JOBnik's Forum

BASS => VB Examples => Topic started by: ritmod on December 25, 2006, 06:32:32 PM

Title: customizing a size of spectrum analyzer ..
Post by: ritmod on December 25, 2006, 06:32:32 PM

sorry, my english is very bad...


hi. i referencee bass - spectrum code written by JOBnik

I have a problem with modifying the size of spectrum by this code
actually i also posted this problem to - Un4seen

the code is...

----------------------------------------------------------------------------------------------------------
Public Const SPECWIDTH As Long = 656 ' display width
Public Const SPECHEIGHT As Long = 500 ' height (changing requires palette adjustments too)

' MATH Functions
Public Function Sqrt(ByVal num As Double) As Double
    Sqrt = num ^ 0.5
End Function

Function Log10(ByVal X As Double) As Double
    Log10 = Log(X) / Log(10#)
End Function

' update the spectrum display - the interesting bit
Public Sub UpdateSpectrum(ByVal uTimerID As Long, ByVal uMsg As Long, ByVal dwUser As Long, ByVal dw1 As Long, ByVal dw2 As Long)
    Dim X As Long, Y As Long, y1 As Long
   
        Dim fft(1024) As Single     ' get the FFT data
        Call BASS_ChannelGetData(chan, fft(0), BASS_DATA_FFT2048)

           
#If 1 Then
                Y = Sqrt(fft(X + 1)) * 3 * SPECHEIGHT - 4 ' scale it (sqrt to make low values more visible)
             
#Else
              '  Y = fft(X + 1) * 10 * SPECHEIGHT ' scale it (linearly)
#End If
               
       If (specmode = 1) Then  ' logarithmic, acumulate & average bins
            ReDim specbuf(SPECWIDTH * (SPECHEIGHT + 1)) As Byte ' clear display             
            Dim b0 As Long
            b0 = 0
            BANDS = SPECWIDTH / 13
            frmSpectrum.Caption = BANDS
           
            Dim sc As Long, b1 As Long
            Dim sum As Single
            For X = 0 To BANDS - 1
                sum = 0
                b1 = 2 ^ (X * 10# / (BANDS - 1))
                If (b1 > 1023) Then b1 = 1023
                If (b1 <= b0) Then b1 = b0 + 1 ' make sure it uses at least 1 FFT bin
                sc = 10 + b1 - b0
                Do
                    sum = sum + fft(1 + b0)
                    b0 = b0 + 1
                Loop While b0 < b1
                Y = Sqrt(sum / Log10(sc)) * 3 * SPECHEIGHT - 4 ' scale it               
                If (Y > SPECHEIGHT) Then Y = SPECHEIGHT ' cap it
                Y = Y - 1
                While (Y >= 0)                           
               Call FillMemory(specbuf(Y * SPECWIDTH + X * 13), 13 - 2, Y + 1)

                    Y = Y - 1
                Wend
            Next X
       
           
        End If

    ' update the display
    ' to display in a PictureBox, simply change the .hDC to Picture1.hDC
       Call SetDIBitsToDevice(frmSpectrum.hDC, 0, 0, SPECWIDTH, SPECHEIGHT, 0, 0, 0, SPECHEIGHT, specbuf(0), bh, 0)
 --------------------------------------------------------------------------------------

code of frmspectrum
.
.
.
 With bh.bmiHeader
        .biBitCount = 8
        .biPlanes = 1
        .biSize = Len(bh.bmiHeader)
         .biWidth = specwidth           
               
        .biHeight = SPECHEIGHT  ' upside down (line 0=bottom)
        .biClrUsed = 256
        .biClrImportant = 256
    End With
.
.
.
------------------------------------------------------------------------
i modified the SPECWIDTH to 656 and  SPECHEIGHT to 500

but the spectrum was inclined (maybe ,if the value of specwidth was a multiple of 4 . it seems to be OK).
and overflow error was occured
how can i controll this problem ?
please let me know.
thanks.

Title: Re: customizing a size of spectrum analyzer ..
Post by: (: JOBnik! :) on December 26, 2006, 01:59:58 PM

Hi ;D

I'll check it out today a bit later :)

edit
Still didn't have time to check it... sorry.

Title: Re: customizing a size of spectrum analyzer ..
Post by: (: JOBnik! :) on December 28, 2006, 02:33:46 AM

Hi ;D

Sorry, I didn't have time to check it, but I see Ian has already posted a reply in BASS forum:
here's a link: http://www.un4seen.com/forum/?topic=6568.msg44103#msg44103

I didin't test it.

Title: Re: customizing a size of spectrum analyzer ..
Post by: ritmod on December 29, 2006, 08:19:54 AM

very thank you !! JOBnick!! ;)