Schraf Brot Fractal

[Jack]

with zoom-in/zoom-out

Code: (Select All)

_Title "Schraf Brot Animated (per Aurel 2025-06-06)"

w = 1280

h = 720

Screen _NewImage(w, h, 32): _ScreenMove 0, 0

Cls



Dim zoom As Double, dmin As Double, frame As Integer



Do

    Cls

    frame = frame + 1

    zoom = 3 / w * (1 + 0.5 * Sin(frame * 0.05)) ' zoom oscillates over time

    dmin = 0.06 * (1 + 0.3 * Cos(frame * 0.07)) ' dmin varies to make fractal edges flicker



    For a = 0 To w - 1

        For b = 0 To 1.5 * h

            x = (a - w) * zoom

            y = (b - h) * zoom

            i = 0

            d = 100

            Do

                u = x * x

                v = y * y

                If u + v > 4.8 Or i > 30 Or d < dmin Then Exit Do

                t = u - v

                y = 2 * x * y + 0.156

                x = t - 0.8

                i = i + 1

                n = Abs(u + v - 1)

                If n < d Then d = n

            Loop



            If d < dmin Then

                coul = 255 - Int(4000 * d)

                If coul < 0 Then coul = 0

                If coul > 255 Then coul = 255



                red = coul

                green = (i * 8) Mod 256

                blue = 255 - coul



                x1 = a - w / 2

                y1 = b - h / 2

                x2 = w + w / 2 - 1 - a

                y2 = h + h / 2 - b

                Line (x1, y1)-(x1 + 1, y1 + 1), _RGB(red, green, blue)

                Line (x2, y2)-(x2 + 1, y2 + 1), _RGB(red, green, blue)

            End If

        Next b

    Next a

    _Display

    _Limit 20 ' frame rate control

Loop Until _KeyDown(27) ' ESC to exit



End