fractals.go

package main

import (
	"fmt"
	"github.com/fogleman/gg"
	"math/rand"
)

func randomFromDistribution(distribution []float64) int {
	randFloat := rand.Float64()

	sum := 0.0

	for i := range distribution {
		sum += distribution[i]
		if randFloat <= sum {
			return i
		}
	}

	return 0
}

func calcNextPoint(point [2]float64) [2]float64 {
	funcSet := [][7]float64{
		[7]float64{0.000, 0.000, 0.000, 0.600, 0.00, -0.065, 0.1},
		[7]float64{0.440, 0.000, 0.000, 0.550, 0.00, 0.200, 0.18},
		[7]float64{0.343, -0.248, 0.199, 0.429, -0.03, 0.100, 0.18},
		[7]float64{0.343, 0.248, -0.199, 0.429, 0.03, 0.100, 0.18},
		[7]float64{0.280, -0.350, 0.280, 0.350, -0.05, 0.000, 0.18},
		[7]float64{0.280, 0.350, -0.280, 0.350, 0.05, 0.000, 0.18},
	}

	distribution := make([]float64, len(funcSet))

	for i := range funcSet {
		distribution[i] = funcSet[i][6]
	}

	funcToUse := funcSet[randomFromDistribution(distribution)]

	return [2]float64{
		funcToUse[0]*point[0] + funcToUse[1]*point[1] + funcToUse[4],
		funcToUse[2]*point[0] + funcToUse[3]*point[1] + funcToUse[5],
	}
}

func main() {
	dc := gg.NewContext(1000, 1000)
	dc.SetRGB(0, 0, 0)
	dc.InvertY()

	currentPoint := [2]float64{1.0, 1.0}

	for i := 0; i <= 100000; i++ {
		dc.Push()
		fmt.Printf("%d -> (%f,%f)\n", i, currentPoint[0], currentPoint[1])
		dc.DrawPoint(currentPoint[0]*1000+500, currentPoint[1]*1000+500, 1.0)
		dc.Fill()
		currentPoint = calcNextPoint(currentPoint)
		dc.Pop()
	}

	dc.SavePNG("output.png")
}