B4J Question Sound generator: 2 channels

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    
    Dim NumGenerators As Int = 3    'in for a penny, in for a pound
    Dim NumChannels As Int = 2    'left = 0, right = 1
    
    Dim Frequency(NumGenerators) As Float    'Hz
    Dim Level(NumGenerators, NumChannels) As Int    '0 to 100%
    Dim Phase(NumGenerators, NumChannels) As Float    '0 to 360 degrees
    
    Dim PhaseAccumulator(NumGenerators) As Int    'binary fixed-point 16.16
    Dim PhaseIncrement(NumGenerators) As Int    'binary fixed-point 16.16
    Dim PhaseShift(NumGenerators, NumChannels) As Int    'binary fixed-point 16.16
    
    Dim WaveTableSize As Int = 256    'power of 2
    Dim WaveTableIndexMask As Int = WaveTableSize - 1    '0b11111111
    
    Dim WaveTables(NumGenerators) As Object    'pretty sure that Android audio uses signed 16-bit samples
    
    Dim SampleRate As Int = 44100    '30 frames/second x 490 lines/frame x 3 samples/line

    Dim Streamer As AudioStreamer
    
End Sub

Sub MakeSineWaveTable(NumSamples As Int) As Short()

    Dim S(NumSamples) As Short

    For I = 0 To NumSamples - 1
        Dim Angle As Float = I * 2 * cPI / NumSamples
        Dim Sample As Float = Sin(Angle) * 32768
        If Sample < -32768 Then
            Sample = -32768
        else if Sample > 32767 Then
            Sample = 32767
        End If
        
        S(I) = Sample
    Next
    
    Return S
    
End Sub

Sub UpdateGeneratorParameters(Generator As Int)
    
    PhaseIncrement(Generator) = FrequencyToPhaseIncrement(Frequency(Generator))
    For C = 0 To NumChannels - 1
        PhaseShift(Generator, C) = PhaseToPhaseShift(Phase(Generator, C))
    Next
    
End Sub


Sub FrequencyToPhaseIncrement(Hertz As Float) As Int

    Return Hertz / SampleRate * WaveTableSize * 0x10000 + 0.5   'amount to increment phase accumulator by each sample time
    
End Sub


Sub PhaseToPhaseShift(Degrees As Float) As Int

    Return Degrees / 360 * WaveTableSize * 0x10000 + 0.5

End Sub

Sub GenerateSamples(NumSamples As Int) As Short()

    Dim S(NumChannels * NumSamples) As Short
    
    Dim SP As Int = 0
    
    Dim TotalChannelSample(NumChannels) As Int
    For I = 1 To NumSamples
        For C = 0 To NumChannels - 1
            TotalChannelSample(C) = 0
        Next
        
        For G = 0 To NumGenerators - 1
            Dim WaveTable() As Short = WaveTables(G)    'cast from object wtf
            
            PhaseAccumulator(G) = Bit.And(PhaseAccumulator(G) + PhaseIncrement(G), 0x3FFFFFFF)    'clear high two bits to avoid Int overflow
            
            For C = 0 To NumChannels - 1
                Dim WaveTableIndex As Int = Bit.ShiftRight(PhaseAccumulator(G) + PhaseShift(G, C), 16)
                Dim WaveSample As Int = WaveTable(Bit.And(WaveTableIndex, WaveTableIndexMask))
                Dim ChannelSample As Int = (WaveSample * Level(G, C) + 50) / 100
                TotalChannelSample(C) = TotalChannelSample(C) + ChannelSample
            Next
        Next
        
        For C = 0 To NumChannels - 1
            Dim Temp As Int = TotalChannelSample(C)
            If Temp < -32768 Then
                Temp = -32768
            else if Temp > 32767 Then
                Temp = 32767
            End If
            
            S(SP) = Temp
            SP = SP + 1    'interleaved channel eg 5.1 = 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5
        Next
    Next
    
    Return S
    
End Sub

Sub Activity_Create(FirstTime As Boolean)

    WaveTables(0) = MakeSineWaveTable(WaveTableSize)    'could do in loop
    WaveTables(1) = MakeSineWaveTable(WaveTableSize)    'but maybe one day might have
    WaveTables(2) = MakeSineWaveTable(WaveTableSize)    'different waveform for each channel

    'default Level and Phase parameters aka Captain Lazy Strikes Again
    For G = 0 To NumGenerators - 1
        For C = 0 To NumChannels - 1
            Level(G, C) = 0
            Phase(G, C) = 0
        Next
    Next

    Frequency(0) = 440
    Level(0, 0) = 30
    
    Frequency(1) = 439
    Level(1, 1) = 20
    
    Frequency(2) = 438
    Level(2, 0) = 10
    
    For G = 0 To NumGenerators - 1   
        UpdateGeneratorParameters(G)
    Next

    Streamer.Initialize("streamer", 44100, False, 16, Streamer.VOLUME_MUSIC)
    
    Streamer.StartPlaying
    
    Dim bc As ByteConverter
    bc.LittleEndian = True
    
    For TenthOfSecond = 1 To 100    '10 seconds
        Dim S() As Short = GenerateSamples(SampleRate / 10)
        Log(Streamer.Write(bc.ShortsToBytes(S)))
    Next
    
    Streamer.Write(Null) 'when this "message" will be processed, the player will stop.
    
End Sub