; Gate.csd
; Written by Iain McCurdy, 2015.

; Two 'Processing Configutions' are available:
;  'Stereo Mixed' 		-	the two input channels are mixed before being sent to a single envelope follower. 
;					Subsequent processing (gating filtering) is still carried out on the stereo input, just the gate open/closed control data will be the same on both channels
;  'Stereo Separate' 		-	the two input channels are sent to independent envelope followers. 
;					Therefore gate open/closed control data for the two channels can differ.  
; Right Channel Sidechain	-	In this mode, the gate is triggered by the signal received in the right channel but the gated signal is the left channel 

; Input signal is sent to an envelope follower and a gate state (open/closed) is assessed according to user defined thresholds.
; Independent thresholds and time durations can be defined for gate opening and closing.

; Pre-filter filters the input signal through a highpass filter and lowpass filter in series. 
; (Note this is only the signal sent into the envelope follower and the signal sent to the actual gate and the then the output is unfiltered.)
; This feature can be used to fine tune gate opening for particular frequency bands. 
; E.G. Opening for a voice singing but not for low frequency rumble picked up through the microphone stand. 

; The 'Filter Gate' can gate the signal using a lowpass filter (either 12 dB/oct or 24 dB/oct). 
; The user sets the 'Min.' (gate closed) and 'Max.' (gate open) cutoff values for the filter (in oct format)

; 'Atten.' sets the amount of amplitude attenuation to be applied.
; 'Delay' delays the audio (after envelope following but before gating is applied)
;	This can be used to recover the attack of a sound, particularly if the attack time of the gate is long.
;	If delay time is zero then the delay is completely bypassed.  
                                                                       
<Cabbage>                                                                                                                   
form caption("Gate"), colour( 20, 20, 30), size(430, 305), pluginid("Gate"), scrollbars(0)

image     bounds(  5, 10,420, 40), shape("sharp"), outlinecolour("white"), colour(0,0,0,0), outlinethickness(1), plant("Input") {
label     bounds( 20, 10,180, 14), fontcolour("white"), text("Processing Configuration:"), colour(0,0,0,0), align("right")
combobox  bounds(202, 10,180, 16), channel("InputMode"), text("Stereo Mixed","Stereo Separate","Right Channel Side Chain"), value(1), colour( 70, 70, 70), fontcolour("white")
}

image     bounds(  5, 55,207, 90), shape("sharp"), outlinecolour("white"), colour(0,0,0,0), outlinethickness(1), plant("OnThresh") {
label     bounds(  0,  5,207, 12), fontcolour("white"), text("On Threshold"), colour(0,0,0,0)
rslider   bounds( 10, 20, 60, 60), range(0,0.1,0.01,0.5,0.0001),  channel("OnThresh"), text("Level"), textcolour("white")
numberbox bounds( 65, 35, 45, 15), channel("OnThresh_dB"), range(-90,120,-90,1,0.1)
label     bounds(110, 37, 20, 12), fontcolour("white"), text("dB"), colour(0,0,0,0)
rslider   bounds(135, 20, 60, 60), range(0,0.3,0.04,0.5,0.0001),  channel("AttTime"), text("Time"), textcolour("white")
}

image     bounds(218, 55,207, 90), shape("sharp"), outlinecolour("white"), colour(0,0,0,0), outlinethickness(1), plant("OffThresh") {
label     bounds(  0,  5,207, 12), fontcolour("white"), text("Off Threshold"), colour(0,0,0,0)
rslider   bounds( 10, 20, 60, 60), range(0,0.1,0.007,0.5,0.0001),  channel("OffThresh"), text("Level"), textcolour("white")
numberbox bounds( 65, 35, 45, 15), channel("OffThresh_dB"), range(-90,120,-90,1,0.1)
label     bounds(110, 37, 20, 12), fontcolour("white"), text("dB"), colour(0,0,0,0)
rslider   bounds(135, 20, 60, 60), range(0,0.3,0.03,0.5,0.0001),  channel("RelTime"), text("Time"), textcolour("white")
}

image    bounds(  5,150,420, 50), shape("sharp"), outlinecolour("white"), colour(0,0,0,0), outlinethickness(1), plant("PreFilter") {
checkbox bounds( 10, 15, 70, 12), channel("PreFiltOnOff"), text("Pre-Filter"), fontcolour("white")
;hslider2 bounds( 85,  0,330, 40), channel("HPF","LPF"), min(200), max(12000), range(20,20000, 0, 0.5, 1), identchannel("Filter")
hrange   bounds(  85,  5,330, 20), channel("HPF","LPF"), range(20, 20000, 200:12000, 0.5, 1), identchannel("Filter")
label    bounds( 85, 30,330, 12), text("Highpass / Lowpass"), fontcolour("white"), identchannel("FilterL")
}

