Imports System.Text

Imports System.Collections.Generic

Imports csound6netlib

Partial Public Class Examples

' Example 5 - Generating a Score, VB Try/Catch blocks

' In this example, we will look at three techniques for generating our Score.

' The first is one we have already seen, which is to just write out the score

' by hand as a String.

' Knowing that we pass strings into Csound to pass note events, we can also

' generate the string. In the second example, the score starts as an empty string.

' Using a for-loop, we append to sco note strings using a string formatting

' string that has its replacement values replaced. The replace values are

' calculated using the i value, and the result is an ascending note line.

' In the final example, we are going to generate a list of lists. The top-level

' list represents our score as a whole, and each sub-list within it represents

' the data for a single note. The main list is then processed in two ways: first,

' it processes each sub-list and joins the values together into a single note string;

' second, it joins each individual note string into a single, large score string,

' separated by newlines. The end result is a sequence of 13 notes with random

' pitches.

' The final example represents a common pattern of development. For systems that

' employ some event-based model of music, it is common to use some kind of data

' structure to represent events. This may use some kind of common data structure

' like a list, or it may be represented by using a class and instances of that

' class.

' Note, the three examples here are indicated within case statement. To listen to the examples,

' use a real number when selecting Example 5: 5.0 for the single note, 5.1 for the

' chromatic scale and 5.2 for random pitches.

Public Sub Example5(algorithm As Integer)

Dim sco As New StringBuilder

'Choose one of 3 ways to create a score: sequential pitches, random pitches, or hard-coded

Select Case algorithm 'integer between 0 and 2

Case 1

For i = 0 To 12

sco.AppendLine(String.Format("i1 {0} .25 0.5 8.{1:00}", (i * 0.25), i))

Next i

Case 2

Dim vals = New List(Of Double()) 'initialize a list to hold lists of doubles

Dim r = New Random()

For i = 0 To 12 'populate that list with note parameters (pitch is random number from 0 to 14

vals.Add(New Double() {i * 0.25, 0.25, 0.5, r.Next(15)})

Next i

' convert list of lists into a list of strings with random frequencys

For Each val As Double() In vals

sco.AppendLine(String.Format("i1 {0} {1} {2} 8.{3:00}", val(0), val(1), val(2), CInt(val(3))))

Next val

Case Else

sco.AppendLine("i1 0 1 0.5 8.00")

End Select

' Once a score string has been algorithmically assembled, do the usual csound loop.

' This time, we'll let C# Exceptions (try/catch) handle testing status for us.

' By catching the exception, we are assured exiting the "using" block

' and thereby disposing of csound and its memory correctly.

Using c As New Csound6Net

c.SetOutputDac(0) ' Set realtime output

Try

c.CompileOrc(orc2) ' Compile different Orchestra with moogladder

c.ReadScore(sco.ToString()) ' Read in score as built above

c.Start() ' When compiling from strings, this call needed before performing

While c.PerformKsmps() = False 'Play score until csound says it is over

End While

c.Stop()

Catch ex As Csound6NetException

Console.WriteLine(ex.Message)

End Try

End Using

End Sub

'Used in examples 5 and 6

Public Const orc2 = "sr=44100" & vbCrLf & _

"ksmps=32" & vbCrLf & _

"nchnls=2" & vbCrLf & _

"0dbfs=1" & vbCrLf & _

"instr 1 " & vbCrLf & _

"ipch = cps2pch(p5, 12)" & vbCrLf & _

"kenv linsegr 0, .05, 1, .05, .7, .4, 0" & vbCrLf & _

"aout vco2 p4 * kenv, ipch" & vbCrLf & _

"aout moogladder aout, 2000, 0.25" & vbCrLf & _

"outs aout, aout" & vbCrLf & _

"endin"

End Class