classdef bubbleMIDI < audioPlugin

% audio plugin for producing bubble sounds

properties

%=================================== interfaced parameters

r = 0.01; % radius

%===================================

end

properties (Dependent)

trig = 'noteOff'; % noteState

end

properties (Access = private)

% vst parameters

fs; % sampling rate

buff; % buffer for generated waveform

readIndex = 1; % reading position in buffer

noteState = 'noteOff'; % note state

soundOut = 'false'; % decides whether to output the signal or not

%=================================== internal parameters

N; % signal length

a = 1; % initial amplitude

eps = 0.25; % epsilon

%===================================

end

properties (Constant)

PluginInterface = audioPluginInterface(...

audioPluginParameter('r','DisplayName','Radius','Mapping',{'lin',0.002,0.02}),...

audioPluginParameter('trig','DisplayName','Trigger','Mapping',{'enum','noteOff','noteOn_'}),...

'InputChannels',1,'OutputChannels',1);

end

methods

function obj = bubbleMIDI() % constructor

obj.fs = (getSampleRate(obj));

obj.N =(0:1/obj.fs:0.5);

obj.buff = zeros(length(obj.N),1);

end

function reset(obj)

obj.fs = (getSampleRate(obj));

obj.readIndex = 1;

obj.soundOut = 'false';

end

function set.trig(obj, val)

if val == 'noteOn_'

obj.readIndex = 1; % init readIndex

obj.soundOut = 'true_';

%=================================== sound synthesis

obj.buff = newBubble(obj.r, obj.N, obj.a, obj.eps)'; % generate waveform

%===================================

end

obj.noteState = val;

end

function val = get.trig(obj)

val = obj.noteState;

end

function out = process(obj, in)

if obj.soundOut == 'true_'

if obj.readIndex < length(obj.buff)-length(in) % buffer length not exceeded - output sound

out = obj.buff(obj.readIndex:length(in)+obj.readIndex-1); % read from buffer

obj.readIndex = obj.readIndex + length(in); % increment readIndex

else % buffer length exceeded - output zeros

obj.readIndex = 1; % init readIndex

obj.soundOut = 'false';

out = zeros(length(in),1);

end

else

out = zeros(length(in),1);

end

end

end

methods (Static)

function configureMIDI(obj,varargin)

% Configure MIDI connections.

privConfigureMIDI(obj,varargin{:});

end

function C = getMIDIConnections(obj)

% Get MIDI connections.

C = privConfigureMIDI('getConnections',obj);

end

function disconnectMIDI(obj)

% Disconnect MIDI controls.

privConfigureMIDI('disconnect',obj);

end

end

function bub = newBubble(r, N, a, eps)

f0 = 3/r; % fundamental frequency

d = 0.043 * f0 + 0.0014* f0^(3/2); % decay formula

sigma = eps*d; % sigma

ft = f0*(1+sigma*N); % rate of change in frequency over time

bub = a*sin(2*pi*ft.*N).*exp(-d*N); % calculation of the bubble