image    bounds(  5,205,210, 95), shape("sharp"), outlinecolour("white"), colour(0,0,0,0), outlinethickness(1), plant("FilterGate") {
label    bounds(  5, 22, 80, 12), text("Filter Gate"), fontcolour("white")
combobox bounds(  5, 35, 80, 20), channel("FilterGate"), text("Bypass","12 dB/Oct","24 dB/Oct"), value(1)
rslider  bounds( 75,  5, 80, 80), range(2,14,2,0.5,0.01),  channel("FiltGateMin"), text("Min"), textcolour("white"), textbox(1)
rslider  bounds(135,  5, 80, 80), range(2,14,14,0.5,0.01),  channel("FiltGateMax"), text("Max"), textcolour("white"), textbox(1)
}

image    bounds(220,205,205, 95), shape("sharp"), outlinecolour("white"), colour(0,0,0,0), outlinethickness(1), plant("Master") {
checkbox bounds( 14, 30, 15, 13), channel("GateIndicOp"), shape("ellipse"), colour( 50,255, 50), active(0)
checkbox bounds( 14, 50, 15, 13), channel("GateIndicCl"), shape("ellipse"), colour(255, 50, 50), value(1), active(0)
rslider  bounds( 20,  5, 80, 80), range(0,90,90,0.5,0.1),  channel("Atten"), text("Atten."), textcolour("white"), textbox(1)
rslider  bounds( 75,  5, 80, 80), range(0,0.1,0,0.8,0.001),  channel("DelTim"), text("Delay"), textcolour("white"), textbox(1)
rslider  bounds(130,  5, 80, 80), range(0,2,1,0.5,0.01),  channel("Gain"), text("Gain"), textcolour("white"), textbox(1)
}

</Cabbage>

<CsoundSynthesizer>

<CsOptions>
-dm0 -n
</CsOptions>

<CsInstruments>

sr	=	44100
ksmps	=	32
nchnls	=	2
0dbfs	=	1

;Author: Iain McCurdy (2015)

opcode	SwitchPort, k, kkk
	kin,kupport,kdnport	xin
	kold			init	0
	kporttime		=	(kin<kold?kdnport:kupport)
	kout			portk	kin, kporttime
	kold			=	kout
				xout	kout
endop

instr	1
 /* READ IN WIDGETS */
 kOnThresh	chnget	"OnThresh"
 kOffThresh	chnget	"OffThresh"
 kAttTime	chnget	"AttTime"
 kRelTime	chnget	"RelTime"
 kAtten		chnget	"Atten"
 kGain		chnget	"Gain"
 kFilterGate	chnget	"FilterGate"
 kFiltGateMin	chnget	"FiltGateMin"
 kFiltGateMax	chnget	"FiltGateMax"
 kInputMode	chnget	"InputMode"
 kHPF		chnget	"HPF"
 kLPF		chnget	"LPF"
 kPreFiltOnOff		chnget	"PreFiltOnOff"
 kDelTim	chnget	"DelTim"
 
 kporttime	linseg	0,0.001,0.05		;
 kGain		portk	kGain,kporttime

 /* INPUT */
 ;aL,aR	diskin2	"029_HPF.wav",1,0,1	; use diskin for testing
 aL,aR	ins
 
 /* SHOW OR HIDE PRE-FILTER SLIDERS */
 if changed(kPreFiltOnOff)==1 then
  if kPreFiltOnOff==1 then
   	chnset	"visible(1)","Filter"
   	chnset	"visible(1)","FilterL"
  else
   	chnset	"visible(0)","Filter"  
   	chnset	"visible(0)","FilterL"  
  endif
 endif
 


 /* STEREO MIX MODE */
 if kInputMode==1 then
 
  aInSig	sum	aL,aR		; mix left and right inputs

  if kPreFiltOnOff==1 then		; if pre-filter switch is on...
   aInSig	buthp	aInSig,kHPF	; highpass filter
   aInSig	buthp	aInSig,kHPF	; and again to steepen slope
   aInSig	butlp	aInSig,kLPF	; lowpass filter
   aInSig	butlp	aInSig,kLPF	; and again to steepen slope
  endif


  kRMS	rms	aInSig			; scan rms of input signal

  /* OPEN AND CLOSE GATE*/
  kGate	init	1
  if kRMS < kOffThresh && kGate ==1 then
   kGate	=	0
  elseif kRMS >= kOnThresh && kGate == 0 then
   kGate	=	1
  endif
  
  /* TURN GATE STATUS INDICATORS ON AND OFF */
  if changed(kGate)==1 then
  	chnset	1-kGate,"GateIndicCl"
  	chnset	kGate,"GateIndicOp"
  endif
   
  /* SMOOTH GATE OPENING AND CLOSING (CALL UDO) */
  kGateD SwitchPort kGate, kAttTime, kRelTime	; smooth opening and closing
  
  /* AMPLITUDE GATE */
  kGateDA	scale	kGateD,1,ampdb(-kAtten)	; modify gating function according to user defined attenuation setting
  aGate	interp	kGateDA				; create an arate version (smoother)
    
  /* DELAY */
  if kDelTim>0 then
   aL	vdelay	aL, kDelTim*1000, 100
   aR	vdelay	aR, kDelTim*1000, 100
  endif
   
