Unity3D

BPM-based sound trigger

일등하이 2012. 9. 18. 10:52
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BPM Counter / step sequencer





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:  
  1. #pragma strict
    2. 

  2. #pragma implicit
    3. 

  3. #pragma downcast
    4. 

  4.  
    5. 

  5. var BPM : float = 120.0;
    6. 

  6. private var t : float = 0.0;
    7. 

  7. var beatgrid : int[]; // in inspector assign 0/1 for beat on/off on individual step
    8. 

  8. private var beatmarker : int=0;
    9. 

  9. var steps : int = 4;
    10. 

  10.  
    11. 

  11. function Start(){
    12. 

  12.     
    13. 

  13.     t = BPM/60.0; // how many beats per second  
    14. 

  14.     t=(1.0/t)/steps; // divide by steps
    15. 

  15.     beatmarker=0;
    16. 

  16.     InvokeRepeating("Trigger",0,t);
    17. 

  17. }
    18. 

  18.  
    19. 

  19.  
    20. 

  20. function Trigger () {
    21. 

  21.     
    22. 

  22.     if (beatgrid[beatmarker]==1)audio.Play();
    23. 

  23.     beatmarker+=1;
    24. 

  24.     if (beatmarker>beatgrid.length-1)beatmarker=0;
    25. 

  25. }

Feel free to use / modify :-)

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