[x], simdata);
-
         }
 
-    	if( poll(&mypoll, 1, 1000.0/DEFAULT_UPDATE_RATE) )
+    	if( poll(&mypoll, 1, 1000.0/update_rate) )
     	{
     	    scanf("%c", &ch);
     	    if(ch == 'q')