Created
October 26, 2011 05:01
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quasicrystals in Go (see http://mainisusuallyafunction.blogspot.com/2011/10/quasicrystals-as-sums-of-waves-in-plane.html for inspiration)
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| package main | |
| import ( | |
| "fmt" | |
| "flag" | |
| "image" | |
| "image/png" | |
| "math" | |
| "os" | |
| ) | |
| // generate a value for a wave (with orientation theta) at point x,y | |
| func wave(x float64, y float64, theta float64, stripes float64, size float64, offset float64) float64 { | |
| cth := math.Cos(theta) | |
| sth := math.Sin(theta) | |
| scale := 2 * math.Pi * stripes / size | |
| return (math.Cos((cth * x + sth * y) * scale + offset) + 1) / 2 | |
| } | |
| func main() { | |
| _k := flag.Int("k", 4, "The number of waves traveling in different directions") | |
| _stripes := flag.Int("stripes", 25, "The number of stripes per wave") | |
| size := flag.Int("size", 800, "The image size in pixels") | |
| log := flag.Bool("log", false, "Whether to stretch the image in a log-polar fashion") | |
| _offset := flag.Float64("offset", 0, "Offset (make the wave travel)") | |
| steps := flag.Int("steps", 1, "How many steps to the offset") | |
| nice := flag.Bool("nice", true, "Make a nice plasma effect") | |
| hard := flag.Bool("hard", false, "Filter a high contrast hard edge on the pattern") | |
| flag.Parse() | |
| k := float64(*_k) | |
| stripes := float64(*_stripes) | |
| img := image.NewRGBA(*size, *size) | |
| for step := 1; step <= *steps; step++ { | |
| offset := (*_offset) * float64(step) / float64(*steps) | |
| for i := 0; i < *size; i++ { | |
| for j := 0; j < *size; j++ { | |
| // cartesian coordinates | |
| x := float64(j - *size / 2) | |
| y := float64(i - *size / 2) | |
| // log-polar coordinates | |
| theta := math.Atan2(y, x) | |
| r := math.Log(math.Sqrt(x * x + y * y)) | |
| C := 0.0 // accumulator | |
| for t := 0.0; t < math.Pi; t += math.Pi / float64(k) { | |
| if *log { | |
| C += math.Cos((theta * math.Cos(t) + r * math.Sin(t)) * stripes ) | |
| } else { | |
| C += wave(x, y, t, stripes, float64(*size), offset) | |
| } | |
| } | |
| // convert result to 0-255 range | |
| c := uint8(0) | |
| if *nice { | |
| v := math.Fmod(C, 1) | |
| _k := C - v | |
| if int(_k) & 1 == 0 { | |
| c = uint8(v * 255) | |
| } else { | |
| c = uint8((1 - v) * 255) | |
| } | |
| } else { | |
| c = uint8((C + k) / (k * 2) * 255) | |
| } | |
| // create a hard edge | |
| if *hard { | |
| if c > 128 { | |
| c = 255 | |
| } else { | |
| c = 0 | |
| } | |
| } | |
| img.Set(i, j, image.RGBAColor{c, c, c, 255}) | |
| } | |
| } | |
| file, _ := os.Create(fmt.Sprintf("test%d.png", step)) | |
| png.Encode(file, img) | |
| file.Close() | |
| } | |
| } |
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