以前写过的几段分型算法的代码，用来测试2d图形性能还不错

#include <fractal.h>
#include <gfx.h>

#include <math.h>
#include <debug.h>

#define PI      3.141592654

void Koch(unsigned int h, int ax, int ay, int bx, int by, int c)
{
        int cx, cy, dx, dy, ex, ey;
        double l, alpha;

        if(((bx-ax)*(bx-ax)+(by-ay)*(by-ay))<c)
        {
                gfx_lineto(h,ax, ay, bx, by);
        }
        else
        {
                cx      =       ax + (bx - ax) / 3;
                cy      =       ay + (by - ay) / 3;

                ex      =       bx - (bx - ax) / 3;
                ey      =       by-(by-ay)/3;

                l       =       sqrt(((double)ex-cx)*(ex-cx)+(ey-cy)*(ey-cy));

                alpha   =       atan(((double)ey-cy)/(ex-cx));

                if((ex - cx) < 0)
                {
                        alpha   +=      PI;
                }

                dy      =       cy + sin(alpha + PI / 3) * l;
                dx      =       cx + cos(alpha + PI / 3) * l;

                Koch(h, ax, ay, cx, cy, c);
                Koch(h, ex, ey, bx, by, c);
                Koch(h, cx, cy, dx, dy, c);
                Koch(h, dx, dy, ex, ey, c);
        }
}

void Sierpinski(unsigned int h, int x, int y, int L, int n)
{
        int x1, y1, x2, y2, x3, y3, x01, y01, x02, y02, x03, y03;

        if(n == 1)
        {
                x1=x-L/2;
                y1=y+L*(tan(PI/6))/2;
                x2=x+L/2;
                y2=y+L*(tan(PI/6))/2;
                x3=x;
                y3=y-L*(tan(PI/6));
                gfx_lineto(h, x1, y1, x2, y2);
                gfx_lineto(h, x2, y2, x3, y3);
                gfx_lineto(h, x3, y3, x1, y1);
        }
        else
        {
                x01=x-L/4;
                y01=y+L*(tan(PI/6))/4;
                x02=x+L/4;
                y02=y+L*(tan(PI/6))/4;
                x03=x;
                y03=y- L*(tan(PI/6))/2;
                Sierpinski(h, x01,y01,L/2,n-1);
                Sierpinski(h, x02,y02,L/2,n-1);
                Sierpinski(h, x03,y03,L/2,n-1);
        }
}

void Ramus(unsigned int h, int x, int y, float alpha, int L, int n)
{
        int x1, y1;
        float alpha_L, alpha_R;

        if(n > 0)
        {
                x1=x+cos(alpha)*L;
        y1=y-sin(alpha)*L;
        gfx_lineto(h, x, y, x1, y1);
        alpha_L=alpha+PI/8;
        alpha_R=alpha-PI/8;
        L=2*L/3;
        Ramus(h, x1,y1,alpha_L,L,n-1);
        Ramus(h, x1,y1,alpha_R,L,n-1);
        }
}

#define B       (PI/6)
#define s1      2
#define s2      3
#define s3      1.4
void tree(unsigned int h, int x, int y, int L, float A, float C)
{
        int x1, y1, x2, y2, x1L, y1L, x2L, y2L, x1R, y1R, x2R, y2R;

        if(L>s1)
        {
                x2      =       x + cos(A) * L;
                y2      =       y - sin(A) * L;
                x2L     =       x2 + cos(A+B) * L / s2;
                y2L     =       y2 - sin(A+B) * L / s2;
                x2R     =       x2 + cos(A-B) * L / s2;
                y2R     =       y2 - sin(A-B) * L / s2;
                x1      =       x + cos(A) * L / s2;
                y1      =       y - sin(A) * L / s2;
                x1L     =       x1 + cos(A+B) * L / s2;
                y1L     =       y1 - sin(A+B) * L / s2;
                x1R     =       x1 + cos(A-B) * L / s2;
                y1R     =       y1 - sin(A-B) * L / s2;

                /*!~30%*/
                gfx_lineto(h, x, y, x2, y2);
                gfx_lineto(h, x2, y2, x2L, y2L);
                gfx_lineto(h, x2, y2, x2R, y2R);
                gfx_lineto(h, x1, y1, x1R, y1R);
                gfx_lineto(h, x1, y1, x1L, y1L);

                tree(h, x2, y2, L/s3, A-C, C);
                tree(h, x2L, y2L, L/s2, A+B, C);
                tree(h, x2R, y2R, L/s2, A-B, C);
                tree(h, x1R, y1R, L/s2, A-B, C);
                tree(h, x1L, y1L, L/s2, A+B, C);
        }
}