function MKS_05b
% MKS 05b - TIME-VARYING AUDIO PROCESSOR / SOUND EFFECT DESIGN
% Editable control tracks: F0(t), ZERO z0(t), POLE p(t), AMPLITUDE A(t).
% Click: add/move point; drag: edit; right click near point: remove.
% Shared timeline with input/output waveform; cursor shows instantaneous H(f).
% Standalone MATLAB (no Audio Toolbox). Offline processing.

fs=44100;
C.bg=[.96 .97 .98]; C.blue=[.12 .39 .78]; C.red=[.85 .34 .19];
C.green=[.18 .58 .40]; C.gray=[.52 .56 .61];
S.fs=fs; S.x=[]; S.y=[]; S.file=''; S.player=[];
S.source=2; S.duration=5; S.f0=160; S.pw=.5;
S.tEnd=5; S.cursor=0; S.dirty=true; S.drag=0; S.dragIndex=0;
S.points={ [0 160;5 160], [0 0;5 0], [0 0;5 0], [0 1;5 1] };
S.names={'F0 (Hz)','ZERO z_0(t)','POLE p(t)','AMPLITUDE A(t)'};
S.limits=[20 2000;-1 1;-.98 .98;0 1];
S.colors={[.55 .27 .75],C.blue,C.red,C.green};

fig=figure('Name','MKS 05b - TIME-VARYING AUDIO PROCESSOR', ...
 'NumberTitle','off','MenuBar','none','ToolBar','none','Color',C.bg, ...
 'Position',[75 50 1390 845],'Resize','off', ...
 'WindowButtonMotionFcn',@mouseMove,'WindowButtonUpFcn',@mouseUp, ...
 'CloseRequestFcn',@closeApp);
set(fig,'DefaultUicontrolFontName','Arial');
uicontrol(fig,'Style','text','String','MKS 05b  -  TIME-VARYING AUDIO PROCESSOR', ...
 'Position',[26 806 1310 30],'BackgroundColor',C.bg, ...
 'ForegroundColor',[.12 .18 .27],'FontSize',19,'FontWeight','bold', ...
 'HorizontalAlignment','left');

% Six vertically aligned tracks, same horizontal time scale.
left=70; wide=815; height=88;
ys=[690 568 446 324 202 80];
S.ax=gobjects(1,6); S.lines=gobjects(1,6); S.nodes=gobjects(1,4);
trackTitles={'INPUT / SOURCE','F0 (Hz)','ZERO z_0(t)', ...
 'POLE p(t)','AMPLITUDE A(t)','FILTERED OUTPUT'};
for k=1:6
 S.ax(k)=axes('Parent',fig,'Units','pixels','Position',[left ys(k) wide height]);
 hold(S.ax(k),'on'); grid(S.ax(k),'on');
 title(S.ax(k),trackTitles{k},'FontWeight','bold','FontSize',10);
 xlim(S.ax(k),[0 S.tEnd]);
 if k==2,ylim(S.ax(k),[20 2000]);set(S.ax(k),'YScale','log');
 elseif k==5,ylim(S.ax(k),[-.05 1.05]);
 else,ylim(S.ax(k),[-1.05 1.05]);end
 if k==6,xlabel(S.ax(k),'Time (s)');end
end
for k=1:4
 a=S.ax(k+1); col=S.colors{k};
 S.lines(k+1)=plot(a,nan,nan,'-','Color',col,'LineWidth',2, ...
   'HitTest','off');
 S.nodes(k)=plot(a,nan,nan,'o','Color',col,'MarkerFaceColor',col, ...
   'MarkerSize',6,'HitTest','off');
 set(a,'ButtonDownFcn',{@trackClick,k});
end
S.lines(1)=plot(S.ax(1),nan,nan,'Color',C.blue,'HitTest','off');
S.lines(6)=plot(S.ax(6),nan,nan,'Color',C.red,'HitTest','off');
S.cursorLines=gobjects(1,6);
for k=1:6
 if k==2,cy=[20 2000];else,cy=[-1.1 1.1];end
 S.cursorLines(k)=plot(S.ax(k),[0 0],cy,':', ...
  'Color',C.gray,'LineWidth',1,'HitTest','off');
end
% Clicking waveforms moves time cursor.
set(S.ax(1),'ButtonDownFcn',@cursorClick);
set(S.ax(6),'ButtonDownFcn',@cursorClick);

