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