Help needed from VB expert !

**CdRsKuLL** · 12-27-2004, 01:19 PM

taken up learning VB, just for the fun of it.. I'm trying to write a BMW i-bus steering wheel interface, that maps buttons to different apps and stuff.

I'm doing ok, but can seem to grasp the API master volume control. I've been searching and searching and trying different code but failed to get anywhere with this section of the code.. in brief I want to adjust the master vol up and down and also mute it..

So far what I have pieced together is the below code, but then I click on my up / down buttons I would expect the master volume slider to move on the windows mixer but it doesnt.. can anyone please advise what the hell i'm doing wrong.

Code:

Option Explicit

'Types
    Private Type tVolume
        Volume As Long
    End Type
    
    Private Type tVolumeEx
        vLeft As Integer
        vRight As Integer
    End Type

'Declares
    Private Declare Function waveOutGetVolume Lib "winmm.dll" _
        (ByVal uDeviceID As Long, lpdwVolume As Long) As Long
    Private Declare Function waveOutSetVolume Lib "winmm.dll" _
        (ByVal uDeviceID As Long, ByVal dwVolume As Long) As Long
Sub ChangeVolume(iValue As Single)
    Dim DeviceID As Long
    
    Dim ActVolume As Long
    
    Dim Vol As tVolume
    Dim VolSplit As tVolumeEx
    
    'The wave level
    DeviceID = -0
    
    'Get current volume
    waveOutGetVolume DeviceID, ActVolume
    Vol.Volume = ActVolume
    
    'Split to stereo channels
    '(Long >> 2x Int)
    LSet VolSplit = Vol
    
    'Change volume
    VolSplit.vLeft = VolSplit.vLeft + iValue
    VolSplit.vRight = VolSplit.vRight + iValue
    
    'Combine back to one variable
    '(2x Int >> Long)
    LSet Vol = VolSplit
    
    'Apply new volume
    ActVolume = Vol.Volume
    waveOutSetVolume DeviceID, ActVolume
End Sub


Private Sub cmdDecrease_Click()
    ChangeVolume -2048
End Sub

Private Sub cmdIncrease_Click()
    ChangeVolume 2048
End Sub

cheers in advance
CdRsKuLL

**Peoples** · 12-27-2004, 01:38 PM

I dont know if this is the smartest move
VolSplit.vLeft = VolSplit.vLeft + iValue
VolSplit.vRight = VolSplit.vRight + iValue
because you dont know the current states of the vleft and vright, one could be overflowing positivly and the other can be overflowing negitively..... I would bypass this completly

Code:

Option Explicit

'Types
    Private Type tVolume
        Volume As Long
    End Type
    
    Private Type tVolumeEx
        vLeft As Integer
        vRight As Integer
    End Type

'Declares
    Private Declare Function waveOutGetVolume Lib "winmm.dll" _
        (ByVal uDeviceID As Long, lpdwVolume As Long) As Long
    Private Declare Function waveOutSetVolume Lib "winmm.dll" _
        (ByVal uDeviceID As Long, ByVal dwVolume As Long) As Long
Sub ChangeVolume(iValue As Single)
    Dim DeviceID As Long
    
    Dim ActVolume As Long
    
    Dim Vol As tVolume
    Dim VolSplit As tVolumeEx
    
    'The wave level
    DeviceID = -0
    
    'Get current volume
    waveOutGetVolume DeviceID, ActVolume
    Vol.Volume = ActVolume
    Label1.Caption = ActVolume
    'Split to stereo channels
    '(Long >> 2x Int)
    LSet VolSplit = Vol
    
    'Change volume
    
    
    
    
    
    
    
    
    ActVolume = ActVolume + iValue
    
    
    
    'Apply new volume
    
    waveOutSetVolume DeviceID, ActVolume
End Sub


Private Sub cmdDecrease_Click()
    ChangeVolume -2024
End Sub

Private Sub cmdIncrease_Click()
    ChangeVolume 2024
End Sub

This changes your WAV volume settings. But be careful because it seems that it will loop through max and min volume, so if you keep making it quieter eventually it will start back at the top.

I havent played with this stuff in a while, so i dont remember too much about the volume API calls, but this might help you a little bit.

**viguera** · 12-27-2004, 02:38 PM

Originally Posted by Peoples

I dont know if this is the smartest move
VolSplit.vLeft = VolSplit.vLeft + iValue
VolSplit.vRight = VolSplit.vRight + iValue
because you dont know the current states of the vleft and vright, one could be overflowing positivly and the other can be overflowing negitively..... I would bypass this completly

Actually VolSplit is set by the LSet, after the waveOutGetVolume. My guess is that this value is actually the problem... either ActVolume is not returning (probably from the external call failing?) or it has some weird value that returns after the call. Best bet would probably be some debugging msgbox calls in there to see what's happening, or stepping through the code at runtime and putting some watches in there to see what the values are.

For all intents and purposes it looks like it should work though...

Only other thing that I can think of is that he renamed the buttons or something... since the subs are tied to cmdDecrease and cmdIncrease.

* shrug *

**omar** · 12-27-2004, 04:14 PM

@CdrSkull,

This is quick and dirty. Use this code. To keep from looping, the actVOlume should be between 0 and 65535.

Code:

Sub ChangeVolume(iValue As Single)
    Dim DeviceID As Long
    
    Dim ActVolume As Long
    
    Dim Vol As tVolume
    Dim VolSplit As tVolumeEx
    
    'The wave level
    DeviceID = -0
    
    'Get current volume
     waveOutGetVolume DeviceID, ActVolume
    
    Vol.Volume = ActVolume
    Label1.Caption = Int(ActVolume)
    'Split to stereo channels
    '(Long >> 2x Int)
   LSet VolSplit = Vol
    
    'Change volume
    
    
    
    
    
    
    
    
    ActVolume = ActVolume + iValue
    
    If Int(ActVolume) > 65535 Then
     ActVolume = 65535
  ElseIf Int(ActVolume) < 0 Then
     ActVolume = 0
  Else
     ActVolume = ActVolume
  End If

    
    'Apply new volume
    
    waveOutSetVolume DeviceID, ActVolume
End Sub

**CdRsKuLL** · 12-27-2004, 04:28 PM

thanks fella's for your input.. yep the code does work, I was expecting the mixer to update when I press the buttons, but it doesnt. I needed to shut it and re open it to notice the changes..

Also as mentioned this alters the wav volume, but I was actual after altering the master volume.

What would I need to add/change to get it to show update in the mixer like other volume programs to in realtime rather then closing it and starting it up again, and map it to the main volume rather then the wave

cheers for all your help peeps..