S.axH=axes('Parent',fig,'Units','pixels','Position',[1010 578 315 172]);
title(S.axH,'FILTER RESPONSE','FontSize',11);grid(S.axH,'on');
xlabel(S.axH,'Frequency (Hz)');ylabel(S.axH,'dB');
S.axZ=axes('Parent',fig,'Units','pixels','Position',[1050 345 235 185]);
title(S.axZ,'POLE / ZERO','FontSize',11);grid(S.axZ,'on');

uicontrol(fig,'Style','text','String','SOURCE', ...
 'Position',[940 291 120 22],'BackgroundColor',C.bg,'FontWeight','bold', ...
 'HorizontalAlignment','left');
S.ui.source=uicontrol(fig,'Style','popupmenu', ...
 'String',{'WAV FILE','NOISE','SINE','TRIANGLE','SAW','PULSE'}, ...
 'Value',2, 'Position',[1060 287 240 29],'FontSize',11,'Callback',@sourceChanged);

uicontrol(fig,'Style','text','String','DURATION (s)', ...
 'Position',[940 252 120 22],'BackgroundColor',C.bg,'HorizontalAlignment','left');
S.ui.duration=uicontrol(fig,'Style','edit','String','5', ...
 'Position',[1060 249 95 29],'FontSize',11,'Callback',@sourceSettings);
uicontrol(fig,'Style','text','String','F0 (Hz)', ...
 'Position',[1170 252 90 22],'BackgroundColor',C.bg);
S.ui.f0=uicontrol(fig,'Style','edit','String','160', ...
 'Position',[1260 249 70 29],'FontSize',11,'Callback',@sourceSettings);
uicontrol(fig,'Style','text','String','PULSE WIDTH (%)', ...
 'Position',[940 211 155 22],'BackgroundColor',C.bg,'HorizontalAlignment','left');
S.ui.pw=uicontrol(fig,'Style','slider','Min',5,'Max',95,'Value',50, ...
 'Position',[1100 210 165 24],'Callback',@sourceSettings);
S.ui.pwLabel=uicontrol(fig,'Style','text','String','50', ...
 'Position',[1270 211 60 22],'BackgroundColor',C.bg);

% Transport grouped by workflow: left = input, right = output.
S.ui.load=mkbutton(944,163,185,'LOAD WAV',@loadWav,[.24 .38 .55]);
S.ui.generate=mkbutton(944,117,185,'GENERATE',@generateSource,C.blue);
S.ui.playIn=mkbutton(944,71,185,'PLAY INPUT',@playInput,[.25 .52 .39]);
S.ui.stop=mkbutton(944,25,185,'STOP',@stopPlayback,[.55 .34 .34]);
S.ui.reset=mkbutton(1142,163,185,'RESET TRACKS',@resetTracks,[.48 .49 .52]);
S.ui.process=mkbutton(1142,117,185,'PROCESS',@processAudio,C.blue);
S.ui.playOut=mkbutton(1142,71,185,'PLAY OUTPUT',@playOutput,[.25 .52 .39]);
S.ui.save=mkbutton(1142,25,185,'SAVE WAV',@saveOutput,[.34 .39 .50]);
S.ui.status=uicontrol(fig,'Style','text','String', ...
 'Click to add points; drag to move; right-click to delete. Click waveform for filter snapshot.', ...
 'Position',[70 13 812 30],'BackgroundColor',C.bg, ...
 'HorizontalAlignment','left','FontSize',10);
S.ui.filename=uicontrol(fig,'Style','text','String','No WAV loaded', ...
 'Position',[940 323 420 20],'BackgroundColor',C.bg, ...
 'HorizontalAlignment','left','ForegroundColor',C.gray);

