added RAVEN HOA simulation example

applications/SoundFieldSimulation/Raven/ita_raven_demo_HOA.m

+%% RAVEN simulation: Example for HOA simulation of a shoebox (only encoded RIRs)
+% Author: las@akustik.rwth-aachen.de
+% date:     2019/06/26
+%
+% <ITA-Toolbox>
+% This file is part of the application Raven for the ITA-Toolbox. All rights reserved.
+% You can find the license for this m-file in the application folder.
+% </ITA-Toolbox>
+
+%% project settings
+ravenBasePath = 'C:\ITASoftware\Raven\';
+myLength=9;
+myWidth=7;
+myHeight=3;
+projectName = [ 'myHOA_ShoeboxRoom' num2str(myLength) 'x' num2str(myWidth) 'x' num2str(myHeight) ];
+
+%% create project and set input data
+rpf = itaRavenProject([ ravenBasePath 'RavenInput\Classroom\Classroom.rpf' ]);   % modify path if not installed in default directory
+rpf.copyProjectToNewRPFFile([ ravenBasePath 'RavenInput\' projectName '.rpf' ]);
+rpf.setProjectName(projectName);
+rpf.setModelToShoebox(myLength,myWidth,myHeight);
+
+rpf.setNumParticles(60000); % 60,000 particles for ray tracing simulation
+rpf.setFilterLength(2000);  % FilterLength (in ms)
+rpf.setISOrder_PS(2);       % set Image source order
+ 
+%% HOA configuration 
+rpf.setGenerateBRIR(0);     % deactivate binaural filters 
+rpf.setGenerateRIR(0);      % deactivate mono filters
+rpf.setGenerateISHOA(1);    % activate HOA for image sources
+rpf.setGenerateRTHOA(1);    % activate HOA for ray tracing 
+rpf.setAmbisonicsOrder(2);  % set HOA Order
+
+%% adjust wall materials of room
+for iMat=1:6
+    myAbsorp = 0.1 * ones(1,31);    % 10% absorption for all walls
+    myScatter = 0.3 * ones(1,31);   % 30% scattering for all walls
+    rpf.setMaterial(rpf.getRoomMaterialNames{iMat},myAbsorp,myScatter);
+end
+
+%% start simulation
+rpf.run;
+
+%% get results: RAVEN HOA results use the ANC notation: https://en.wikipedia.org/wiki/Ambisonic_data_exchange_formats#ACN
+RIRs = rpf.getAmbisonicsImpulseResponseItaAudio; % as ITA audio object
+RIRs_raw = rpf.getAmbisonicsImpulseResponse;     % as matrix
+
+%% check results
+ita_plot_time_dB(RIRs);
+
+%% and now?
+%  results need to be convolved with an anechoic signal (ita_convolve) 
+%  and then decoded using a HOA decoder, e.g., using
+%  ita_hoa_decode(Bformat, LoudspeakerPos, varargin) for B-Format signals
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