  /* APPLY GATE */
  aL	*=	aGate
  aR	*=	aGate
  
  /* FILTER GATE */
  if kFilterGate>1 then				
   kcfoct	scale	kGateD,kFiltGateMax,kFiltGateMin
   acf	interp	cpsoct(kcfoct)
   if kFilterGate==2 then
    aL	tone	aL,acf
    aR	tone	aR,acf
   else
    aL	butlp	aL,acf
    aR	butlp	aR,acf
   endif
  endif
    
    
    
    
    
 /* STEREO SEPARATE MODE */
 elseif kInputMode==2 then
 
 aInSigL	=	aL
 aInSigR	=	aR

  if kPreFiltOnOff==1 then
   aInSigL	buthp	aInSigL,kHPF
   aInSigL	buthp	aInSigL,kHPF
   aInSigL	butlp	aInSigL,kLPF
   aInSigL	butlp	aInSigL,kLPF
   aInSigR	buthp	aInSigR,kHPF
   aInSigR	buthp	aInSigR,kHPF
   aInSigR	butlp	aInSigR,kLPF
   aInSigR	butlp	aInSigR,kLPF
  endif


  kRMSL	rms	aInSigL*2
  kRMSR	rms	aInSigR*2

  kGateL,kGateR	init	1

  if kRMSL < kOffThresh && kGateL ==1 then
   kGateL	=	0
  elseif kRMSL >= kOnThresh && kGateL == 0 then
   kGateL	=	1
  endif

  if kRMSR < kOffThresh && kGateR ==1 then
   kGateR	=	0
  elseif kRMSR >= kOnThresh && kGateR == 0 then
   kGateR	=	1
  endif
  
  if changed(kGateL)==1 then
  	chnset	1-kGateL,"GateIndicCl"
  	chnset	kGateL,"GateIndicOp"
  endif
   
  kGateDL SwitchPort kGateL, kAttTime, kRelTime	; smooth opening and closing
  kGateDR SwitchPort kGateR, kAttTime, kRelTime	; smooth opening and closing
  
  kGateDAL	scale	kGateDL,1,ampdb(-kAtten)
  kGateDAR	scale	kGateDR,1,ampdb(-kAtten)
  
  aGateL	interp	kGateDAL
  aGateR	interp	kGateDAR
   
  /* DELAY */
  if kDelTim>0 then
   aL	vdelay	aL, kDelTim*1000, 100
   aR	vdelay	aR, kDelTim*1000, 100
  endif
   
  /* APPLY GATE */
  aL	*=	aGateL
  aR	*=	aGateR
  
  if kFilterGate>1 then
   kcfoctL	scale	kGateDL,kFiltGateMax,kFiltGateMin
   kcfoctR	scale	kGateDR,kFiltGateMax,kFiltGateMin
   acfL	interp	cpsoct(kcfoctL)
   acfR	interp	cpsoct(kcfoctR)
   if kFilterGate==2 then
    aL	tone	aL,acfL
    aR	tone	aR,acfR
   else
    aL	butlp	aL,acfL
    aR	butlp	aR,acfR
   endif
  endif



 ; Right Channel Side Chain
 else
 
  if kPreFiltOnOff==1 then		; if pre-filter switch is on...
   aR	buthp	aR,kHPF	; highpass filter
   aR	buthp	aR,kHPF	; and again to steepen slope
   aR	butlp	aR,kLPF	; lowpass filter
   aR	butlp	aR,kLPF	; and again to steepen slope
  endif


  kRMS	rms	aR			; scan rms of input signal

  /* OPEN AND CLOSE GATE*/
  kGate	init	1
  if kRMS < kOffThresh && kGate ==1 then
   kGate	=	0
  elseif kRMS >= kOnThresh && kGate == 0 then
   kGate	=	1
  endif
  
  /* TURN GATE STATUS INDICATORS ON AND OFF */
  if changed(kGate)==1 then
  	chnset	1-kGate,"GateIndicCl"
  	chnset	kGate,"GateIndicOp"
  endif
   
  /* SMOOTH GATE OPENING AND CLOSING (CALL UDO) */
  kGateD SwitchPort kGate, kAttTime, kRelTime	; smooth opening and closing
  
  /* AMPLITUDE GATE */
  kGateDA	scale	kGateD,1,ampdb(-kAtten)	; modify gating function according to user defined attenuation setting
  aGate	interp	kGateDA				; create an arate version (smoother)
    
  /* DELAY */
  if kDelTim>0 then
   aL	vdelay	aL, kDelTim*1000, 100
  endif
   
  /* APPLY GATE */
  aL	*=	aGate
  
  /* FILTER GATE */
  if kFilterGate>1 then				
   kcfoct	scale	kGateD,kFiltGateMax,kFiltGateMin
   acf	interp	cpsoct(kcfoct)
   if kFilterGate==2 then
    aL	tone	aL,acf
   else
    aL	butlp	aL,acf
   endif
  endif
  aR	=	aL

 endif
 	outs	aL*kGain, aR*kGain

endin

</CsInstruments>

<CsScore>
i 1 0 [3600*24*7]
</CsScore>

</CsoundSynthesizer>