music - visualise.go

     1  package music
     2  
     3  import (
     4  	"image/draw"
     5  
     6  	"vimagination.zapto.org/limage/lcolor"
     7  )
     8  
     9  var (
    10  	topLine    = lcolor.RGB{R: 255}
    11  	middleLine = lcolor.RGB{G: 255}
    12  	bottomLine = lcolor.RGB{B: 255}
    13  	point      = lcolor.RGB{}
    14  	between    = lcolor.RGB{R: 127, G: 127, B: 127}
    15  )
    16  
    17  func (p *Player) Visualise(im draw.Image, channels int) {
    18  	if channels < 1 {
    19  		return
    20  	}
    21  	b := im.Bounds()
    22  	n := b.Dx()
    23  	sounds := make([][]float32, channels)
    24  	for i := range sounds {
    25  		sounds[i] = make([]float32, n)
    26  	}
    27  	p.mu.Lock()
    28  	p.processMusic(sounds)
    29  	p.mu.Unlock()
    30  	channelHeight := b.Dy() / channels
    31  	top := 0
    32  	middle := channelHeight >> 1
    33  	bottom := channelHeight
    34  	for _, channel := range sounds {
    35  		x := b.Min.X
    36  		last := 0
    37  		for _, sample := range channel {
    38  			p := int(sample*float32(channelHeight>>1)) + middle
    39  			im.Set(x, top, topLine)
    40  			im.Set(x, middle, middleLine)
    41  			im.Set(x, bottom, bottomLine)
    42  			if last < p {
    43  				for i := last; i < p; i++ {
    44  					im.Set(x, i, between)
    45  				}
    46  			} else if last > p {
    47  				for i := last; i > p; i-- {
    48  					im.Set(x, i, between)
    49  				}
    50  			}
    51  			last = p
    52  			im.Set(x, p, point)
    53  			x++
    54  		}
    55  		top += channelHeight
    56  		middle += channelHeight
    57  		bottom += channelHeight
    58  	}
    59  }