Add mandelbrot Golang with webassembly
This commit is contained in:
kingofdog
241
mandelbrot-webassembly/server/main.go
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241
mandelbrot-webassembly/server/main.go
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@@ -0,0 +1,241 @@
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package main
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import (
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"fmt"
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"math"
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"syscall/js"
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)
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type selection struct {
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startX int
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startY int
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endX int
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endY int
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}
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type mbRender struct {
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doc js.Value
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ctx js.Value
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backCtx []js.Value
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curCtx int
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width float64
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height float64
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minX float64
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minY float64
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maxX float64
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maxY float64
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colorMode string
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imageData js.Value
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mandelbrot chan Mandelbrot
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mandelbrotValue Mandelbrot
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mandelbrotProgress chan float64
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mandelbrotProgressValue float64
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mouseDown bool
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hasSelection bool
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selection selection
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}
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type Mandelbrot []byte
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func (mb *mbRender) getMandelbrot(maxIterations uint) {
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go func() {
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mb.mandelbrot <- mb.CalculateMandelbrot(maxIterations)
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}()
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}
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func (mb *mbRender) start() {
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mb.doc = js.Global().Get("document")
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canvasEl := mb.doc.Call("getElementById", "canvas")
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//mb.width = mb.doc.Get("body").Get("clientWidth").Float()
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//mb.height = mb.doc.Get("body").Get("clientHeight").Float()
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mb.width = 1000.0
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mb.height = 1000.0
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mb.minX = -2.0
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mb.minY = -2.0
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mb.maxX = 2
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mb.maxY = 2
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canvasEl.Set("width", mb.width)
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canvasEl.Set("height", mb.height)
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mb.ctx = canvasEl.Call("getContext", "2d")
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mb.imageData = mb.ctx.Call("getImageData", 0, 0, mb.width, mb.height)
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mb.mandelbrot = make(chan Mandelbrot)
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mb.getMandelbrot(1000)
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mouseDownEvt := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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evt := args[0]
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mb.mouseDown = true
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mb.hasSelection = true
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mb.selection = selection{
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startX: evt.Get("clientX").Int() - canvasEl.Get("offsetLeft").Int(),
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startY: evt.Get("clientY").Int() - canvasEl.Get("offsetTop").Int(),
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endX: evt.Get("clientX").Int() - canvasEl.Get("offsetLeft").Int(),
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endY: evt.Get("clientY").Int() - canvasEl.Get("offsetTop").Int(),
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}
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return nil
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})
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defer mouseDownEvt.Release()
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mouseMoveEvt := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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evt := args[0]
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if mb.mouseDown {
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posX := evt.Get("clientX").Int() - canvasEl.Get("offsetLeft").Int()
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posY := evt.Get("clientY").Int() - canvasEl.Get("offsetTop").Int()
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dx := posX - mb.selection.startX
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dy := posY - mb.selection.startY
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if math.Abs(float64(dx)) > math.Abs(float64(dy)) {
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mb.selection.endX = mb.selection.startX + dx
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mb.selection.endY = mb.selection.startY + dx
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} else {
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mb.selection.endX = mb.selection.startX + dy
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mb.selection.endY = mb.selection.startY + dy
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}
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}
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return nil
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})
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defer mouseMoveEvt.Release()
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mouseUpEvt := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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mb.mouseDown = false
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mb.hasSelection = false
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newMinX := CalcReal(float64(mb.selection.startX), mb.width, mb.minX, mb.maxX)
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newMinY := CalcReal(float64(mb.selection.startY), mb.height, mb.minY, mb.maxY)
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newMaxX := CalcReal(float64(mb.selection.endX), mb.width, mb.minX, mb.maxX)
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newMaxY := CalcReal(float64(mb.selection.endY), mb.height, mb.minY, mb.maxY)
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mb.minX = newMinX
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mb.minY = newMinY
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mb.maxX = newMaxX
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mb.maxY = newMaxY
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mb.getMandelbrot(uint(math.Min(1000*1/math.Sqrt((mb.maxX-mb.minX)), 100000)))
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return nil
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})
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defer mouseUpEvt.Release()
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canvasEl.Call("addEventListener", "mousedown", mouseDownEvt)
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canvasEl.Call("addEventListener", "mousemove", mouseMoveEvt)
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canvasEl.Call("addEventListener", "mouseup", mouseUpEvt)
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var renderFrame js.Func
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renderFrame = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
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// mb.ctx.Call("clearRect", 0, 0, mb.width, mb.height)
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select {
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case x, ok := <-mb.mandelbrot:
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if ok {
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mb.mandelbrotValue = x
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}
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default:
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}
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select {
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case x, ok := <-mb.mandelbrotProgress:
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if ok {
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mb.mandelbrotProgressValue = x
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}
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default:
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}
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value := js.Global().Get("Uint8Array").New(len(mb.mandelbrotValue))
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js.CopyBytesToJS(value, mb.mandelbrotValue)
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mb.imageData.Get("data").Call("set", value)
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mb.ctx.Call("putImageData", mb.imageData, 0, 0)
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if mb.hasSelection {
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mb.ctx.Set("fillStyle", "rgba(0, 0, 255, 0.8)")
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mb.ctx.Call("fillRect", mb.selection.startX, mb.selection.startY, mb.selection.endX-mb.selection.startX, mb.selection.endY-mb.selection.startY)
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}
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js.Global().Call("requestAnimationFrame", renderFrame)
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return nil
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})
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done := make(chan struct{}, 0)
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js.Global().Call("requestAnimationFrame", renderFrame)
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<-done
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}
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func (m Mandelbrot) SetPixel(width int, x int, y int, color []byte) {
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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 (mb mbRender) GetColor(iteration uint, maxIterations uint) []byte {
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intensity := (math.Pi / 2.0) * float64(iteration) / float64(maxIterations)
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return []byte{
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byte(math.Sin(intensity) * 256),
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byte(math.Sin(intensity*2) * 256),
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byte(math.Cos(intensity) * 256),
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255,
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}
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// HSL - red
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/*c := colorful.Hsl(float64(iteration)/256, 1.0, float64(iteration)/(float64(iteration)+8.0))
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return []byte{
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byte(c.R * 255),
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byte(c.G * 255),
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byte(c.B * 255),
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255,
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}*/
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}
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func CalcReal(x, width, minX, maxX float64) float64 {
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return (x*(maxX-minX))/width + minX
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}
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func CalcImaginary(y, height, minY, maxY float64) float64 {
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return (y*(maxY-minY))/height + minY
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}
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func (mb *mbRender) CalculateMandelbrot(maxIterations uint) Mandelbrot {
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fmt.Println("max iterations", maxIterations)
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mandelbrot := make(Mandelbrot, int(mb.width*mb.height*4))
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mb.mandelbrotProgress = make(chan float64)
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for row := 0; row < int(mb.height); row++ {
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for col := 0; col < int(mb.width); col++ {
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cRe := CalcReal(float64(col), mb.width, mb.minX, mb.maxX)
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cIm := CalcImaginary(float64(row), mb.height, mb.minY, mb.maxY)
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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(int(mb.width), col, row, mb.GetColor(iteration, maxIterations))
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}
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go func() {
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mb.mandelbrotProgress <- float64(row) / mb.height
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}()
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}
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return mandelbrot
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}
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func main() {
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fmt.Println("Hallo fögel")
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mb := mbRender{}
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mb.start()
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}
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