Why does this Playsound code fail?

BlitzMax Forums/BlitzMax Programming/Why does this Playsound code fail?

Grey Alien

(Posted 2006) [#1]

Hiya, the code below runs but no sound is made when space is pressed.

If you change the playsound to be PlaySound(Bang) i.e not using a channel it's fine, except you get many of the same sound on different channels.

If you change the play sound to be ChannelBang = PlaySound(Bang) it works, but aren't I just making a new TChannel eveytime Space is pressed and isn't this wasteful?

Finally, if you change the play sound to be ChannelBang = PlaySound(Bang,ChannelBang), the first time you press space there is no sound! Then it works after that. Note that the channel is reused so you do not get many of the same sound.

What's going on?

All I can guess is that the channel made at the start with New is somehow not set or ready to play sounds and needs to be configured first somehow, but how?

Thanks in advance for any info.

Graphics 800,600,0

'test variables
Global Bang:TSound = LoadSound("explosion.wav",False)
Global ChannelBang:TChannel = New TChannel

Repeat
	Cls
	If KeyHit(KEY_SPACE) Then
		PlaySound(Bang,ChannelBang)
	EndIf
	Flip
Until KeyHit(KEY_ESCAPE)

ziggy

(Posted 2006) [#2]

To avoid this, I always create the Bank when the sound needs to be played. I don't know if it's the best way to do it, but it works.


Graphics 800,600,0

'test variables
Global Bang:TSound = LoadSound("explosion.wav",False)
Global ChannelBang:TChannel

Repeat
        Cls
        If KeyHit(KEY_SPACE) Then
                if channelbang = null then
                         channelbang = PlaySound(Bang)
                else
                         if channelbang.IsPlaying() then channelbang.Stop()
                          channelbang = PlaySound(Bang)
                endIf
        EndIf
        Flip
Until KeyHit(KEY_ESCAPE)

Grey Alien

(Posted 2006) [#3]

yeah OK, thanks, that's a good method. Still don't understand why my method doesn't work.

Also everytime Playsound is called, whatever channelband was pointing at is still in the memory. This would be a memory hole in a language without auto garbage collection, so when exactly does Max decide to clean up these channels? As soon as the sound stops playing, never?

ziggy

(Posted 2006) [#4]

I don't know... good question...

degac

(Posted 2006) [#5]

I think the error is in the following line

Global ChannelBang:TChannel =New TChannel

It should be

Global ChannelBang:TChannel = AllocChannel()

Grey Alien

(Posted 2006) [#6]

aha now that's interestijg, I'll try it out. Thanks!