Copyright 2000 Hugh Allen     Hugh.Allen@oz.quest.com
http://homepages.borland.com/ccalvert/Contest/MarchContest/Fractal/
http://homepages.borland.com/ccalvert/Contest/MarchContest/Fractal/Mandel / Julia Explorer


// is point in main cardioid?
        // calculate stable fixed point
        tx1 := 1 - 4 * FCx;
        ty1 := 0 - 4 * FCy;
        CplxSqrt(tx1, ty1, tx1, ty1);
        //tx2 := 0.5 + 0.5 * tx1;  this one not used because
        //ty2 := 0.0 + 0.5 * ty1;  it's not a stable fixed-point
        //tx1 := 0.5 - 0.5 * tx1;
        //ty1 := 0.0 - 0.5 * ty1;
        tx1 := 1.0 - tx1;  // doubling it
        //ty1 :=     - ty1; // not needed; it'll be squared
        d := (tx1 * tx1 + ty1 * ty1); // square of magnitude of derivative at fixed-point
        if d < 1.0 then
        begin
          j := 255;
          goto done;
        end;

        // is point in circle to left of main cardioid?
        dx := FCx + 1.0;
        d := dx * dx + FCy * FCy;
        if d < 0.0625 then
        begin
          j := 255;
          goto done;
        end;
=======================================================================
Re: Mandelbrot set interior is easier to render?
Nadawca:
caos.snow@lycos.com
Data:
Tue, 19 Jun 2007 02:15:32 -0700
Grupy dyskusyjne:
sci.fractals
// check for period 1  
// I noticed you use a square root for the main
// cardiod, but you can just use :

256*(x2+y2)2 - 96*(x2+y2) + 32x - 3<= 0