#include "TrueBASIC.h"

void draw(double x1, double y1, double x2, double y2, int n);

#ifdef _MSC_VER
void __stdcall DRAW(double *x1, double *y1, double *x2, double *y2, int *n)
#else
void draw_(double *x1, double *y1, double *x2, double *y2, int *n)
#endif
{
    draw(*x1, *y1, *x2, *y2, *n);
}

void draw(double x1, double y1, double x2, double y2, int n)
{
    double dx, dy, x1n, x2n, xmid, y1n, y2n, ymid;

    if(n > 0)
    {
        dx = (x2 - x1)/3;
        dy = (y2 - y1)/3;
        x1n = x1 + dx;
        y1n = y1 + dy;
        x2n = x1 + 2*dx;
        y2n = y1 + 2*dy;
        xmid = 0.5*dx - 0.866*dy + x1n;
        ymid = 0.5*dy + 0.866*dx + y1n;
        draw(x1, y1, x1n, y1n, n-1);
        draw(x1n, y1n, xmid, ymid, n-1);
        draw(xmid, ymid, x2n, y2n, n-1);
        draw(x2n, y2n, x2, y2, n-1);
    }
    else
        GWline((float)(x1), (float)(y1), (float)(x2), (float)(y2));
}