CV

Extension

Description

A CV models a single floating point value or an array of such values constrained to a specific numerical range by a ControlSpec. SV is a derived class that defines an index into an array.

CV is derived from Stream so it can be used directly in Stream and Pattern definitions. CV:connect(view) will connect a CV to a GUI ControlView in both Cocoa and Swing. GUI representations. A similar set of methods have been defined that connect argument arrays consisting of keys and CVs to nodes, buses, buffers, and NodeProxys.

An SV is a CV that models an index into an array of Symbols. The array is held in the instance variable items. The symbol corresponding to the CV's current value can be accessed with the method item.

Class Methods

.new

Instance Methods

Setting the range of values on existing CVs

.spec

.sp

.connect

Accessing

.value

.input

.value

.windex

.indexedBy

CV connections using SimpleControllers

When a CV's value is changed a changed message (with 'synch' as the identifier) is send to update any dependant objects. For example, action_(function) creates a SimpleController which is added to the dependants of the CV and evaluated whenever the CV changes value. This same basic mechanism is used to connect the CV to GUI's, server, objects, and some other objects in the language. Most of this is more or less hidden from view.

Under normal circumstances, CV connections are automatically removed when the targeted Control, Bus, or View is deleted. If there is a program error, it is possible that connections will persist and will need to be explicitly removed.

.action

.release

GUI connections

The following methods establish connections between Views and CVs.

One CV can be connected to many views but each view is connected to only one CV.

When a CV's value changes, it is relayed to all of its dependants including the source of the the change. That way, the GUI accurately reflects the new value of the CV. See the behavior of 'b' in the following example.

The following example provides a generic graphic interface to two CVs. Subsequent examples depend on that window, so leave it open until you are finished working through the help file. (The interpreter variables 'a' and 'b' contain the CVs used by the examples, so they should be left unaltered.)( a = CV(\freq); // create a couple of CVs b = CV.new.sp(-10,-100,20, 10); w = Window("CV Demo", Rect(64, 0, 400, 300)).front; // make a window w.view.decorator = FlowLayout(w.view.bounds); // CVs can be connected to QSlider and QNumberBox. z = QNumberBox(w, Rect(0, 0, 50, 20)); a.connect(z); y = QSlider(w, Rect(50, 0, 150, 20)); a.connect(y); w.view.decorator.nextLine; b.connect( QNumberBox(w, Rect(0, 0, 50, 20)) ); b.connect( QSlider(w, Rect(50, 0, 150, 20)) ); w.view.decorator.nextLine; // Pairs of CVs can be connected to QRangeSlider, QSlider2D . r = QRangeSlider(w, Rect(0, 0, 200, 20)); [a,b].connect(r); t = QSlider2D(w, Rect(0, 0, 200, 200)); [a,b].connect(t); )

Server connections

OSC commands (i.e., /n_set, /s_new) specify initial values of parameters as a flat array of pairs consisting of a name and its initial value:[frequency: 440, amplitude: 1, ...]

"Extended argument arrays" allow CVs to be used in place of the initial value. This is the standard syntax for establishing connections between CVs and a server. In an extended argument array, the CV's value can be altered before being sent, multiple CV's can determine the value to be sent, and the value to be sent can be determined by a function:

For example, the method Synth-controls is identical to Synth-new except the args parameter is extended:// Synth-controls(defName, extendedArgArray, target, addAction) ( // basic CV connection Synth.controls("default", [ freq: a ]); ) ( // modified CV connection Synth.controls("default", [ amp: [b, b.dbamp], freq: a ]); ) (// multiple modified connection Synth.controls("default", [ freq: [ [a,b], a + b, ], amp: [ [a,b], (a.cpsmidi.neg/4 + b).dbamp ] ]); )

In the previous two examples, the modifying expression is actually a combination of Streams altered with binary and unary operators. This is concise, but in some cases, it may be necessary to use a Function to define the modification. Notice that within a Function definition it is necessary to explicitly extract the value of the CV using a value message.(// a Function modifying the CV connection Synth.controls("default", [ freq: [b, { var index; (index = b.value + 100 /12 ).asInteger; [100,200,300,400,500, 600].mirror.at(index) }], amp: [ [a,b], {(a.value.cpsmidi.neg/4 + b.value).dbamp } ] ]); )

Summary of Node related connection methods

Array

connectToNode(server, nodeID)

connectToNodeProxy(server, nodeID)

the receiver is a flat Array of name/value pairs

connectToBuffer(server, bufnum)

connectToBus(server, index)

the receiver is an Array of CVs.

Node

setControls(extendedArgArray)

NodeProxy

setControls(extendedArgArray)

connects CVs to the named controls

( c = CV.new.sp(-20, -100, 120); p = NodeProxy.audio(s, 2); p.play; //play to hardware output, return a group with synths p.setControls([f: a, c: [b, { \freq.asSpec.map(b.input)}] ]); b.input_(0.5); p.source = { arg f=400, c = 400; PMOsc.ar(f , c, 4, 0, 0.1) }; )

Synth

*controls(synthDef, extendedArgArray, target, addAction)

This is the same as *new, but allows CV's to be used in the args array.

Bus

*controls(arrayOfCVs, server)

( c = { arg f = 400, a = -20, pan = 0; Pan2.ar(SinOsc.ar(f, 0, a.dbamp), pan) }.play; d = Bus.controls([a,b],s); [a,b].connectToBus(d.server, d.index); Routine({ // need to make sure the synth has been created... s.sync; c.map(\f,d.index,\a,d.index + 1); }).play; )

setControls(arrayOfCVS)

connects CVs to consecutive buses( c = { arg f = 400, a = -20, pan = 0; Pan2.ar(SinOsc.ar(f, 0, a.dbamp), pan) }.play; d = Bus.control(s,3); d.setControls([a,b]); [a,b].connectToBus(d.server, d.index); Routine({ // need to make sure the synth has been created... s.sync; c.map(\f,d.index,\a,d.index + 1); }).play; )

Reading and writing CVs in functions and patterns

Tasks

Within a function, CVs are accessed using value and input and altered using value_ and input_.( Task({ 10.do({ a.input.post; " ".post; // print the value scaled to the range [0,1] a.value.postln; // print the actual value a.input_(1.0.rand); // select a new value at random // the weighting of values will conform to the warp // with \exp, values fall uniformly in each octave wait(0.1); }) }).play(AppClock) )

Patterns

Within a pattern definition, a CV can directly substitute for a Pattern:( SynthDescLib.global.read; Pbind( \instrument, \default, \freq, a, \db, b, \dur, 0.2 ).play(quant: 0); )

Pfunc can be used to change the CV from within a Pattern.( SynthDescLib.global.read; Pbind( \instrument, \default, \freq, Pwhite(100, 1000).round(100), \placeholder, Pfunc({ arg ev; a.value_(ev.at(\freq)) }), \db, b, \dur, 0.2 ).play; )

CVs and external input

The input_(in) method makes it easy to connect a CV to any control source:( // MIDI MIDIClient.init; MIDIIn.connect(0,0); MIDIIn.control = { arg src, chan, num, val; a.input_(val/127) } )

The methods input and input_ are also used by ConductorPreset to allow interpolations between settings that follow warp of the CV's ControlSpec.