BPM-based sound trigger

BPM Counter / step sequencer

http://forum.unity3d.com/threads/133329-BPM-Counter-step-sequencer

Posted: 08:14 AM 04-23-2012

I've just cobbled together a very basic BPM-based sound trigger / sequencer.

Attach the script to an object with an audiosource (preferably a drum sound - kick, snare, hat) and in the inspector you can set the BPM, the notes on/off pattern, and the step size.

I've tried a few 4/4 combos around 120 bpm and it seems ok, though I suspect the timing is not as tight as it could be.

Is there a better method for solid timing than calling InvokeRepeating?

Code:  

#pragma strict
#pragma implicit
#pragma downcast
 
var BPM : float = 120.0;
private var t : float = 0.0;
var beatgrid : int[]; // in inspector assign 0/1 for beat on/off on individual step
private var beatmarker : int=0;
var steps : int = 4;
 
function Start(){
    
    t = BPM/60.0; // how many beats per second  
    t=(1.0/t)/steps; // divide by steps
    beatmarker=0;
    InvokeRepeating("Trigger",0,t);
}
 
 
function Trigger () {
    
    if (beatgrid[beatmarker]==1)audio.Play();
    beatmarker+=1;
    if (beatmarker>beatgrid.length-1)beatmarker=0;
}

Feel free to use / modify :-)