% Start with generated noise: no external WAV needed.
guidata(fig,S);
updateSourceControls();
generateSource();

 function color=ternaryColor(periodic)
  if periodic,color=[1 1 1];else,color=[.94 .94 .94];end
 end

 function x=synthesizeSource(q,N)
  % F0 track drives the oscillator's continuous phase (cycles).
  % Integral of instantaneous frequency prevents phase resets at nodes.
  if q.source==2
   x=.25*randn(N,1);return;
  end
  if q.source==1
   x=q.x;return;
  end
  tt=(0:N-1)'/q.fs;
  freq=interp1(q.points{1}(:,1),q.points{1}(:,2),tt,'linear','extrap');
  freq=max(20,min(2000,freq));
  phase=cumsum([0;freq(1:end-1)])/q.fs;
  ph=mod(phase,1);
  switch q.source
   case 3,x=.55*sin(2*pi*phase);
   case 4,x=.55*(4*abs(ph-.5)-1);
   case 5,x=.55*(2*ph-1);
   case 6,x=.55*(2*(ph<q.pw)-1);
  end
 end

 function h=mkbutton(x,y,w,label,cb,color)
  h=uicontrol(fig,'Style','pushbutton','String',label,'Position',[x y w 36], ...
   'FontWeight','bold','FontSize',10,'ForegroundColor','w', ...
   'BackgroundColor',color,'Callback',cb);
 end

 function sourceChanged(~,~)
  q=guidata(fig);q.source=get(q.ui.source,'Value');guidata(fig,q);
  updateSourceControls();
  if q.source==1
   setStatus('Choose LOAD WAV.');
  else
   setStatus('Press GENERATE for selected source.');
  end
 end

 function updateSourceControls()
  q=guidata(fig);periodic=q.source>=3;
  if periodic,onoff='on';else,onoff='off';end
  set(q.ui.f0,'Enable',onoff);
  set(q.ax(2),'Color',ternaryColor(periodic));
  if q.source==6,po='on';else,po='off';end
  set(q.ui.pw,'Enable',po);
 end

 function sourceSettings(~,~)
  q=guidata(fig);
  q.duration=clamp(readNumber(q.ui.duration,q.duration),.1,60);
  newF0=clamp(readNumber(q.ui.f0,q.f0),20,2000);
  if newF0~=q.f0
   q.points{1}(:,2)=newF0; q.dirty=true;
  end
  q.f0=newF0;
  q.pw=get(q.ui.pw,'Value')/100;
  set(q.ui.duration,'String',sprintf('%.2f',q.duration));
  set(q.ui.f0,'String',sprintf('%.1f',q.f0));
  set(q.ui.pwLabel,'String',sprintf('%.0f',100*q.pw));
  guidata(fig,q);
  setStatus('Source settings changed. Press GENERATE.');
 end

 function n=readNumber(h,default)
  n=str2double(strrep(get(h,'String'),',','.'));
  if ~isfinite(n),n=default;end
 end

 function generateSource(varargin)
  sourceSettingsNoStatus();q=guidata(fig);
  if q.source==1
   setStatus('Select a WAV file using LOAD WAV.');return;
  end
  stopAudio();
  N=max(1,round(q.duration*q.fs));
  q=resizeTimeline(q,N/q.fs);
  x=synthesizeSource(q,N);
  q.x=x;q.y=[];q.file='';q.dirty=true;
  guidata(fig,q);refreshAll();
  set(q.ui.filename,'String',sprintf('Generated: %d Hz, %.2f s',q.fs,q.tEnd));
  setStatus('Source ready. Edit F0 / filter / AM tracks, then PROCESS.');
 end

