Issue #305 - better handling of empty audio devices

Author: k1o0

+eui/SignalsTest.m

@@ -196,10 +196,21 @@
 
         InitializePsychSound
         d = PsychPortAudio('GetDevices');
-        d = d([d.NrOutputChannels] == 2);
-        [~,I] = min([d.LowOutputLatency]);
-        obj.Hardware.audioDevices = d(I);
-        obj.Hardware.audioDevices.DeviceName = 'default';
+        
+        % Keep output devices
+        d = d([d.NrOutputChannels] > 0);
+        obj.Hardware.audioDevices = d([d.NrOutputChannels] > 0);
+        
+        % Select the lowest latency stereo output as the default
+        stereo = [d.NrOutputChannels] == 2;
+        [~,I] = min([d(stereo).LowOutputLatency]);
+        I = I + sum(~stereo(1:I));
+        if isempty(I)
+          warning('Rigbox:eui:SignalsTest:NoStereoOutput', ...
+            'No stereo output audio devices detected; default unassigned')
+        else
+          obj.Hardware.audioDevices(I).DeviceName = 'default';
+        end
       else
         obj.Hardware = rig;
       end

alyx-matlab

@@ -78,6 +78,8 @@
 % * |git.listVersions| - Lists the previous versions of Rigbox availiable 
 % * |git.switchVersion| - Allows you to switched between Rigbox versions
 % * |git.repoVersion| - Returns release tag of repository, if available
+% * |eui.SignalsTest| - Warning instead of error when no stereo output
+% device found
 %
 % *Tests*
 %