Mandelbrot init

mandelbrot/server/main.go

@@ -0,0 +1,102 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"net/url"
+	"strconv"
+
+	"github.com/lucasb-eyer/go-colorful"
+)
+
+type Mandelbrot []uint
+
+func (m Mandelbrot) SetPixel(width int, x int, y int, color []uint) {
+	start := y*int(width)*4 + x*4
+	for i := 0; i < 4; i++ {
+		m[start+i] = color[i]
+	}
+}
+
+func GetColor(iteration uint, maxIterations uint) []uint {
+	c := colorful.Hsl(float64(iteration)/256, 1.0, float64(iteration)/(float64(iteration)+8.0))
+	return []uint{
+		uint(c.R * 255),
+		uint(c.G * 255),
+		uint(c.B * 255),
+		255,
+	}
+	//return []uint{0, 0, 0, 255}
+}
+
+func CalculateMandelbrot(maxIterations uint, minX float64, minY float64, maxX float64, maxY float64, width int, height int) Mandelbrot {
+	mandelbrot := make(Mandelbrot, width*height*4)
+
+	dx := maxX - minX
+	dy := maxY - minY
+	for row := 0; row < height; row++ {
+		for col := 0; col < width; col++ {
+			cRe := (float64(col)*dx)/float64(width) + minX
+			cIm := (float64(row)*dy)/float64(height) + minY
+
+			var x float64
+			var y float64
+
+			var iteration uint
+			for ; x*x+y*y <= 4 && iteration < maxIterations; iteration++ {
+				newX := x*x - y*y + cRe
+				y = 2*x*y + cIm
+				x = newX
+			}
+
+			mandelbrot.SetPixel(width, col, row, GetColor(iteration, maxIterations))
+		}
+	}
+
+	return mandelbrot
+}
+
+func GetFloatParameter(query url.Values, name string, defaultValue float64) float64 {
+	if str := query.Get(name); len(str) > 0 {
+		value, err := strconv.ParseFloat(str, 64)
+		if err == nil {
+			return value
+		}
+	}
+	return defaultValue
+}
+
+func GetIntParameter(query url.Values, name string, defaultValue int) int {
+	if str := query.Get(name); len(str) > 0 {
+		value, err := strconv.ParseInt(str, 10, 64)
+		if err == nil {
+			return int(value)
+		}
+	}
+	return defaultValue
+}
+
+func MainHandler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+
+	query := r.URL.Query()
+
+	var maxIterations uint = 1000
+	minX := GetFloatParameter(query, "minX", -2.0)
+	minY := GetFloatParameter(query, "minY", -2.0)
+	maxX := GetFloatParameter(query, "maxX", 2.0)
+	maxY := GetFloatParameter(query, "maxY", 2.0)
+	width := GetIntParameter(query, "width", 1000)
+	height := GetIntParameter(query, "height", 1000)
+
+	log.Println(minX, minY, maxX, maxY, width, height)
+
+	json.NewEncoder(w).Encode(CalculateMandelbrot(maxIterations, minX, minY, maxX, maxY, width, height))
+}
+
+func main() {
+	http.HandleFunc("/", MainHandler)
+
+	log.Fatal(http.ListenAndServe(":8001", nil))
+}