 function sourceSettingsNoStatus()
  q=guidata(fig);
  q.duration=clamp(readNumber(q.ui.duration,q.duration),.1,60);
  newF0=clamp(readNumber(q.ui.f0,q.f0),20,2000);
  if newF0~=q.f0
   q.points{1}(:,2)=newF0; q.dirty=true;
  end
  q.f0=newF0;
  q.pw=get(q.ui.pw,'Value')/100;
  set(q.ui.duration,'String',sprintf('%.2f',q.duration));
  set(q.ui.f0,'String',sprintf('%.1f',q.f0));
  set(q.ui.pwLabel,'String',sprintf('%.0f',q.pw*100));
  guidata(fig,q);
 end

 function loadWav(~,~)
  [name,folder]=uigetfile({'*.wav','WAV files (*.wav)'},'Select WAV');
  if isequal(name,0),return;end
  try
   [x,sampleRate]=audioread(fullfile(folder,name));
   if isempty(x),error('Empty audio file.');end
   if size(x,2)>2,x=x(:,1:2);end
   stopAudio();q=guidata(fig);
   q.x=x;q.y=[];q.fs=sampleRate;q.source=1;
   q.file=fullfile(folder,name);q.dirty=true;
   q=resizeTimeline(q,size(x,1)/sampleRate);
   set(q.ui.source,'Value',1);
   set(q.ui.filename,'String',sprintf('%s | %.2f s | %d Hz', ...
     name,q.tEnd,q.fs));
   guidata(fig,q);updateSourceControls();refreshAll();
   setStatus('WAV loaded. Edit control tracks and press PROCESS.');
  catch ME
   errordlg(ME.message,'WAV error');
  end
 end

 function q=resizeTimeline(q,newEnd)
  oldEnd=q.tEnd;q.tEnd=newEnd;q.cursor=min(q.cursor,newEnd);
  for j=1:4
   pts=q.points{j};
   if oldEnd>0,pts(:,1)=pts(:,1)*(newEnd/oldEnd);end
   pts(1,1)=0;pts(end,1)=newEnd;
   q.points{j}=pts;
  end
 end

 function resetTracks(~,~)
  q=guidata(fig);
  q.points={ [0 q.f0;q.tEnd q.f0],[0 0;q.tEnd 0], ...
   [0 0;q.tEnd 0],[0 1;q.tEnd 1] };
  q.dirty=true;guidata(fig,q);refreshAll();
  setStatus('Tracks reset: F0 constant, z0=0, p=0, A=1.');
 end

 function trackClick(~,~,j)
  q=guidata(fig);a=q.ax(j+1);cp=get(a,'CurrentPoint');
  tx=clamp(cp(1,1),0,q.tEnd);
  val=clamp(cp(1,2),q.limits(j,1),q.limits(j,2));
  pts=q.points{j};
  % Select existing node if near in normalized screen coordinates.
  span=q.limits(j,2)-q.limits(j,1);
  if j==1
   yDist=(log(pts(:,2))-log(val))/(log(2000)-log(20));
  else
   yDist=(pts(:,2)-val)/span;
  end
  dist=hypot((pts(:,1)-tx)/max(q.tEnd,eps),yDist);
  [d,idx]=min(dist);
  rightClick=strcmp(get(fig,'SelectionType'),'alt');
  if rightClick
   if d<.045 && idx>1 && idx<size(pts,1)
    pts(idx,:)=[];q.points{j}=pts;q.dirty=true;
   end
   q.drag=0;guidata(fig,q);refreshAll();return;
  end
  if d>=.045
   pts=[pts;tx val];pts=sortrows(pts,1);
   [~,idx]=min(abs(pts(:,1)-tx));
  else
   pts(idx,2)=val;
  end
  if idx==1,pts(idx,1)=0;end
  if idx==size(pts,1),pts(idx,1)=q.tEnd;end
  q.points{j}=pts;q.drag=j;q.dragIndex=idx;q.dirty=true;
  q.cursor=tx;guidata(fig,q);refreshAll();
 end

