b.go

var concurrencyLevel = flag.Int("c", 20, "concurrency level")

func main() {
  flag.Parse()
	sem = make(chan bool, *concurrencyLevel)
//  ...
//  ...
//  ...
}

func renderImage() {
	for i := 0; i < imHeight; i++ {
		for j := 0; j < imWidth; j++ {
			plotPixel(complex(float64(i), float64(j)))
			currentPixel++
		}
	}

	for i := 0; i < cap(sem); i++ {
		sem <- true
	}
}


// check if c belongs to set, assign color accordingly and plot
func plotPixel(c complex128) {
	sem <- true

	switch *coloringMethod {
	case "ml":
		go func(c complex128) {
			res := getColorFromMLMandelbrot(c)
			<-sem
			plot(res.C, res.Color)
		}(c)
	case "classic":
		go func(c complex128) {
			res := getColorFromClassicMandelbrot(c)
			<-sem
			plot(res.C, res.Color)
		}(c)
	}
}