Been messing around with FMOD for C# game development and I've hit a snag early on that I can't seem to get around. I want to do some branching audio stuff and sync some gameplay action to beats and such, so I've tried adding syncpoints to my music tracks. Here's code:
public class Music
{
private Sound music;
private Channel channel;
private IntPtr syncPtr;
public string File { get; private set; }
public Music(string file)
{
File = file;
}
public void Load()
{
music = new Sound();
Audio.System.createSound(File, MODE.HARDWARE, ref music);
}
public void Unload()
{
music.release();
}
public virtual void Play()
{
Audio.System.playSound(channel == null ? CHANNELINDEX.FREE : CHANNELINDEX.REUSE, music, false, ref channel);
music.addSyncPoint(500, TIMEUNIT.MS, "wooo", ref syncPtr);
channel.setCallback(channelCallback);
}
private RESULT channelCallback(IntPtr channelraw, CHANNEL_CALLBACKTYPE type, IntPtr commanddata1, IntPtr commanddata2)
{
if (type == CHANNEL_CALLBACKTYPE.SYNCPOINT)
Console.WriteLine("sync!");
return RESULT.OK;
}
}
And then...
m = new Music(MUS_TUTORIAL); //m is static
m.Load();
m.Play();
The song loads and plays fine... until it hits that 500ms syncpoint I added. At this point, VC# spits out the following error from within FMOD.EventSystem.update():
A callback was made on a garbage collected delegate of type 'Game!FMOD.CHANNEL_CALLBACK::Invoke'. This may cause application crashes, corruption and data loss. When passing delegates to unmanaged code, they must be kept alive by the managed application until it is guaranteed that they will never be called.
So somehow FMOD is losing track of the delegate I passed it. The Music instance that holds the delegate has not been garbage collected - I'm storing it in a static variable for now - but I've tried with a static method too to no avail. If I disable the CallbackOnCollectedDelegate MDA the error becomes a null reference exception, so the MDA isn't mistaken. I assume I must just not fully understand what FMOD is doing here.
Are any C# + FMOD gurus able to see my mistake?