 function mouseMove(~,~)
  q=guidata(fig);
  if q.drag==0,return;end
  j=q.drag;idx=q.dragIndex;pts=q.points{j};
  cp=get(q.ax(j+1),'CurrentPoint');
  tx=clamp(cp(1,1),0,q.tEnd);
  val=clamp(cp(1,2),q.limits(j,1),q.limits(j,2));
  if idx==1,tx=0;
  elseif idx==size(pts,1),tx=q.tEnd;
  else
   gap=max(q.tEnd*1e-5,1e-6);
   tx=clamp(tx,pts(idx-1,1)+gap,pts(idx+1,1)-gap);
  end
  pts(idx,:)=[tx val];q.points{j}=pts;q.cursor=tx;q.dirty=true;
  guidata(fig,q);refreshControl(j);refreshCursor();updateResponse();
 end

 function mouseUp(~,~)
  q=guidata(fig);q.drag=0;guidata(fig,q);
 end

 function cursorClick(src,~)
  q=guidata(fig);cp=get(src,'CurrentPoint');
  q.cursor=clamp(cp(1,1),0,q.tEnd);
  guidata(fig,q);refreshCursor();updateResponse();
 end

 function refreshAll()
  q=guidata(fig);
  for j=1:6
   xlim(q.ax(j),[0 max(q.tEnd,.001)]);
  end
  refreshWaveforms();
  for j=1:4,refreshControl(j);end
  refreshCursor();updateResponse();
 end

 function refreshWaveforms()
  q=guidata(fig);
  plotWave(q.lines(1),q.x,q.fs);
  plotWave(q.lines(6),q.y,q.fs);
 end

 function plotWave(h,x,sampleRate)
  if isempty(x),set(h,'XData',nan,'YData',nan);return;end
  N=size(x,1);step=max(1,ceil(N/4000));idx=1:step:N;
  set(h,'XData',(idx-1)/sampleRate,'YData',x(idx,1));
 end

 function refreshControl(j)
  q=guidata(fig);pts=q.points{j};
  set(q.lines(j+1),'XData',pts(:,1),'YData',pts(:,2));
  set(q.nodes(j),'XData',pts(:,1),'YData',pts(:,2));
 end

 function refreshCursor()
  q=guidata(fig);
  for j=1:6
   set(q.cursorLines(j),'XData',[q.cursor q.cursor]);
  end
 end

 function updateResponse()
  q=guidata(fig);t=q.cursor;
  f0=interp1(q.points{1}(:,1),q.points{1}(:,2),t,'linear');
  z=interp1(q.points{2}(:,1),q.points{2}(:,2),t,'linear');
  p=interp1(q.points{3}(:,1),q.points{3}(:,2),t,'linear');
  A=interp1(q.points{4}(:,1),q.points{4}(:,2),t,'linear');
  w=linspace(0,pi,650);fr=w*q.fs/(2*pi);
  H=(1-z*exp(-1i*w))./(1-p*exp(-1i*w));
  plot(q.axH,fr,20*log10(max(abs(H),1e-6)),'Color',C.blue,'LineWidth',1.6);
  xlim(q.axH,[0 q.fs/2]);grid(q.axH,'on');
  title(q.axH,sprintf('FILTER RESPONSE | t=%.2fs',t),'FontSize',10);
  xlabel(q.axH,'Frequency (Hz)');ylabel(q.axH,'dB');
  th=linspace(0,2*pi,250);
  cla(q.axZ);hold(q.axZ,'on');
  plot(q.axZ,cos(th),sin(th),'Color',C.gray);
  plot(q.axZ,[-1.1 1.1],[0 0],':','Color',C.gray);
  plot(q.axZ,[0 0],[-1.1 1.1],':','Color',C.gray);
  plot(q.axZ,z,0,'o','Color',C.blue,'MarkerSize',10,'LineWidth',2);
  plot(q.axZ,p,0,'x','Color',C.red,'MarkerSize',11,'LineWidth',2);
  hold(q.axZ,'off');axis(q.axZ,'equal');
  xlim(q.axZ,[-1.1 1.1]);ylim(q.axZ,[-1.1 1.1]);grid(q.axZ,'on');
  title(q.axZ,sprintf('F0=%.0f Hz | z=%.2f p=%.2f A=%.2f',f0,z,p,A),'FontSize',9);
 end

