畑政義写像

hata_map.go

package main

import (
	"math/cmplx"
	"image"
	"image/color"
	"image/png"
	"os"
)

var a = 0.0 + 0.0i
var b = 0.0 + 0.0i
var c = 0.0 + 0.0i
var d = 0.0 + 0.0i

const im_w = 1440
const im_h = 900
const vi_w = 2.0
const vi_h = vi_w / float64(im_w) * float64(im_h)

var img = image.NewRGBA(image.Rect(0, 0, im_w, im_h))

func f1 (z complex128) (complex128) {
	return a * z + b * cmplx.Conj(z)
}

func f2 (z complex128) (complex128) {
	return c * (z - 1) + d * (cmplx.Conj(z) - 1) + 1
}

func draw (z complex128, depth int) () {

	if (depth > 15) {
		return
	}

	z1 := f1(z)
	z2 := f2(z)

	x1 := int((real(z1) + (vi_w / 2)) / (vi_w / float64(im_w)))
	y1 := int((imag(z1) + (vi_h / 2)) / (vi_h / float64(im_h)))
	x2 := int((real(z2) + (vi_w / 2)) / (vi_w / float64(im_w)))
	y2 := int((imag(z2) + (vi_h / 2)) / (vi_h / float64(im_h)))

	img.Set(x1, y1, color.RGBA{0xFF, 0x00, 0x00, 0xFF})
	img.Set(x2, y2, color.RGBA{0xFF, 0x00, 0x00, 0xFF})

	draw(z1, depth + 1)
	draw(z2, depth + 1)

}

func main() {

	// Leaf
	a = 0.7 + 0.2i
	b = 0.0 + 0.0i
	c = 0.0  + 0.0i
	d = 0.67 + 0.0i

	// Koch Curve
	// a = 0.0 + 0.0i
	// b = 0.5 + 0.25i
	// c = 0.0 + 0.0i
	// d = 0.5 - 0.25i

	// C Curve
	// a =  0.0 + 0.0i
	// b = -0.5 - 0.5i
	// c =  0.0 + 0.0i
	// d = -0.5 + 0.5i

	// Triangle
	// a =  0.0 + 0.0i
	// b =  0.5 + 0.5i
	// c =  0.0 + 0.0i
	// d =  0.5 - 0.5i

	z := complex(1, 0)

	for y := 0; y < im_h; y++ {
		for x := 0; x < im_w; x++ {
			img.Set(x, y, color.RGBA{0x00, 0x00, 0x00, 0xFF})
		}
	}

	draw(z, 0);

	f, _ := os.Create("out.png")
	defer f.Close()
	png.Encode(f, img)

}