50 lines
920 B
Go
50 lines
920 B
Go
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// Lisajous generates GIF animations of random Lisajous figures.
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package main
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import (
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"image"
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"image/color"
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"image/gif"
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"io"
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"math"
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"math/rand"
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"os"
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)
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var palette = [] color.Color{color.White, color.Black}
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const (
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whiteIndex = 0
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blackindex = 1
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)
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func main() {
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lisajous(os.Stdout)
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}
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func lisajous(out io.Writer) {
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const (
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cycles = 5
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res = 0.001
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size = 100
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nframes = 64
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delay = 8
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)
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freq := rand.Float64() * 3.0
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anim := gif.GIF{LoopCount: nframes}
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phase := 0.0
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for i := 0; i < nframes; i++ {
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rect := image.Rect(0, 0, 2*size+1, 2*size+1)
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img := image.NewPaletted(rect, palette)
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for t := 0.0; t < cycles*2*math.Pi; t += res {
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x := math.Sin(t)
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y := math.Sin(t*freq + phase)
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img.SetColorIndex(size+int(x*size+0.5), size+int(y*size+0.5), blackindex)
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}
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phase += 0.1
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anim.Delay = append(anim.Delay, delay)
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anim.Image = append(anim.Image, img)
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}
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gif.EncodeAll(out, &anim)
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}
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