music - waves.go

     1  package music
     2  
     3  import "math"
     4  
     5  type Wave func(phase float64) float64
     6  
     7  func (n Note) Saw(phase float64) float64 {
     8  	_, frac := math.Modf(float64(n) * phase)
     9  	return frac*2 - 1
    10  }
    11  
    12  func (n Note) Sine(phase float64) float64 {
    13  	_, frac := math.Modf(float64(n) * phase)
    14  	return math.Sin(2 * math.Pi * frac)
    15  }
    16  func (n Note) Square(phase float64) float64 {
    17  	_, frac := math.Modf(float64(n) * phase)
    18  	if frac > 0.5 {
    19  		return 1
    20  	}
    21  	return -1
    22  }
    23  
    24  func (n Note) Triangle(phase float64) float64 {
    25  	_, frac := math.Modf(float64(n) * phase)
    26  	if frac < 0.5 {
    27  		return 4*frac - 1
    28  	}
    29  	return 3 - 4*frac
    30  }