 function processAudio(~,~)
  q=guidata(fig);
  if isempty(q.x),setStatus('Load WAV or GENERATE a source first.');return;end
  stopAudio();setStatus('Processing...');drawnow;
  try
   N=size(q.x,1);nch=size(q.x,2);
   tt=(0:N-1)'/q.fs;
   if q.source>=3
    q.x=synthesizeSource(q,N);
    guidata(fig,q);
   end
   z=interp1(q.points{2}(:,1),q.points{2}(:,2),tt,'linear');
   p=interp1(q.points{3}(:,1),q.points{3}(:,2),tt,'linear');
   amp=interp1(q.points{4}(:,1),q.points{4}(:,2),tt,'linear');
   % Preserve filter states independently for each channel.
   y=zeros(N,nch);xp=zeros(1,nch);yp=zeros(1,nch);
   for n=1:N
    v=q.x(n,:)-z(n)*xp+p(n)*yp;
    y(n,:)=amp(n)*v;
    xp=q.x(n,:);yp=v;
   end
   peak=max(abs(y(:)));
   scale=min(1,.98/max(peak,eps));y=y*scale;
   q.y=y;q.dirty=false;guidata(fig,q);
   refreshWaveforms();
   setStatus(sprintf('Processed %.2f s | pre-limiter peak %.2f | gain %.3f', ...
    q.tEnd,peak,scale));
  catch ME
   errordlg(ME.message,'Processing error');setStatus('Processing failed.');
  end
 end

 function playInput(~,~)
  q=guidata(fig);
  if isempty(q.x),setStatus('Generate or load a source first.');return;end
  playSignal(q.x,q.fs,'Playing input...');
 end
 function playOutput(~,~)
  q=guidata(fig);
  if isempty(q.y)||q.dirty
   setStatus('Press PROCESS after editing the tracks.');return;
  end
  playSignal(q.y,q.fs,'Playing output...');
 end
 function playSignal(x,sampleRate,msg)
  stopAudio();
  try
   pl=audioplayer(x,sampleRate);
   q=guidata(fig);q.player=pl;guidata(fig,q);
   play(pl);setStatus(msg);
  catch ME,errordlg(ME.message,'Playback error');end
 end
 function stopPlayback(~,~)
  stopAudio();setStatus('Stopped.');
 end
 function stopAudio()
  if ~ishandle(fig),return;end
  q=guidata(fig);
  if ~isempty(q.player)
   try,stop(q.player);catch,end
   q.player=[];guidata(fig,q);
  end
 end
 function saveOutput(~,~)
  q=guidata(fig);
  if isempty(q.y)||q.dirty,setStatus('Press PROCESS before SAVE WAV.');return;end
  [name,folder]=uiputfile('*.wav','Save processed WAV','MKS_05b_output.wav');
  if isequal(name,0),return;end
  try
   audiowrite(fullfile(folder,name),q.y,q.fs,'BitsPerSample',24);
   setStatus(['Saved: ' fullfile(folder,name)]);
  catch ME,errordlg(ME.message,'Save error');end
 end
 function setStatus(msg)
  if ~ishandle(fig),return;end
  q=guidata(fig);set(q.ui.status,'String',msg);
 end
 function closeApp(~,~)
  stopAudio();if ishandle(fig),delete(fig);end
 end
end

function x=clamp(x,a,b)
x=max(a,min(b,x));
end